Fermentation

20 pages, 2733 KiB

Open AccessEditor’s ChoiceArticle

A Semi-Continuous Fermentation Process for Pulque Production Using Microfiltration-Sterilized Aguamiel and Aseptic Conditions to Standardize the Overall Quality of the Beverage

by Concepción Calderón-García, Paula Cecilia Guadarrama-Mendoza, Edith Ponce-Alquicira, Adelfo Escalante, Yesica Ruiz-Ramírez and Rogelio Valadez-Blanco

Fermentation 2024, 10(7), 342; https://doi.org/10.3390/fermentation10070342 - 28 Jun 2024

Viewed by 1227

Abstract

Despite the current appreciation of pulque as a probiotic fermented beverage, pulque has been also regarded as a poor-quality product, particularly due to the lack of sanitary control during its elaboration. To address this problem, a semi-continuous fermentation system was established, emulating the [...] Read more.

Despite the current appreciation of pulque as a probiotic fermented beverage, pulque has been also regarded as a poor-quality product, particularly due to the lack of sanitary control during its elaboration. To address this problem, a semi-continuous fermentation system was established, emulating the artisanal production process. Microfiltration-sterilized aguamiel was employed as the substrate, whereas a good-quality pulque was used as the fermentation inoculum. During the fermentation, the physicochemical, microbiological (lactic acid and Leuconostoc-type bacteria and yeasts) and sensory characteristics of the must were monitored. The isolated microorganisms were identified by molecular biology and MALDI-MS techniques. The sterilization of aguamiel by microfiltration did not negatively affect its physicochemical attributes. After 6–8 days of operation of the semi-continuous bioreactor, the fermentation reached a quasi-stationary state considering most of the parameters monitored during the experiment. The final fermentation product presented similar physicochemical, microbial and sensory properties to those of the pulque inoculum. The genera identified were Leuconostoc, Lentilactobacillus, Lactobacillus, Liquorilactobacillus, Fructilactobacillus and Saccharomyces. The strains Lentilactobacillus diolivorans and Liquorilactobacillus capillatus and uvarum have not been previously isolated from pulque. In conclusion, the fermentation system developed in this work was effective to standardize the quality of pulque while preserving the positive attributes of the artisanal process, thus harnessing the probiotic properties of pulque. Full article

(This article belongs to the Section Fermentation for Food and Beverages)

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10 pages, 668 KiB

Open AccessEditor’s ChoiceArticle

Evaluation of Essential Oils and Their Blends on the Fermentative Profile, Microbial Count, and Aerobic Stability of Sorghum Silage

by Elon S. Aniceto, Tadeu S. Oliveira, José R. Meirelles, Jr., Ismael N. Silva, Elvanio J. L. Mozelli Filho, Raphael S. Gomes, Juliana P. Arévalo and Patrícia R. Moraes

Fermentation 2024, 10(7), 335; https://doi.org/10.3390/fermentation10070335 - 27 Jun 2024

Cited by 2 | Viewed by 1040

Abstract

This study aims to evaluate the effect of these essential oils and their blends on the fermentative profile, losses by gases and effluents, nutritional value, microbial count, and aerobic stability of sorghum silage. A completely randomized design was used with eight treatments and [...] Read more.

This study aims to evaluate the effect of these essential oils and their blends on the fermentative profile, losses by gases and effluents, nutritional value, microbial count, and aerobic stability of sorghum silage. A completely randomized design was used with eight treatments and four repetitions. The evaluated treatments were the following: control (CON), without any essential oil; rosemary (Ros); tea tree (TT); citronella (Cit); Ros + TT (50% + 50%); Ros + Cit (50% + 50%); TT + Cit (50% + 50%); and Ros + TT + Cit (33% + 33% + 33%). A 1000 mg/kg dose of ensiled mass (as-fed basis) was used for each of the treatments. The addition of essential oils and their blends had a significant impact (p < 0.05) on the chemical composition of sorghum silage. Crude protein content increased (p < 0.001) with the use of essential oils and their blends. The Ros affected (p < 0.05) the fibrous fraction of sorghum silage. Neutral detergent fiber in vitro degradability was reduced (p = 0.003) when we used the blend TT + Cit compared to Ros and TT. We observed that only Ros did not reduce acetic acid concentration (p = 0.031) compared to the CON. The essential oils and their blends did not affect losses (p > 0.05). Lactic acid bacteria population increased (p = 0.039) when using the blend Ros + TT + Cit compared to the CON. However, the populations of entero-bacteria and fungi were not affected (p > 0.05) by the essential oils or their blends. For aerobic stability, we observed that Ros increased (p < 0.001) the air exposure time of the sorghum silage. Furthermore, the essential oils impacted the sorghum silage’s pH, which affected (p = 0.003) its aerobic stability. In conclusion, the essential oils did not reduce sorghum silage losses. However, the Ros improved the nutritional quality and aerobic stability of sorghum silage, while the blend Ros + TT + Cit increased the lactic acid bacteria count in the silage. More in-depth studies are needed to elucidate the action of essential oils as silage additives. Full article

(This article belongs to the Special Issue Application of Fermentation Technology in Animal Nutrition)

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19 pages, 3912 KiB

Open AccessEditor’s ChoiceArticle

The Formulation of a Natural Detergent with a Biosurfactant Cultivated in a Low-Cost Medium for Use in Coastal Environmental Remediation

by Ivison A. da Silva, Fabíola Carolina G. de Almeida, Romulo N. Alves, Maristela C. C. Cunha, Jéssica Cristina M. de Oliveira, Mucio Luiz B. Fernandes and Leonie A. Sarubbo

Fermentation 2024, 10(7), 332; https://doi.org/10.3390/fermentation10070332 - 26 Jun 2024

Cited by 1 | Viewed by 1688

Abstract

Green surfactants have significant potential for improving environmental remediation methods. The aim of the present study was to formulate a green natural detergent containing the biosurfactant produced by Starmerella bombicola ATCC 22214 grown in 1.2% canola oil, 10% sucrose, and 0.5% corn steep [...] Read more.

Green surfactants have significant potential for improving environmental remediation methods. The aim of the present study was to formulate a green natural detergent containing the biosurfactant produced by Starmerella bombicola ATCC 22214 grown in 1.2% canola oil, 10% sucrose, and 0.5% corn steep liquor. The biosurfactant reduced surface tension to 31.84 mN/m and was produced at a yield of 22 g/L. Twelve formulations were proposed using cottonseed oil as the natural solvent and different stabilisers (vegetable wax, hydroxyethyl cellulose, and sodium alginate). The detergent was evaluated for its emulsifying capacity and stability over a 10-day period. Ecotoxicity was investigated using the marine recruitment test on metal plates covered with paint into which the biosurfactant was incorporated as well as tests with a microcrustacean and vegetable seeds. The formulation designated H, consisting of 1% biosurfactant, 40% cottonseed oil, and 2% hydroxyethyl cellulose, achieved the best results. The formulation exhibited both stability and emulsifying capacity (100% of petroleum). The ecotoxicity tests revealed the safety of the natural detergent. The detergent achieved satisfactory oil dispersion and solubilised 98% of the oil impregnated on the rock. The results indicate that the natural detergent holds promise for efficiently cleaning up environmental areas contaminated with oil and petroleum products. Full article

(This article belongs to the Special Issue Use of Agro-Industrial Waste and By-Products for the Sustainable Production of Eco-Friendly Surface-Active Compounds)

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12 pages, 1628 KiB

Open AccessEditor’s ChoiceArticle

Antioxidant and Anticancer Potential of Extracellular Polysaccharide from Porphyridium aerugineum (Rhodophyta)

by Juliana G. Ivanova, Tanya S. Toshkova-Yotova, Reneta A. Toshkova, Veronika R. Deleva, Ani K. Georgieva and Liliana G. Gigova

Fermentation 2024, 10(5), 259; https://doi.org/10.3390/fermentation10050259 - 15 May 2024

Cited by 3 | Viewed by 1807

Abstract

Porphyridium aerugineum is a unicellular freshwater red microalga that synthesizes and secretes into the culture medium an extracellular polysaccharide (EPS). In this study, algal growth and polysaccharide production, as well as the antioxidant capacity and antitumor effect of Porphyridium aerugineum EPS (PaEPS), were [...] Read more.

Porphyridium aerugineum is a unicellular freshwater red microalga that synthesizes and secretes into the culture medium an extracellular polysaccharide (EPS). In this study, algal growth and polysaccharide production, as well as the antioxidant capacity and antitumor effect of Porphyridium aerugineum EPS (PaEPS), were investigated. Cultivation of the microalgae was carried out in a photobioreactor under controlled conditions. Algal growth and the amount of EPS were monitored daily. The accumulated polysaccharide was extracted and lyophilized. At the end of cultivation, the concentration of microalgal biomass and PaEPS reached 3.3 and 1.2 g L⁻¹, respectively. To examine the antioxidant capacity of PaEPS, FRAP and ABTS assays were performed. The cytotoxic activity of PaEPS was evaluated on the tumor cell lines MCF-7 (breast cancer) and HeLa (cervical adenocarcinoma) and on BJ (a non-tumor human skin fibroblast cell line), using MTT assay. The results obtained indicated that P. aerugineum polysaccharide exhibited a high ABTS radical-scavenging activity reaching up to 55%. The cytotoxic effect was best expressed in MCF-7 cells treated for 72 h with 1000 µg/mL PaEPS, where tumor cell proliferation was inhibited by more than 70%. Importantly, the PaEPS treatments did not significantly affect the viability of BJ cells. These findings promote the biotechnological production of P. aerugineum extracellular polysaccharide and reveal its potential as an anticancer and antioxidant agent for future applications. Full article

(This article belongs to the Special Issue Cyanobacteria and Eukaryotic Microalgae)

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15 pages, 831 KiB

Open AccessEditor’s ChoiceArticle

Transcriptome Analysis of Sake Yeast in Co-Culture with kuratsuki Kocuria

by Karin Kobayashi and Hiromi Nishida

Fermentation 2024, 10(5), 249; https://doi.org/10.3390/fermentation10050249 - 10 May 2024

Cited by 1 | Viewed by 1558

Abstract

Kuratsuki bacteria enter the sake production process and affect the flavor and taste of sake. This study compared gene expression in the sake yeast Saccharomyces cerevisiae in co-culture with kuratsuki Kocuria to that in monoculture. Among the 5922 genes of S. cerevisiae, [...] Read more.

Kuratsuki bacteria enter the sake production process and affect the flavor and taste of sake. This study compared gene expression in the sake yeast Saccharomyces cerevisiae in co-culture with kuratsuki Kocuria to that in monoculture. Among the 5922 genes of S. cerevisiae, 71 genes were upregulated more than 2-fold, and 61 genes were downregulated less than 0.5-fold in co-culture with kuratsuki Kocuria. Among the stress-induced genes, fourteen were upregulated, and six were downregulated. Among the fourteen upregulated genes, six were induced in response to replication stress. Although the G1 cyclin gene CLN3 was upregulated by more than 2-fold, eight genes that were induced in response to meiosis and/or sporulation were also upregulated. Fourteen metabolism-related genes, for example, the glyceraldehyde-3-phosphate dehydrogenase genes TDH1, TDH2, and TDH3, were downregulated by less than 0.5-fold in co-culture with kuratsuki Kocuria. The gene expression patterns of S. cerevisiae co-cultured with kuratsuki Kocuria differed from those co-cultured with lactic acid bacteria. Therefore, S. cerevisiae responded differently to different bacterial species. This strongly suggests that kuratsuki bacteria affect gene expression in sake yeast, thereby affecting the flavor and taste of sake. Full article

(This article belongs to the Special Issue Applied and Fundamental Studies of Yeast in Fermented Foods and Beverages)

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24 pages, 2065 KiB

Open AccessEditor’s ChoiceArticle

Autochthonous Ingredients for Craft Beer Production

by Vanesa Postigo, Luz Mauro, Teresa Diaz, Roberto Saiz, Teresa Arroyo and Margarita García

Fermentation 2024, 10(5), 225; https://doi.org/10.3390/fermentation10050225 - 24 Apr 2024

Viewed by 1526

Abstract

Innovation in the beer market focuses on research into the different ingredients that make up this popular and sought-after beverage. Some of these innovations have focused on the use of autochthonous ingredients, which bring added value to products, reduce production costs and environmental [...] Read more.

Innovation in the beer market focuses on research into the different ingredients that make up this popular and sought-after beverage. Some of these innovations have focused on the use of autochthonous ingredients, which bring added value to products, reduce production costs and environmental impact, and provide beers with special organoleptic characteristics. This study focuses on the use of autochthonous ingredients from the Community of Madrid and the design of four recipes that are suited to these ingredients and consumer demand. In terms of the ingredients used, the micromalting of barley grown in the CM was carried out, while hops (Cascade variety for bittering hops and wild hops Rayo verde Tajuña and Torreta Tajuña for aroma) and yeast strains (Saccharomyces cerevisiae G 520 and G 354) were selected from previous studies, which were also sourced from the CM. For the barley malt, parameters such as protein content were determined, which was at the maximum limit but did not affect the final quality of the beers. The content of α- and β-acids in the hops was also determined, being higher in the Cascade variety. Different physicochemical analyses (GC, aromatic compounds, bitterness, colour, SO₂, polyphenols, and antioxidant capacity) were carried out to determine the quality of the beers obtained from the four recipes designed, as well as tastings by a panel of experts and consumers. Finally, two recipes were rated the best by a panel of experts and consumers, where the cereal, hop, and fruit flavours stood out for their aromatic profile. Full article

(This article belongs to the Special Issue Advances in Beverages, Food, Yeast and Brewing Research, 3rd Edition)

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20 pages, 3098 KiB

Open AccessEditor’s ChoiceArticle

Photoautotrophic Production of Docosahexaenoic Acid- and Eicosapentaenoic Acid-Enriched Biomass by Co-Culturing Golden-Brown and Green Microalgae

by Anna-Lena Thurn, Josef Schobel and Dirk Weuster-Botz

Fermentation 2024, 10(4), 220; https://doi.org/10.3390/fermentation10040220 - 18 Apr 2024

Cited by 1 | Viewed by 1783

Abstract

Marine microalgae offer a sustainable alternative source for the human diet’s essential omega-3-fatty acids, including docosahexaenoic acid (DHA, C22:6) and eicosapentaenoic acid (EPA, C20:5). However, none of them can produce DHA and EPA in a nutritionally balanced ratio of 1:1. As shown recently, [...] Read more.

Marine microalgae offer a sustainable alternative source for the human diet’s essential omega-3-fatty acids, including docosahexaenoic acid (DHA, C22:6) and eicosapentaenoic acid (EPA, C20:5). However, none of them can produce DHA and EPA in a nutritionally balanced ratio of 1:1. As shown recently, the phototrophic co-cultivation of the golden-brown microalgae Tisochrysis lutea (DHA producer) with the green microalgae Microchloropsis salina (EPA producer) can provide microalgae biomass with a balanced DHA-to-EPA ratio with increased productivity compared to monocultures. This study evaluates whether other golden-brown (Isochrysis galbana) and green microalgae (Nannochloropsis oceanica, Microchloropsis gaditana) can enable the phototrophic batch production of omega-3 fatty acids in a nutritionally balanced ratio in co-culture. All co-cultivations applying a physically dynamic climate simulation of a repeated sunny summer day in Australia in LED-illuminated flat-plate gas lift photobioreactors resulted in increased biomass concentrations compared to their respective monocultures, achieving balanced DHA-to-EPA ratios of almost 1:1. Using urea instead of nitrate as a nitrogen source increased the EPA content by up to 80% in all co-cultures. Light spectra measurements on the light-adverted side of the photobioreactor showed that increased biomass concentrations in co-cultures could have been related to enhanced light use due to the utilization of different wavelengths of the two microalgae strains, especially with the use of green light (500–580 nm) primarily by golden-brown microalgae (I. galbana) and orange light (600–620 nm) predominantly used by green microalgae (N. oceanica). Phototrophic co-cultivation processes thus promise higher areal biomass yields if microalgae are combined with complimentary light-harvesting features. Full article

(This article belongs to the Special Issue The Future of Fermentation Technology in the Biorefining Process: 2nd Edition)

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13 pages, 5694 KiB

Open AccessEditor’s ChoiceArticle

Biohydrogen, Volatile Fatty Acids, and Biomethane from Mezcal Vinasses—A Dark Fermentation Process Evaluation

by Sergio A. Díaz-Barajas, Iván Moreno-Andrade, Edson B. Estrada-Arriaga, Liliana García-Sánchez and Marco A. Garzón-Zúñiga

Fermentation 2024, 10(4), 217; https://doi.org/10.3390/fermentation10040217 - 16 Apr 2024

Viewed by 1680

Abstract

Mezcal is a drink made in Mexico, the production of which generates vinasses with a high content of organic matter (OM) that is not utilized. However, these residues have the potential to be drawn upon in dark fermentation (DF) processes to obtain biogas [...] Read more.

Mezcal is a drink made in Mexico, the production of which generates vinasses with a high content of organic matter (OM) that is not utilized. However, these residues have the potential to be drawn upon in dark fermentation (DF) processes to obtain biogas rich in biohydrogen, biomethane, and volatile fatty acids (VFAs) with the potential to become biofuels. In the present work, the effect of reaction time (RT) and organic load (OL) was assessed based on the efficiency of removing OM, the production of VFAs, and the generation and composition of biogas in a process of DF fed with mezcal vinasses. The results show that increasing the RT and decreasing the OL increases COD removal but decreases biohydrogen production. The maximum production of H₂ (64 ± 21 NmL H₂/L_reactor) was obtained with the lowest RT (1 d) and the highest OL (13.5 gCODm³d⁻¹), while the highest accumulation of VFAs (2007 ± 327 mg VFA/L) was obtained with an RT of 3 d. It was determined that RT and OL are key parameters in DF processes for biohydrogen and VFA production. Full article

(This article belongs to the Special Issue Fermentative Biohydrogen Production)

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16 pages, 5217 KiB

Open AccessEditor’s ChoiceArticle

Ethanol Production from a Mixture of Waste Tissue Paper and Food Waste through Saccharification and Mixed-Culture Fermentation

by Hongzhi Ma, Yueyao Wang, Pin Lv, Jun Zhou, Ming Gao, Dayi Qian, Bo Song and Qunhui Wang

Fermentation 2024, 10(4), 194; https://doi.org/10.3390/fermentation10040194 - 2 Apr 2024

Cited by 1 | Viewed by 2054

Abstract

This study focused on the co-fermentation of food waste and tissue paper to produce ethanol, which will eliminate the need for additional nitrogen sources and nutrients, thereby reducing production costs. In response to the inhibitory effect of the high concentrations of glucose present [...] Read more.

This study focused on the co-fermentation of food waste and tissue paper to produce ethanol, which will eliminate the need for additional nitrogen sources and nutrients, thereby reducing production costs. In response to the inhibitory effect of the high concentrations of glucose present in mixed-substrate hydrolysates on xylose fermentation, a co-fermentation process using Saccharomyces cerevisiae and Candida shehatae was proposed. This approach reduced the fermentation time by 24 h, increased the xylose utilization rate to 88%, and improved the ethanol yield from 41% to 46.5%. The impact of external conditions and corresponding optimization were also analyzed in this process. The optimum conditions were a 1:3 ratio of Saccharomyces cerevisiae to Candida shehatae, a pH of 5, and shaking at 150 r/min, and by employing dynamic temperature control, the ethanol production was increased to 21.98 g/L. Compared to conventional processes that only use Saccharomyces cerevisiae, this method enhanced the ethanol yield from 41% to 49%. Full article

(This article belongs to the Special Issue Anaerobic Digestion: Waste to Energy)

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17 pages, 1155 KiB

Open AccessEditor’s ChoiceArticle

Sourdough Fermentation of Oat and Barley Flour with Bran and Its Application in Flatbread Made with No-Time and Dough Retardation Methods

by Tomislava Grgić, Saša Drakula, Bojana Voučko, Nikolina Čukelj Mustač and Dubravka Novotni

Fermentation 2024, 10(3), 174; https://doi.org/10.3390/fermentation10030174 - 21 Mar 2024

Cited by 2 | Viewed by 2091

Abstract

Dough retardation is commonly used to extend dough shelf-life, but it poses a challenge for flatbreads due to their large surface. This study explored the sourdough fermentation of oats and barley, addressing challenges in the retardation of dough for flatbread. Sourdough, using flour [...] Read more.

Dough retardation is commonly used to extend dough shelf-life, but it poses a challenge for flatbreads due to their large surface. This study explored the sourdough fermentation of oats and barley, addressing challenges in the retardation of dough for flatbread. Sourdough, using flour only or flour blended with bran (3:1), was fermented with a LIVENDO LV1 starter at 30 °C for 24 h. The pH value, microbial viable cell count, total titratable acidity and organic acids concentration of the sourdough were measured. The properties of dough and flatbread, depending on the retardation time (24 h and 48 h), sourdough type (oat or barley) and sourdough level (30% or 50% dough weight), were investigated. Oat flour’s limited acidification improved with the inclusion of bran, resulting in a desirable pH, TTA, and lactic to acetic acid ratio after 15 h of fermentation, which were comparable to results achieved with barley sourdough. The sourdough addition slowed down the enzymatic browning of dough during retardation. Dough retardation at 24 h reduced the phytates content (32–38%) and crumb hardness (9–16%), depending on the sourdough type and level. In dough retardation, β-glucans were degraded by up to 9% in the case of oats and by up to 28% in the samples with barley. Overall, adding oat or barley sourdough at a 30% dough weight can be recommended to enhance flatbread’s nutritional value and prolong its shelf life. Full article

(This article belongs to the Special Issue Nutrition and Health of Fermented Foods, 3rd Edition)

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13 pages, 801 KiB

Open AccessEditor’s ChoiceArticle

Simultaneous Saccharification and Fermentation for Isobutanol Production from Banana Peel

by Hironaga Akita, Shodai Shibata, Tomoe Komoriya, Shinnosuke Kamei, Hiromichi Asamoto and Masakazu Matsumoto

Fermentation 2024, 10(3), 161; https://doi.org/10.3390/fermentation10030161 - 12 Mar 2024

Cited by 1 | Viewed by 2154

Abstract

Each year, near 40 million tons of banana peels are discarded around the world. This plant biomass could potentially be utilized for energy production. Simultaneous saccharification and fermentation (SSF) is an effective method for producing biofuels from plant biomasses. Since SSF with enzymatic [...] Read more.

Each year, near 40 million tons of banana peels are discarded around the world. This plant biomass could potentially be utilized for energy production. Simultaneous saccharification and fermentation (SSF) is an effective method for producing biofuels from plant biomasses. Since SSF with enzymatic hydrolysis and fermentation are performed simultaneously in the same reactor, the production process is simpler than most existing methods. Here, we describe isobutanol production using SSF with hydrothermally treated banana peel samples and an Escherichia coli strain able to utilize glucose and xylose to produce isobutanol. To enhance the glucose and xylose concentrations, the reaction conditions for the enzymatic hydrolysis of plant biomass using two kinds of saccharification enzymes were optimized, including the enzyme unit ratio, reaction temperature and sample gram. When the optimized conditions for enzymatic hydrolysis were applied to SSF, the glucose and xylose produced from the hydrothermally treated samples were consumed, producing isobutanol. Moreover, the isobutanol concentration increased with an increasing initial culture pH, reaching 1.27 g/L at pH 6.5, which was consistent with the optimal initial culture pH for isobutanol production by this E. coli strain. Taken together, these results indicate that the established method is potentially useful for industrial isobutanol production. Full article

(This article belongs to the Special Issue Bioconversion of Biomass for Effective Production of Biofuels as Well as Biobased Chemicals and Materials)

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12 pages, 1376 KiB

Open AccessEditor’s ChoiceArticle

ADM1-Based Modeling of Biohydrogen Production through Anaerobic Co-Digestion of Agro-Industrial Wastes in a Continuous-Flow Stirred-Tank Reactor System

by Christina N. Economou, Georgios Manthos, Dimitris Zagklis and Michael Kornaros

Fermentation 2024, 10(3), 138; https://doi.org/10.3390/fermentation10030138 - 29 Feb 2024

Cited by 1 | Viewed by 1777

Abstract

Biological treatment is a promising alternative for waste management considering the environmentally sustainable concept that the European Union demands. In this direction, anaerobic digestion comprises a viable waste treatment process, producing high energy-carrier gases such as biomethane and biohydrogen under certain operating conditions. [...] Read more.

Biological treatment is a promising alternative for waste management considering the environmentally sustainable concept that the European Union demands. In this direction, anaerobic digestion comprises a viable waste treatment process, producing high energy-carrier gases such as biomethane and biohydrogen under certain operating conditions. The mathematical modeling of this bioprocess can be used as a valuable tool for process scale-up with cost-effective implications. The scope of this work was the evaluation of the well-established Anaerobic Digestion Model 1 (ADM1) for use in two-stage anaerobic digestion of agro-industrial waste. Certain equations for the description of the metabolic pathways for lactate and bioethanol accumulation were implemented in the existing mechanistic model in order to enhance the model’s accuracy. The model presents a high estimation ability regarding the final product (H₂ and biogas) reaching the same maximum value for the theoretical as the experimental data of these products (0.0012 and 0.0036 m³/d, respectively). The adapted ADM1 emerges as a useful instrument for designing anaerobic co-digestion processes with the goal of achieving high yields in fermentative hydrogen production, considering mixed biomass growth mechanisms. Full article

(This article belongs to the Special Issue Biological Conversion of Biomass Residues and Waste Streams for the Sustainable Production of Biofuels and Bio-Based Products: 2nd Edition)

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17 pages, 2920 KiB

Open AccessEditor’s ChoiceArticle

Biogas Upgrading by Wild Alkaliphilic Microalgae and the Application Potential of Their Biomass in the Carbon Capture and Utilization Technology

by Yuri Kikuchi, Daichi Kanai, Kenjiro Sugiyama and Katsuhiko Fujii

Fermentation 2024, 10(3), 134; https://doi.org/10.3390/fermentation10030134 - 28 Feb 2024

Cited by 1 | Viewed by 1914

Abstract

Although biogas is a renewable energy source alternative to natural gas, it contains approximately 40 vol% CO₂ and, hence, a low calorific value. The sequestration of CO₂ from biogas is, therefore, essential before its widespread use. As CO₂ can be [...] Read more.

Although biogas is a renewable energy source alternative to natural gas, it contains approximately 40 vol% CO₂ and, hence, a low calorific value. The sequestration of CO₂ from biogas is, therefore, essential before its widespread use. As CO₂ can be easily solubilized as carbonate and bicarbonate in alkaline water, in this study, we isolated and characterized alkaliphilic wild microalgae that grow under high-level CO₂ conditions and evaluated their application potential in CO₂-removal from biogas. For this purpose, freshwater samples were enriched with 10 vol% CO₂ and an alkaline culture medium (pH 9.0), wherein almost free CO₂ was converted to carbonate and bicarbonate to yield alkaliphilic and high-level CO₂-tolerant microalgae. Ten microalgal strains of Micractinium, Chlorella, Scenedesmus/Tetradesmus, or Desmodesmus spp. were isolated, some of which demonstrated good growth even under conditions of >pH 10 and >30 vol% CO₂. All algal strains grew well through fixing biogas-derived CO₂ in a vial-scale biogas upgrading experiment, which reduced the CO₂ level in biogas to an undetectable level. These strains yielded antioxidant carotenoids, including lutein, astaxanthin, zeaxanthin, and β-carotene, particularly rich in lutein (up to 7.3 mg/g dry cells). In addition, these strains contained essential amino acids, accounting for 42.9 mol% of the total amino acids on average, and they were rich in unsaturated fatty acids (comprising 62.2 wt% of total fatty acids). The present study identified strains that can contribute to biogas upgrading technology, and the present findings suggest that their biomass can serve as useful raw material across the food, nutraceutical, and feed industries. Full article

(This article belongs to the Special Issue Microbial Culture and Isolation for the Production of Biofuels)

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12 pages, 2159 KiB

Open AccessEditor’s ChoiceArticle

Differences in the Volatile Profile of Apple Cider Fermented with Schizosaccharomyces pombe and Schizosaccharomyces japonicus

by Nicola Ferremi Leali, Elisa Salvetti, Giovanni Luzzini, Andrea Salini, Davide Slaghenaufi, Salvatore Fusco, Maurizio Ugliano, Sandra Torriani and Renato L. Binati

Fermentation 2024, 10(3), 128; https://doi.org/10.3390/fermentation10030128 - 25 Feb 2024

Cited by 2 | Viewed by 1721

Abstract

In this study, two strains of Schizosaccharomyces pombe (NCAIM Y01474^T and SBPS) and two strains of Schizosaccharomyces japonicus (DBVPG 6274^T, M23B) were investigated for their capacity to ferment apple juice and influence the volatile compounds of cider compared to Saccharomyces [...] Read more.

In this study, two strains of Schizosaccharomyces pombe (NCAIM Y01474^T and SBPS) and two strains of Schizosaccharomyces japonicus (DBVPG 6274^T, M23B) were investigated for their capacity to ferment apple juice and influence the volatile compounds of cider compared to Saccharomyces cerevisiae EC1118. The ethanol tolerance and deacidification capacity of Schizosaccharomyces yeasts could make them potential substitutes for the commonly used S. cerevisiae starter cultures. Despite different time courses (10–30 d), all strains could complete the fermentation process, and Schizosaccharomyces strains reduced the concentration of malic acid in the apple juice. Results indicated that each yeast exerted a distinctive impact on the volatile profile of the apple cider, giving final products separated using a principal component analysis. The volatile composition of the cider exhibited significant differences in the concentration of alcohols, esters, and fatty acids. Particularly, the flocculant strain S. japonicus M23B increased the levels of ethyl acetate (315.44 ± 73.07 mg/L), isoamyl acetate (5.99 ± 0.13 mg/L), and isoamyl alcohol (24.77 ± 15.19 mg/L), while DBVPG 6274^T incremented the levels of phenyl ethyl alcohol and methionol up to 6.19 ± 0.51 mg/L and 3.72 ± 0.71 mg/L, respectively. A large production of terpenes and ethyl esters (e.g., ethyl octanoate) was detected in the cider fermented by S. cerevisiae EC1118. This study demonstrates, for the first time, the possible application of S. japonicus in cider-making to provide products with distinctive aromatic notes”. Full article

(This article belongs to the Special Issue Advances in Beverages, Food, Yeast and Brewing Research, 3rd Edition)

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13 pages, 278 KiB

Open AccessEditor’s ChoiceArticle

Synergistic Effects of Essential Oil Blends and Fumaric Acid on Ruminal Fermentation, Volatile Fatty Acid Production and Greenhouse Gas Emissions Using the Rumen Simulation Technique (RUSITEC)

by Joel O. Alabi, Peter A. Dele, Deborah O. Okedoyin, Michael Wuaku, Chika C. Anotaenwere, Oludotun O. Adelusi, DeAndrea Gray, Kelechi A. Ike, Olatunde A. Oderinwale, Kiran Subedi and Uchenna Y. Anele

Fermentation 2024, 10(2), 114; https://doi.org/10.3390/fermentation10020114 - 19 Feb 2024

Cited by 4 | Viewed by 2028

Abstract

This study investigated the combined impact of essential oil blends (EOBs) and fumaric acid (FA) on ruminal fermentation in dairy cows using the rumen simulation technique (RUSITEC) system. Three rumen-cannulated, non-lactating Holstein Friesian cows served as inoculum donors. The substrate, a total mixed [...] Read more.

This study investigated the combined impact of essential oil blends (EOBs) and fumaric acid (FA) on ruminal fermentation in dairy cows using the rumen simulation technique (RUSITEC) system. Three rumen-cannulated, non-lactating Holstein Friesian cows served as inoculum donors. The substrate, a total mixed ration (TMR), comprised corn silage, alfalfa hay, and a concentrate mix in a 3:1:1 ratio. The four treatments evaluated were Control (TMR without additives), EFA1 (TMR + EOB1 + FA), EFA2 (TMR + EOB2 + FA), and EFA3 (TMR + EOB3 + FA). Sixteen fermentation chambers were randomly assigned to the treatments, each with four replicates, following a completely randomized design during a 9-day experimental period. EOBs and FA were added at 10 µL/g feed and 3% of TMR, respectively. After a 4-day adaptation, samples were collected for 5 days. Results revealed that EFA1 significantly reduced (p = 0.0351) CH₄ emissions by 60.2% without negatively impacting dry matter disappearance, fiber fraction digestibility, pH, or gas volume. All EFAs increased (p < 0.001) the propionate molar proportion and decreased (p < 0.001) the acetate-to-propionate ratio. EFA2 decreased (p < 0.05) the acetate proportion by 3.3% compared to the control. In conclusion, EFA1 is recommended as an effective nutritional intervention to mitigate CH₄ emissions and optimize ruminal fermentation in dairy cows. Full article

(This article belongs to the Special Issue In Vitro Digestibility and Ruminal Fermentation Profile, 2nd Edition)

14 pages, 1449 KiB

Open AccessEditor’s ChoiceArticle

The Potential Use of Pseudomonas stutzeri as a Biocatalyst for the Removal of Heavy Metals and the Generation of Bioelectricity

by Rojas-Flores Segundo, Magaly De La Cruz-Noriega, Luis Cabanillas-Chirinos, Nélida Milly Otiniano, Nancy Soto-Deza, Walter Rojas-Villacorta and Mayra De La Cruz-Cerquin

Fermentation 2024, 10(2), 113; https://doi.org/10.3390/fermentation10020113 - 19 Feb 2024

Cited by 1 | Viewed by 2121

Abstract

Currently, industry in all its forms is vital for the human population because it provides the services and goods necessary to live. However, this process also pollutes soils and rivers. This research provides an environmentally friendly solution for the generation of electrical energy [...] Read more.

Currently, industry in all its forms is vital for the human population because it provides the services and goods necessary to live. However, this process also pollutes soils and rivers. This research provides an environmentally friendly solution for the generation of electrical energy and the bioremediation of heavy metals such as arsenic, iron, and copper present in river waters used to irrigate farmers’ crops. This research used single-chamber microbial fuel cells with activated carbon and zinc electrodes as anodes and cathodes, respectively, and farmers’ irrigation water contaminated with mining waste as substrate. Pseudomonas stutzeri was used as a biocatalyst due to its ability to proliferate at temperatures between 4 and 44 °C—at which the waters that feed irrigated rivers pass on their way to the sea—managing to generate peaks of electric current and voltage of 4.35 mA and 0.91 V on the sixth day, which operated with an electrical conductivity of 222 mS/cm and a pH of 6.74. Likewise, the parameters of nitrogen, total organic carbon, carbon lost on the ignition, dissolved organic carbon, and chemical oxygen demand were reduced by 51.19%, 79.92%, 64.95%, 79.89%, 79.93%, and 86.46%. At the same time, iron, copper, and arsenic values decreased by 84.625, 14.533, and 90.831%, respectively. The internal resistance values shown were 26.355 ± 4.528 Ω with a power density of 422.054 mW/cm² with a current density of 5.766 A/cm². This research gives society, governments, and private companies an economical and easily scalable prototype capable of simultaneously generating electrical energy and removing heavy metals. Full article

(This article belongs to the Special Issue Recent Advances in Bioconversion of Biomass to Value-Added Products)

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17 pages, 2284 KiB

Open AccessEditor’s ChoiceArticle

Dynamic Optimization of Lactic Acid Production from Grape Stalk Solid-State Fermentation with Rhizopus oryzae Applying a Variable Temperature Profile

by María Carla Groff, Sandra Edith Noriega, Rocío Mariel Gil, Nadia Pantano and Gustavo Scaglia

Fermentation 2024, 10(2), 101; https://doi.org/10.3390/fermentation10020101 - 8 Feb 2024

Cited by 3 | Viewed by 2058

Abstract

Lactic acid is widely used in the food industry. It can be produced via chemical synthesis or biotechnological pathways by using renewable resources as substrates. The main challenge of sustainable production lies in reaching productivities and yields that allow for their industrial production. [...] Read more.

Lactic acid is widely used in the food industry. It can be produced via chemical synthesis or biotechnological pathways by using renewable resources as substrates. The main challenge of sustainable production lies in reaching productivities and yields that allow for their industrial production. In this case, the application of process engineering becomes a crucial tool to improve the performance of bioprocesses. In this work, we performed the solid-state fermentation of grape stalk using Rhizopus oryzae NCIM 1299 to obtain lactic acid, employing three different temperatures (22, 35, and 40 °C) and a relative humidity of 50%. The Logistic and First-Order Plus Dead Time models were adjusted for fungal biomass growth, and the Luedeking and Piret with Delay Time model was used for lactic acid production, obtaining higher R² values in all cases. At 40 °C, it was observed that Rhizopus oryzae grew in pellet form, resulting in an increase in lactic acid productivity. In this context, the effect of temperature on the kinetic parameters was evaluated with a polynomial correlation. Finally, using this correlation, a smooth and continuous optimal temperature profile was obtained by a dynamic optimization method, improving the final lactic acid concentration by 53%. Full article

(This article belongs to the Special Issue Fermented Foods: Traditional Processes, Innovative Strategies, and Challenges 2.0)

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18 pages, 8547 KiB

Open AccessEditor’s ChoiceArticle

Mixotrophic Syngas Conversion Enables the Production of meso-2,3-butanediol with Clostridium autoethanogenum

by Anne Oppelt, Anton Rückel, Markus Rupp and Dirk Weuster-Botz

Fermentation 2024, 10(2), 102; https://doi.org/10.3390/fermentation10020102 - 8 Feb 2024

Cited by 1 | Viewed by 2591

Abstract

Providing simultaneously autotrophic and heterotrophic carbon sources is a promising strategy to overcome the limits of autotrophic syngas fermentations. D-xylose and L-arabinose are particularly interesting as they can be obtained by the hydrolysis of lignocellulosic biomass. The individual conversion of varying initial concentrations [...] Read more.

Providing simultaneously autotrophic and heterotrophic carbon sources is a promising strategy to overcome the limits of autotrophic syngas fermentations. D-xylose and L-arabinose are particularly interesting as they can be obtained by the hydrolysis of lignocellulosic biomass. The individual conversion of varying initial concentrations of these pentoses and D-fructose as reference was studied with C. autoethanogenum in fully controlled stirred-tank reactors with a continuous syngas supply. All mixotrophic batch processes showed increased biomass and product formation compared to an autotrophic reference process. Simultaneous CO and D-xylose or L-arabinose conversion was observed in contrast to D-fructose. In the mixotrophic batch processes with L-arabinose or D-xylose, the simultaneous CO and sugar conversion resulted in high final alcohol-to-acid ratios of up to 58 g g⁻¹. L-arabinose was superior as a mixotrophic carbon source because biomass and alcohol concentrations (ethanol and 2,3-butanediol) were highest, and significant amounts of meso-2,3-butanediol (>1 g L⁻¹) in addition to D-2,3-butanediol (>2 g L⁻¹) were solely produced with L-arabinose. Furthermore, C. autoethanogenum could not produce meso-2,3 butanediol under purely heterotrophic conditions. The mixotrophic production of meso-2,3-butanediol from L-arabinose and syngas, both available from residual lignocellulosic biomass, is very promising for use as a monomer for bio-based polyurethanes or as an antiseptic agent. Full article

(This article belongs to the Special Issue Microbial Fixation of CO₂ to Fuels and Chemicals)

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25 pages, 3178 KiB

Open AccessEditor’s ChoiceArticle

Innovative Bicultured Lactic–Acetic Acid Co-fermentation Improves Jujube Puree’s Functionality and Volatile Compounds

by Turkson Antwi Boasiako, Yuqing Xiong, Isaac Duah Boateng, Jeffrey Appiagyei, Yanshu Li, Kerry Clark, Afusat Yinka Aregbe, Sanabil Yaqoob and Yongkun Ma

Fermentation 2024, 10(1), 71; https://doi.org/10.3390/fermentation10010071 - 21 Jan 2024

Cited by 4 | Viewed by 2471

Abstract

Jujubes (Ziziphus jujuba Mill), characterized by a rich profile of bioactive compounds, have been historically less exploited due to their unappealing sensory characteristics when dried, including delayed bitterness and a limited shelf life when fresh. Co-fermented jujube puree has emerged as a [...] Read more.

Jujubes (Ziziphus jujuba Mill), characterized by a rich profile of bioactive compounds, have been historically less exploited due to their unappealing sensory characteristics when dried, including delayed bitterness and a limited shelf life when fresh. Co-fermented jujube puree has emerged as a strategy for enhancing its functional food potential. This study examined the impact of 8-day bicultured Junzao jujube puree, employing both commercial and indigenous Chinese lactic and acetic acid bacteria. Our investigation encompassed an assessment of functionality (cellular profile, antioxidant properties, color, free amino acids, phenolic profiling, volatiles elucidation using headspace-solid phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC-MS), aroma analysis using electronic nose), and microstructural analysis using scanning electron microscopy (SEM). Viable counts of bicultured purees showed probiotic effects exceeding 6–7 log CFU/mL. Strong positive correlations were observed between phenolic compounds (chlorogenic acid, rutin, p-coumaric acid) and antioxidant capacities (ABTS-RSA and DPPH-RSA). The darker color of raw jujube puree was modified, exemplified by a significant (p < 0.05) negative correlation between overall color difference and cyanidin 3-O-rutinoside (R² = −0.768). Purees, particularly those containing bicultures of Lactobacillus helveticus Lh 43 and Acetobacter pasteurianus Ap-As.1.41 HuNiang 1.01 exhibited the highest potential free amino acid content (157.17 ± 1.12 mg/100 g FW) compared to the control (184.03 ± 1.16 mg/100 g FW) with a distinctive formation of L-methionine in biculture of Lactiplantibacillus plantarum Lp 28 and A. pasteurianus Ap-As.1.41 HuNiang 1.01. The phenolic profile of Lacticaseibacillus casei Lc 122 and A. pasteurianus Ap-As.1.41 HuNiang 1.01 increased by 22.79% above the control (48.34 mg/100 g FW) while biculture: L. helveticus Lh 43 and A. pasteurianus Ap-As.1.41 HuNiang 1.01 were enhanced by 4.37%, with the lowest profile in Lp. plantarum Lp 28 and A. pasteurianus Ap-As.1.41 HuNiang 1.01 (46.85 mg/100 g FW). The electronic nose revealed the predominant presence of sulfur, terpenes, and alcohol sensor bioactives in the fermented purees. HS-SPME-GC-MS analysis identified 80 volatile compounds in the bicultured purees, with esters constituting the major group (42%). Furthermore, SEM analysis unveiled massive microscopic alterations in the bicultured purees compared to the unfermented puree. These results collectively demonstrated that lactic–acetic acid co-fermentation serves to biovalorize Junzao jujube puree, enhancing its organoleptic appeal and extending its shelf life. Full article

(This article belongs to the Special Issue Bioactivity Change in Fermented Foods)

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18 pages, 729 KiB

Open AccessEditor’s ChoiceArticle

Non-Conventional Yeasts from Mozzarella Cheese Whey and Artisanal Sourdoughs: Leavening Capacity and Impact on Bread Sensory Profile

by Floriana Boscaino, Elena Ionata, Salvatore De Caro and Alida Sorrentino

Fermentation 2024, 10(1), 68; https://doi.org/10.3390/fermentation10010068 - 19 Jan 2024

Viewed by 1669

Abstract

Non-conventional yeasts (NCYs) (i.e., non-Saccharomyces) are used as alternative starters to promote aroma complexity of fermented foods (e.g., bakery products). A total of 66 yeasts isolated from artisanal food matrices (bread and pizza sourdoughs and milk whey) from different geographical areas [...] Read more.

Non-conventional yeasts (NCYs) (i.e., non-Saccharomyces) are used as alternative starters to promote aroma complexity of fermented foods (e.g., bakery products). A total of 66 yeasts isolated from artisanal food matrices (bread and pizza sourdoughs and milk whey) from different geographical areas of the Campania region (Italy) were screened for physiological and technological characteristics such as leavening ability, resistance to NaCl and pH, exopolysaccharide and phytase activity production, and carbohydrate assimilation. Selected and isolated microorganisms were also used to study the leavening kinetics in experimental doughs as mixed inocula of two different strains. Volatile organic compounds (VOCs) of the inoculated doughs were analyzed with solid-phase microextraction/gas chromatography–mass spectrometry (SPME/GC-MS). Most of the strains belonged to non-Saccharomyces species (Pichia kudriavzevii, Kluyveromyces marxianus) and Saccharomyces (S. cerevisiae). Several strains produced exopolysaccharides (EPSs), that are important for dough rheological properties. Moreover, yeasts isolated from whey showed extracellular phytase activity. The mixed starter culture of the S. cerevisiae and NCY strains showed a synergic effect that enhanced the doughs’ aroma complexity. The use of non-conventional yeasts mixed with S. cerevisiae strains can be advantageous in the bakery industry because they improve the bread aroma profiles and nutritional properties by bioactive molecule production. Full article

(This article belongs to the Special Issue New Aspect: Progress of Molds and Yeasts in Fermented-Food Production)

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20 pages, 3037 KiB

Open AccessEditor’s ChoiceArticle

Biochemical Characterization of Three Heterologous Lactic Acid Bacteria Laccases from Pediococcus, Lactobacillus, and Lactococcus Genus and Their Potential to Degrade Biogenic Amines Using ABTS and Epicatechin as Mediators

by Isaac Monroy, Isidoro Olmeda, Sergi Ferrer and Isabel Pardo

Fermentation 2024, 10(1), 32; https://doi.org/10.3390/fermentation10010032 - 30 Dec 2023

Cited by 1 | Viewed by 1839

Abstract

In this study, we cloned and characterized three bacterial laccases from strains of the species Pediococcus parvulus, Lacticaseibacillus paracasei, and Lactococcus lactis isolated from wine and cheese and evaluated their biogenic amine degradation abilities in the presence/absence of artificial 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid [...] Read more.

In this study, we cloned and characterized three bacterial laccases from strains of the species Pediococcus parvulus, Lacticaseibacillus paracasei, and Lactococcus lactis isolated from wine and cheese and evaluated their biogenic amine degradation abilities in the presence/absence of artificial 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) or natural (epicatechin) mediator compounds. Although some recombinant bacterial laccases have been characterized and found to be biological tools for degrading biogenic amines with or without the use of mediators, no prior research has investigated the role of natural mediators, like phenolic substrates found in wine and certain vegetable foods, in the degradation of biogenic amines. The three recombinant bacterial laccases exhibited sigmoidal kinetics and had similar molecular mass but varied in k_0.5, k_cat, and specific activity toward ABTS. They are acidophilic and have an optimal temperature of 28 °C. However, they exhibit low thermal stability at temperatures higher than 37 °C. The three laccases were capable of degrading dopamine without the use of mediators, while the other amines were not degraded. The presence of ABTS enhanced the degradation of dopamine and tyramine, but the addition of epicatechin did not improve their degradation. This study presents a comparison of the laccases’ biogenic amine-degrading efficiency using different mediators. This is the first time such a comparison has been made. Full article

(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)

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26 pages, 5115 KiB

Open AccessEditor’s ChoiceArticle

Dip Hopping Technique and Yeast Biotransformations in Craft Beer Productions

by Paolo Passaghe, Lara Tat, Alba Goi, Luca Vit and Stefano Buiatti

Fermentation 2024, 10(1), 30; https://doi.org/10.3390/fermentation10010030 - 29 Dec 2023

Cited by 2 | Viewed by 1851

Abstract

This paper evaluates the effects of an alternative hopping technique, called dip hopping, on beer. This technique involves infusing hops in hot water (or in a portion of wort) and subsequently combining the infusion with the wort (after wort cooling) directly in the [...] Read more.

This paper evaluates the effects of an alternative hopping technique, called dip hopping, on beer. This technique involves infusing hops in hot water (or in a portion of wort) and subsequently combining the infusion with the wort (after wort cooling) directly in the fermenter when the yeast is added for fermentation. The reference beers were produced employing the “traditional” late hopping technique, and the experimental beers were produced using the dip hopping technique. A variety of hops with a significant concentration of essential oil and a strain of yeast with high β-glucosidic activity capable of releasing aromatic molecules from precursors supplied by hops were used. The samples were analysed in terms of alcohol content, degree of attenuation, colour, and bitterness. Sensory analysis and gas chromatography analysis were also performed. The data showed statistically significant differences between the reference beers and the experimental beers, with the latter featuring greater hints of citrus, fruity, floral, and spicy aromas. As an overall effect, there was an increase in the olfactory and gustatory pleasantness of the beers produced with the dip hopping technique. Full article

(This article belongs to the Special Issue Wine and Beer Fermentation)

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15 pages, 946 KiB

Open AccessEditor’s ChoiceArticle

Biodiversity and Safety: Cohabitation Experimentation in Undefined Starter Cultures for Traditional Dairy Products

by Luigi Chessa, Elisabetta Daga, Ilaria Dupré, Antonio Paba, Maria C. Fozzi, Davide G. Dedola and Roberta Comunian

Fermentation 2024, 10(1), 29; https://doi.org/10.3390/fermentation10010029 - 29 Dec 2023

Cited by 1 | Viewed by 1871

Abstract

Natural starter cultures, characterised by undefined microbiota, can contribute to the technological process, giving peculiar characteristics to artisanal fermented foods. Several species have a long history of safe use and have obtained Qualified Presumption of Safety (QPS) status from the European Food Safety [...] Read more.

Natural starter cultures, characterised by undefined microbiota, can contribute to the technological process, giving peculiar characteristics to artisanal fermented foods. Several species have a long history of safe use and have obtained Qualified Presumption of Safety (QPS) status from the European Food Safety Authority (EFSA), whereas others (non-QPS) could represent a potential risk for consumers’ health and must undergo a safety assessment. In this work, the biodiversity, at species and strain level, by pulsed-field gel electrophoresis (PFGE) and (GTG)₅ rep-PCR, of an undefined natural starter culture, in frozen and lyophilized form, obtained from ewe’s raw milk avoiding thermal treatment or microbial selection, was investigated. The culture was constituted by different biotypes of Enterococcus durans, Enterococcus faecium, Enterococcus faecalis, and Lacticaseibacillus paracasei. Streptococcus oralis and Streptococcus salivarius were also found, over species belonging to the Streptococcus bovis–Streptococcus equinus complex (SBSEC), like Streptococcus gallolyticus subsp. macedonicus, Streptococcus lutetiensis, and Streptococcus equinus. Molecular investigation on virulence and antibiotic resistance genes, as well as minimum inhibitory concentration (MIC) determination, revealed that all the non-QPS strains can be considered safe in the perspective of using this culture for cheesemaking. The obtainment of a natural culture directly from ewe’s raw milk bypassing thermal treatment and selection of pro-technological bacteria can be advantageous in terms of biodiversity preservation, but non-QPS microorganisms can be included in the natural starter and also in cheeses, especially in traditional ones obtained from fermenting raw milk. Following EFSA guidelines, artisanal factories should not be allowed to produce starter cultures by themselves from raw milk, running the risk of including some non-QPS species in their culture, and only selected starters could be used for cheesemaking. A revision of the criteria of QPS guidelines should be necessary. Full article

(This article belongs to the Special Issue Development and Application of Starter Cultures)

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23 pages, 4827 KiB

Open AccessEditor’s ChoiceArticle

Model Identification of E. coli Cultivation Process Applying Hybrid Crow Search Algorithm

by Olympia Roeva and Dafina Zoteva

Fermentation 2024, 10(1), 12; https://doi.org/10.3390/fermentation10010012 - 22 Dec 2023

Viewed by 1559

Abstract

Cultivation process (CP) modeling and optimization are ambitious tasks due to the nonlinear nature of the models and interdependent parameters. The identification procedures for such models are challenging. Metaheuristic algorithms exhibit promising performance for such complex problems since a near-optimal solution can be [...] Read more.

Cultivation process (CP) modeling and optimization are ambitious tasks due to the nonlinear nature of the models and interdependent parameters. The identification procedures for such models are challenging. Metaheuristic algorithms exhibit promising performance for such complex problems since a near-optimal solution can be found in an acceptable time. The present research explores a new hybrid metaheuristic algorithm built upon the good exploration of the genetic algorithm (GA) and the exploitation of the crow search algorithm (CSA). The efficiency of the proposed GA-CSA hybrid is studied with the model parameter identification procedure of the E. coli BL21(DE3)pPhyt109 fed-batch cultivation process. The results are compared with those of the pure GA and pure CSA applied to the same problem. A comparison with two deterministic algorithms, i.e., sequential quadratic programming (SQP) and the Quasi-Newton (Q-N) method, is also provided. A more accurate model is obtained by the GA-CSA hybrid with fewer computational resources. Although SQP and Q-N find a solution for a smaller number of function evaluations, the resulting models are not as accurate as the models generated by the three metaheuristic algorithms. The InterCriteria analysis, a mathematical approach to revealing certain relations between given criteria, and a series of statistical tests are employed to prove that there is a statistically significant difference between the results of the three stochastic algorithms. The obtained mathematical models are then successfully verified with a different set of experimental data, in which, again, the closest one is the GA-CSA model. The GA-CSA hybrid proposed in this paper is proven to be successful in the collaborative hybridization of GA and CSA with outstanding performance. Full article

(This article belongs to the Special Issue Modeling Methods for Fermentation Processes)

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13 pages, 5608 KiB

Open AccessEditor’s ChoiceArticle

New Insights into the Biosynthesis of Succinic Acid by Actinobacillus succinogenes with the Help of Its Engineered Strains

by Chunmei Chen and Pu Zheng

Fermentation 2023, 9(12), 1026; https://doi.org/10.3390/fermentation9121026 - 15 Dec 2023

Cited by 2 | Viewed by 2209

Abstract

Succinic acid (SA), a C4 tricarboxylic acid cycle intermediate, is used as raw material for bulk chemicals and specialty chemicals, such as tetrahydrofuran and 1,4-butanediol, as well as also being used to synthesize the biodegradable biopolymers PBS (polymer poly (butylene succinate)). Actinobacillus succinogenes [...] Read more.

Succinic acid (SA), a C4 tricarboxylic acid cycle intermediate, is used as raw material for bulk chemicals and specialty chemicals, such as tetrahydrofuran and 1,4-butanediol, as well as also being used to synthesize the biodegradable biopolymers PBS (polymer poly (butylene succinate)). Actinobacillus succinogenes, which is facultative anaerobic and gram-negative, is one of the most promising natural SA-producing organisms, but genetic engineering of A. succinogenes is rare so far. In this study, a series of engineered strains was constructed using the pLGZ922 expression vector and a cytosine base editor (CBE) based on CRIPSR/Cas9; we found that phosphoenolpyruvate carboxylase (PEPC) was more important for the CO₂ fixation pathway than pyruvate carboxylase (PYC) in A. succinogenes, and the annotated oxaloacetic acid decarboxylase (Asuc_0301 and Asuc_0302) had little correlation with the SA synthesis pathway. The by-product pathway was closely related to cell growth, and overexpression of FDH was beneficial to growth, while the knockout of the ackA gene reduced the growth. For the first time, the hypothetic sugars and SA transporters were mined and identified in A. succinogenes, of which Asuc_0914 was responsible for glucose uptake, and Asuc_0715 and Asuc_0716 constituted SA exporters. This deepens the understanding of SA biosynthesis in A. succinogenes and is also valuable for SA production by fermentation. Full article

(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)

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18 pages, 2818 KiB

Open AccessEditor’s ChoiceArticle

The Application of Adaptive Model Predictive Control for Fed-Batch Escherichia coli BL21 (DE3) Cultivation and Biosynthesis of Recombinant Proteins

by Konstantins Dubencovs, Arturs Suleiko, Elina Sile, Ivars Petrovskis, Inara Akopjana, Anastasija Suleiko, Vytautas Galvanauskas, Kaspars Tars and Juris Vanags

Fermentation 2023, 9(12), 1015; https://doi.org/10.3390/fermentation9121015 - 12 Dec 2023

Cited by 1 | Viewed by 1961

Abstract

A model predictive control (MPC) method was investigated as a route to optimize and control the growth of E. coli BL21 (DE3) and biosynthesis of two different recombinant proteins (nerve growth factor NGF and coat protein of bacteriophage Qβ (Qβ-CP)). To determine the [...] Read more.

A model predictive control (MPC) method was investigated as a route to optimize and control the growth of E. coli BL21 (DE3) and biosynthesis of two different recombinant proteins (nerve growth factor NGF and coat protein of bacteriophage Qβ (Qβ-CP)). To determine the target trajectory for the E. coli cultivation process and estimate the model parameters, the off-line run-to-run optimization method was used. The proven method allowed us to successfully control the growth of microbial biomass, with a deviation of 6–12% from the target trajectory. It was proven that it is possible to obtain a “Golden Batch” profile for the implementation of MPC using datasets from only four to eight fermentation runs. The method showed its robustness when the cultivation of E. coli was carried out with two different titrant supply control systems—volumetric and gravimetric. Furthermore, the MPC method exhibited high adaptability, reliability, and resistance to various types of disturbances. MPC proved to be a reliable and effective method for controlling the cultivation and recombinant protein biosynthesis of fast-growing microorganisms such as E. coli. Full article

(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)

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13 pages, 2310 KiB

Open AccessEditor’s ChoiceArticle

Generation of a Culex Male Mosquito Sex-Separation RNAi Yeast Strain Using Cas-CLOVER and Super PiggyBac Engineering in Saccharomyces cerevisiae

by Corey Brizzee, Keshava Mysore, Teresia M. Njoroge, Seth McConnell, Jack Crawford and Molly Duman-Scheel

Fermentation 2023, 9(12), 999; https://doi.org/10.3390/fermentation9120999 - 23 Nov 2023

Viewed by 2140

Abstract

Several emerging mosquito control technologies require mass releases of adult male mosquitoes. Previous studies resulted in the generation of a laboratory female-specific larvicidal yeast strain targeting the GGT gene, which facilitated the laboratory sex separation of male Culex quinquefasciatus mosquitoes. Global deployment of [...] Read more.

Several emerging mosquito control technologies require mass releases of adult male mosquitoes. Previous studies resulted in the generation of a laboratory female-specific larvicidal yeast strain targeting the GGT gene, which facilitated the laboratory sex separation of male Culex quinquefasciatus mosquitoes. Global deployment of this yeast-based sex-separation technology requires engineering second generation yeast strains which can be used in industrial-scale fermentations to support global mosquito control programs. In this study, the RNA-guided Cas-CLOVER system was used in combination with piggyBac transposase to generate robust Saccharomyces cerevisiae strains with multiple integrated copies of the insecticidal GGT shRNA expression cassette. Top expressing Cas-CLOVER strains killed Culex quinquefasciatus female larvae which consumed the yeast, facilitating male sex separation. Scaled fermentation resulted in kilogram-scale production of the yeast, which can be heat-killed and dried for global deployment to mosquito mass-rearing facilities. Full article

(This article belongs to the Special Issue Advances in Yeast Biotechnology from Genomics to Industry)

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19 pages, 3232 KiB

Open AccessEditor’s ChoiceArticle

Purified Acidic Sophorolipid Biosurfactants in Skincare Applications: An Assessment of Cytotoxic Effects in Comparison with Synthetic Surfactants Using a 3D In Vitro Human Skin Model

by Simms A. Adu, Matthew S. Twigg, Patrick J. Naughton, Roger Marchant and Ibrahim M. Banat

Fermentation 2023, 9(11), 985; https://doi.org/10.3390/fermentation9110985 - 18 Nov 2023

Cited by 2 | Viewed by 2519

Abstract

Acidic sophorolipids (Acidic SL), congeners of sophorolipid biosurfactants, offer a potential alternative to synthetic sodium lauryl ether sulphate (SLES) in skincare applications. However, major challenges associated with the laboratory-based investigations of the cytotoxic effects of Acidic SL have been the utilisation of impure [...] Read more.

Acidic sophorolipids (Acidic SL), congeners of sophorolipid biosurfactants, offer a potential alternative to synthetic sodium lauryl ether sulphate (SLES) in skincare applications. However, major challenges associated with the laboratory-based investigations of the cytotoxic effects of Acidic SL have been the utilisation of impure and/or poorly characterised congeners as well as the use of monolayers of skin cells in in vitro assays. While the former limitation makes glycolipids less attractive for use in academic research and skincare applications, the latter does not provide an accurate representation of the in vivo human skin. The present study, therefore, for the first time, assessed the cytotoxic effects of 96% pure Acidic SL on a 3D in vitro skin model in comparison with SLES, with the aim of investigating a natural alternative to synthetic surfactants for potential use in skincare applications. The 3D in vitro skin model was colonised with Staphylococcus epidermidis for 12 h, and afterwards treated with either Acidic SL or SLES at 100 μg mL⁻¹ for a further 12 h. Subsequently, the cytotoxic effects of Acidic SL in comparison with SLES were assessed using a combination of microbiology, molecular biology techniques, immunoassays, and histological analyses. It was demonstrated that Acidic SL had no deleterious effects on the viability of S. epidermidis, tissue morphology, filaggrin expression, and the production of inflammatory cytokines in comparison to SLES. These findings, in conjunction with the possibility to produce Acidic SL from cheaper renewable natural resources, demonstrate that Acidic SL could offer a potential sustainable alternative to synthetic surfactants. Full article

(This article belongs to the Special Issue Production and Application of Bioactive Biosurfactants)

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17 pages, 10207 KiB

Open AccessEditor’s ChoiceArticle

Monitoring β-Fructofuranosidase Activity through Kluyveromyces marxianus in Bioreactor Using a Lab-Made Sequential Analysis System

by Edwin J. Barbosa-Hernández, Jorge E. Pliego-Sandoval, Anne Gschaedler-Mathis, Javier Arrizon-Gaviño, Alejandro Arana-Sánchez, Ricardo Femat and Enrique J. Herrera-López

Fermentation 2023, 9(11), 963; https://doi.org/10.3390/fermentation9110963 - 10 Nov 2023

Cited by 2 | Viewed by 2159

Abstract

The yeast Kluyveromyces marxianus has shown the potential to produce

β

-fructofuranosidases, which are enzymes capable of hydrolyzing

β

-fructofuranosides links of fructans to obtain fructooligosaccharides. The thriving market for fructose syrup and the quality standards imposed by food and pharmaceutical industries have [...] Read more.

The yeast Kluyveromyces marxianus has shown the potential to produce

β

-fructofuranosidases, which are enzymes capable of hydrolyzing

β

-fructofuranosides links of fructans to obtain fructooligosaccharides. The thriving market for fructose syrup and the quality standards imposed by food and pharmaceutical industries have generated an increased search for improved, monitored, and controlled production processes. Monitoring

β

-fructofuranosidase activity in a bioprocess requires the use of adequate sensors and the processing of information using efficient software algorithms; nevertheless, currently, such a sensor does not exist for this purpose. In this contribution, a sequential injection analysis system (SIA) developed in our laboratory was adapted to monitor at-line

β

-fructofuranosidase activity produced by the yeast K. marxianus. Samples were taken out automatically from the bioreactor and analyzed using 3,5-dinitrosalicylic (DNS). An algorithm was designed to operate the overall components of the lab-made SIA system. The enzymatic activity error obtained with the automatic SIA compared to the off-line laboratory determinations varied from 0.07% at high enzyme concentrations to 20.39% at low

β

-fructofuranosidase activity. Further development is required to improve the performance of the lab-made SIA system; nevertheless, such a device must be considered as a potential method for monitoring

β

-fructofuranosidase activity in real time. Full article

(This article belongs to the Special Issue Fermentation Processes: Modeling, Optimization and Control)

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15 pages, 931 KiB

Open AccessEditor’s ChoiceArticle

Oxidative Phosphorylation for Aerobic Survival, but Not for Growth: The Peculiar ‘Make-Accumulate-Consume’ Strategy in Zymomonas mobilis

by Inese Strazdina, Mara Bikerniece, Evelina Rezija Paegle, Karlis Shvirksts, Mara Grube, Zane Lasa, Reinis Rutkis and Uldis Kalnenieks

Fermentation 2023, 9(11), 951; https://doi.org/10.3390/fermentation9110951 - 2 Nov 2023

Viewed by 1626

Abstract

Understanding the energy metabolism and its regulation is one of the clues to metabolic engineering of stress-resistant lignocellulose-converting microbial strains, also including the promising ethanologen Zymomonas mobilis. Z. mobilis is an obligately fermentative, facultatively anaerobic bacterium, carrying an active respiratory chain with [...] Read more.

Understanding the energy metabolism and its regulation is one of the clues to metabolic engineering of stress-resistant lignocellulose-converting microbial strains, also including the promising ethanologen Zymomonas mobilis. Z. mobilis is an obligately fermentative, facultatively anaerobic bacterium, carrying an active respiratory chain with low energy-coupling efficiency. Its respiration does not supply energy to aerobically growing cultures on sugary media, yet oxidative phosphorylation has been demonstrated in non-growing cells with ethanol. Here, we show, for the first time, that in respiring, non-growing Z. mobilis cells receiving regular small amounts of ethanol, oxidative phosphorylation significantly contributes to the maintenance of their viability. No improvement of viability is seen in the NADH dehydrogenase (ndh)-deficient respiratory mutant, which is unable to oxidize ethanol. The ethanol effect is also hampered by the protonophoric uncoupler CCCP, or the inhibitor of ATP synthase, DCCD. At higher concentrations (6% v/v), ethanol causes stress that slows down culture growth. By monitoring the activity of several respiratory gene promoters under ethanol stress with the green fluorescent protein reporter system, we demonstrate downregulation of these promoters, in particular the ndh promoter. We speculate that the decrease in respiratory chain activity in response to stress conditions mitigates the production of reactive oxygen species. Full article

(This article belongs to the Special Issue Bioconversion of Lignocellulosic Materials to Value-Added Products 2.0)

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17 pages, 6154 KiB

Open AccessEditor’s ChoiceArticle

Innocell Bioreactor: An Open-Source Development to Produce Biomaterials for Food and Packaging Based on Fermentation Processes

by Nitzan Cohen, Emma Sicher, Camilo Ayala-Garcia, Ignacio Merino Sanchez-Fayos, Lorenza Conterno and Secil Ugur Yavuz

Fermentation 2023, 9(10), 915; https://doi.org/10.3390/fermentation9100915 - 18 Oct 2023

Cited by 1 | Viewed by 4187

Abstract

A growing number of science and design scholars and design practitioners have recently embarked on studying fermentation processes to produce alternative materials. The main driver of this trend is the search for a sustainable future by proposing novel alternatives that could substitute or [...] Read more.

A growing number of science and design scholars and design practitioners have recently embarked on studying fermentation processes to produce alternative materials. The main driver of this trend is the search for a sustainable future by proposing novel alternatives that could substitute or integrate into society’s current production and consumption models. This study presents the development of an open-source bioreactor capable of enhancing and optimizing a symbiotic culture of bacteria and yeast (SCOBY) production process. The bioreactor is part of a greater design-driven project aiming to process edible and non-edible materials. The study presents the experiments and methods that led to the development and refinement of the current bioreactor, and all the information needed to replicate it with tools and equipment currently available under the Creative Commons status. The aim of sharing open-source methods and results to reproduce the bioreactor is to support different interdisciplinary teams of scientists and designers in generating high amounts of SCOBY, accelerating R&D with this auspicious yet underexplored source of bacterial cellulose. Full article

(This article belongs to the Special Issue Modeling Methods for Fermentation Processes)

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12 pages, 11523 KiB

Open AccessEditor’s ChoiceArticle

Engineering the C3N Pathway as a Short Detour for De Novo NAD⁺ Biosynthesis in Saccharomyces cerevisiae

by Xinli Li, Yue Tang, Yong Ding, Pengwei Li and Yihua Chen

Fermentation 2023, 9(10), 886; https://doi.org/10.3390/fermentation9100886 - 29 Sep 2023

Viewed by 1585

Abstract

As a life-essential coenzyme, nicotinamide adenine dinucleotide (NAD⁺) has been explored for more than a century. In Saccharomyces, the natural NAD⁺de novo biosynthetic pathway initiating from tryptophan has been well elucidated. To bypass this stringently controlled natural pathway [...] Read more.

As a life-essential coenzyme, nicotinamide adenine dinucleotide (NAD⁺) has been explored for more than a century. In Saccharomyces, the natural NAD⁺de novo biosynthetic pathway initiating from tryptophan has been well elucidated. To bypass this stringently controlled natural pathway in yeast, an economical C3N pathway that was developed in Escherichia coli previously was constructed in Saccharomyces as a short detour for de novo NAD⁺ biosynthesis. After the functional expressions of the C3N genes were identified in Saccharomyces cerevisiae BY4741 by in vitro enzymatic assays, the C3N module was introduced into an NAD⁺ auxotrophic S. cerevisiae strain BY01, in which the BNA2 gene encoding tryptophan 2,3-dioxygenase was inactivated. The efficient NAD⁺ synthesis via the C3N pathway was confirmed by both plate assays and fermentation analysis. The applicability of the C3N pathway in cofactor engineering was tested by introducing it into S. cerevisiae BY4741, which improved the cellular NAD(H) level considerably. Consequently, this study proved that the de novo NAD⁺ biosynthetic pathway can be replaced by an artificial pathway in yeast, which paves a way to design more promising schemes in eukaryotes for rational manipulation of the cellular NAD(H) levels. Full article

(This article belongs to the Special Issue Research on Microbial Transformation and Biosynthesis of Enzymes)

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18 pages, 1478 KiB

Open AccessEditor’s ChoiceArticle

Exploitation of Cocoa Pod Residues for the Production of Antioxidants, Polyhydroxyalkanoates, and Ethanol

by Licelander Hennessey Ramos, Miluska Cisneros-Yupanqui, Diana Vanessa Santisteban Soto, Anna Lante, Lorenzo Favaro, Sergio Casella and Marina Basaglia

Fermentation 2023, 9(9), 843; https://doi.org/10.3390/fermentation9090843 - 14 Sep 2023

Cited by 7 | Viewed by 2738

Abstract

Cocoa pod husks (CPH) and cocoa bean shells (CBS) are the main by-products of the cocoa industry and a source of bioactive compounds. These residues are not completely used and thrown in the fields without any treatment, causing environmental problems. Looking for a [...] Read more.

Cocoa pod husks (CPH) and cocoa bean shells (CBS) are the main by-products of the cocoa industry and a source of bioactive compounds. These residues are not completely used and thrown in the fields without any treatment, causing environmental problems. Looking for a holistic valorization, the aim of this work was first to deeply characterize CPH and CBS in their chemical composition, amino acid, and fatty acid profiles, as well as their application as antioxidants. CBS had a high level of protein (17.98% DM) and lipids (16.24% DM) compared with CPH (4.79 and 0.35% DM respectively). Glutamic acid and aspartic acid were the predominant amino acids. The total phenolic compounds (TPC) detected in the ethanolic extracts of CPH and CBS were similar to pyrogallol as the main detected polyphenol (72.57 mg/L). CBS ethanolic extract showed a higher antioxidant activity than CPH. Both extracts increased the oxidation stability of soybean oil by 48% (CPH) and 32% (CBS). In addition, alkaline pretreatment of CPH was found suitable for the release of 15.52 ± 0.78 g glucose/L after subsequent saccharification with the commercial enzyme Cellic^®. CTec2. Alkaline hydrolyzed and saccharified CPH (Ahs-CPH) was assessed for the first time to obtain polyhydroxy alkanoate (PHAs) and bioethanol. Ahs-CPH allowed the growth of both Cupriavidus necator DSM 545 and Saccharomyces cerevisiae Fm17, well-known as PHA- and bioethanol-producing microbes, respectively. The obtained results suggest that such agricultural wastes have interesting characteristics with new potential industrial uses that could be a better alternative for the utilization of biomass generated as million tons of waste annually. Full article

(This article belongs to the Special Issue Sustainable Development of Food Waste Biorefineries)

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17 pages, 3408 KiB

Open AccessEditor’s ChoiceArticle

Acetate Production by Moorella thermoacetica via Syngas Fermentation: Effect of Yeast Extract and Syngas Composition

by Budi Mandra Harahap and Birgitte K. Ahring

Fermentation 2023, 9(9), 826; https://doi.org/10.3390/fermentation9090826 - 9 Sep 2023

Cited by 1 | Viewed by 1953

Abstract

Gasifiers produce a gaseous mixture of CO/CO₂/H₂, also known as synthesis gas (syngas), containing varying compositions and ratios depending on the lignocellulose material types, gasifier design, and gasification conditions. Different physicochemical and thermodynamic properties of each gas type in [...] Read more.

Gasifiers produce a gaseous mixture of CO/CO₂/H₂, also known as synthesis gas (syngas), containing varying compositions and ratios depending on the lignocellulose material types, gasifier design, and gasification conditions. Different physicochemical and thermodynamic properties of each gas type in the various syngas blends can influence syngas fermentation performance for the production of chemicals such as acetate. This study examined the effect of syngas composition (CO, CO/H₂, CO/CO₂/H₂, and CO/H₂) and its corresponding ratio on acetate production using Moorella thermoacetica, a thermophilic homoacetogen as the biocatalyst. We also investigated the effect of yeast extract addition for enhancing acetate production. A syngas fermentation study performed at a total pressure of 19 psig (2.29 atm) demonstrated that syngas fermentation in the absence of CO (30%CO₂/70%H₂) or at low CO proportions (21%CO/24%CO₂/55%H₂) resulted in the highest volumetric productivity of acetate (0.046 ± 0.001 and 0.037 ± 0.001 g/L/h, respectively). Interestingly, syngas fermentation without CO reached the highest Y_P/X of 22.461 ± 0.574 g-acetate/g-biomass, indicating that more acetate was produced compared to cell biomass. Higher biomass production was obtained when the CO proportion was increased up to 75% in CO/H₂ fermentation. However, the cell growth and acetate production dramatically decreased with increasing CO proportion up to 99.5% CO as the sole constituent of the syngas. Even so, acetate production using 99.5% CO could be improved by adding 2 g/L yeast extract. Full article

(This article belongs to the Special Issue Recent Advances in Syngas Fermentation)

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16 pages, 1056 KiB

Open AccessEditor’s ChoiceArticle

Lactic Acid Production from Steam-Exploded Sugarcane Bagasse Using Bacillus coagulans DSM2314

by William Rodrigues Alves, Thiago Alessandre da Silva, Arion Zandoná Filho and Luiz Pereira Ramos

Fermentation 2023, 9(9), 789; https://doi.org/10.3390/fermentation9090789 - 26 Aug 2023

Cited by 5 | Viewed by 2434

Abstract

This work aimed at producing lactic acid (LA) from sugarcane bagasse after steam explosion at 195 °C for 7.5 and 15 min. Enzymatic hydrolysis was carried out with Cellic CTec3 and Cellic HTec3 (Novozymes), whereas fermentation was performed with Bacillus coagulans DSM2314. Water [...] Read more.

This work aimed at producing lactic acid (LA) from sugarcane bagasse after steam explosion at 195 °C for 7.5 and 15 min. Enzymatic hydrolysis was carried out with Cellic CTec3 and Cellic HTec3 (Novozymes), whereas fermentation was performed with Bacillus coagulans DSM2314. Water washing of pretreated solids before enzymatic hydrolysis improved both hydrolysis and fermentation yields. The presence of xylo-oligosaccharides (XOS) in substrate hydrolysates reduced hydrolysis efficiency, but their effect on fermentation was negligible. The presence of fermentation inhibitors in C5 streams was circumvented by adsorption on activated carbon powder with no detectable sugar losses. High carbohydrates-to-LA conversions (Y_p/s) of 0.88 g·g⁻¹ were obtained from enzymatic hydrolysates of water-washed steam-exploded materials that were produced at 195 °C, in 7.5 min, and the use of centrifuged-but-never-washed pretreated solids decreased Y_p/s by 16%. However, when the detoxified C5 stream was added at a 10% ratio, Y_p/s was raised to 0.93 g·g⁻¹ for an LA productivity of 2.55 g·L⁻¹·h⁻¹. Doubling the pretreatment time caused a decrease in Y_p/s to 0.78 g·g⁻¹, but LA productivity was the highest (3.20 g·L⁻¹·h⁻¹). For pretreatment at 195 °C for 7.5 min, the elimination of water washing seemed feasible, but the use of longer pretreatment times made it mandatory to eliminate fermentation inhibitors. Full article

(This article belongs to the Special Issue Upstream Bioprocesses to Biomass-Based Platform Chemicals and Derivatives)

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12 pages, 1247 KiB

Open AccessEditor’s ChoiceArticle

Evaluation of Long-Term Fermentation Performance with Engineered Saccharomyces cerevisiae Strains

by Maarten L. De Mol, Victoria Marcoen, Isabelle Maryns, Nico Snoeck, Joeri J. Beauprez, Sofie L. De Maeseneire and Wim K. Soetaert

Fermentation 2023, 9(8), 721; https://doi.org/10.3390/fermentation9080721 - 30 Jul 2023

Cited by 2 | Viewed by 2491

Abstract

The performance of a microbial fermentation on an industrial scale is subjected to the robustness of the strain. Such strains are genetically engineered to optimize the production of desired compounds in minimal time, but they often fail to maintain high productivity levels for [...] Read more.

The performance of a microbial fermentation on an industrial scale is subjected to the robustness of the strain. Such strains are genetically engineered to optimize the production of desired compounds in minimal time, but they often fail to maintain high productivity levels for many generations, hindering their effective application in industrial conditions. This study focused on assessing the impact of genomic instability in yeasts that were engineered to produce a fluorescent output by incorporating a reporter gene at one or more genomic locations. The fermentation performance of these strains was evaluated over 100 generations in a sequential batch set-up. In order to bridge the gap between strain engineering and industrial implementation, we proposed the use of novel, host-specific parameters to standardize the strain robustness and evaluate potential improvements. It was observed that yeasts carrying multiple copies of the reporter gene exhibited a more pronounced decrease in output, and the genomic integration site significantly influenced the production. By leveraging these new, host-specific parameters, it becomes possible to anticipate strain behavior prior to incurring substantial costs associated with large-scale production. This approach enhances the economic viability of novel microbial fermentation processes and narrows the divide between laboratory findings and industrial applications. Full article

(This article belongs to the Special Issue Modeling Methods for Fermentation Processes)

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12 pages, 1491 KiB

Open AccessEditor’s ChoiceArticle

Feasibility Study of Biohydrogen Production from Acid Cheese Whey via Lactate-Driven Dark Fermentation

by Brenda Aranda-Jaramillo, Elizabeth León-Becerril, Oscar Aguilar-Juárez, Roberto Castro-Muñoz and Octavio García-Depraect

Fermentation 2023, 9(7), 644; https://doi.org/10.3390/fermentation9070644 - 9 Jul 2023

Cited by 12 | Viewed by 3308

Abstract

The high loading of lactic acid bacteria (LAB) present in cheese whey still limits its use as hydrogen feedstock. This study aims to investigate the feasibility of producing hydrogen from acid cheese whey via lactate-driven dark fermentation (LD-DF). Mesophilic batch fermentations were performed [...] Read more.

The high loading of lactic acid bacteria (LAB) present in cheese whey still limits its use as hydrogen feedstock. This study aims to investigate the feasibility of producing hydrogen from acid cheese whey via lactate-driven dark fermentation (LD-DF). Mesophilic batch fermentations were performed with delipidated acid cheese whey at a fixed pH of 5.8 and driven by an acidogenic bacterial culture containing LAB and lactate-oxidizing hydrogen producers (LO-HPB). The results obtained indicated that it is technically feasible to produce hydrogen from undiluted cheese whey through lactate oxidation-mediated fermentation. It was elucidated that the acidogenic fermentation of cheese whey followed a two-step lactate-type fermentation, in which fermentable carbohydrates were first converted into lactate, and then lactate was metabolized into hydrogen with the co-production of butyrate. The hydrogen yield and the maximum volumetric hydrogen production rate achieved were 44.5 ± 2.9 NmL/g-COD_fed and 1.9 NL/L-d, respectively. Further microbial community analysis revealed that Lactobacillus, Clostridium, and Klebsiella were the dominant bacterial genera when the hydrogen production rate peaked. It was therefore suggested that the metabolic potential behind the association between LAB and LO-HPB was important in driving the two-step lactate-type fermentation. Overall, the LD-DF can be a strategic hydrogen-producing pathway to be implemented with cheese whey. Full article

(This article belongs to the Special Issue Organic Waste Valorization into Bioenergy and Biochemicals with High Industrial Interest)

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16 pages, 2498 KiB

Open AccessEditor’s ChoiceArticle

Effects of Temperature Shifts on Microbial Communities and Biogas Production: An In-Depth Comparison

by Gede Adi Wiguna Sudiartha, Tsuyoshi Imai, Chonticha Mamimin and Alissara Reungsang

Fermentation 2023, 9(7), 642; https://doi.org/10.3390/fermentation9070642 - 8 Jul 2023

Cited by 16 | Viewed by 2952

Abstract

Temperature plays a significant role in anaerobic digestion (AD) as it affects the microbial communities and ultimately controls the efficiency of the process. Few studies have looked at temperature-adjusted AD, but it is unclear how the temperature shifts affect biogas production and the [...] Read more.

Temperature plays a significant role in anaerobic digestion (AD) as it affects the microbial communities and ultimately controls the efficiency of the process. Few studies have looked at temperature-adjusted AD, but it is unclear how the temperature shifts affect biogas production and the dynamics of microorganisms involved in methanogenesis. This study tested two temperature shift scenarios in fed-batch mode using anaerobically digested sewage sludge and glucose-based substrate. The first scenario was acclimatized to upshifting temperatures from 42 °C to 48 °C while the second was acclimatized to downshifting temperatures from 55 °C to 45 °C. Both temperature shift scenarios resulted in a decrease in biogas production, especially at 45 °C. The upshifted scenario experienced a maximum decrease of 83%, and the downshifted scenario experienced a 16–33% decrease in methane production. Next-generation 16S rRNA sequencing revealed the domination of Methanoculleus in the upshifted scenario. However, a low correlation between the number of Methanoculleus and the other hydrogenotrophic methanogens to biogas production indicates inhibition in the hydrogenotrophic pathway. The downshifted scenario showed better biogas production due to the substantial domination of acetoclastic Methanosaeta and the low abundance of sulfate-reducing bacteria. Hence, the temperature shift affects the microbial communities, significantly affecting biogas production performance. Full article

(This article belongs to the Special Issue Anaerobic Digestion: Waste to Energy)

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19 pages, 2780 KiB

Open AccessEditor’s ChoiceArticle

Automatic Control of Chemolithotrophic Cultivation of Cupriavidus necator: Optimization of Oxygen Supply for Enhanced Bioplastic Production

by Vera Lambauer, Alexander Permann, Zdeněk Petrášek, Vanja Subotić, Christoph Hochenauer, Regina Kratzer and Markus Reichhartinger

Fermentation 2023, 9(7), 619; https://doi.org/10.3390/fermentation9070619 - 29 Jun 2023

Cited by 10 | Viewed by 3231

Abstract

Gas fermentation is an upcoming technology to convert gaseous substrates into value-added products using autotrophic microorganisms. The hydrogen-oxidizing bacteria Cupriavidus necator efficiently uses CO₂ as its sole carbon source, H₂ as electron donor and O₂ as electron acceptor. Surplus CO [...] Read more.

Gas fermentation is an upcoming technology to convert gaseous substrates into value-added products using autotrophic microorganisms. The hydrogen-oxidizing bacteria Cupriavidus necator efficiently uses CO₂ as its sole carbon source, H₂ as electron donor and O₂ as electron acceptor. Surplus CO₂ is stored in microbial storage material poly-(R)-3-hydroxybutyrate. O₂ supply is the most critical parameter for growth and poly-(R)-3-hydroxybutyrate formation. A narrow O₂ optimum between ~0.2 and ~4 mg/L was previously reported. Here, a standard benchtop bioreactor was redesigned for autotrophic growth of C. necator on explosive mixtures of CO₂, H₂ and O₂. The bioreactor was equipped with mass flow control units and O₂ and CO₂ sensors. A controller for automated gas dosage based on a mathematical model including gas mass transfer, gas consumption and sensor response time was developed. Dissolved O₂ concentrations were adjusted with high precision to 1, 2 and 4% O₂ saturation (0.4, 0.8 and 1.5 mg/L dissolved O₂, respectively). In total, up to 15 g/L cell dry weight were produced. Residual biomass formation was 3.6 ± 0.2 g/L under all three O₂ concentrations. However, poly-(R)-3-hydroxybutyrate content was 71, 77 and 58% of the cell dry weight with 1, 2 and 4% dissolved O₂, respectively. Full article

(This article belongs to the Special Issue Biomass Conversion, CO₂ Valorisation and Power-to-X: Fermentation Chemicals and Fuels)

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17 pages, 3639 KiB

Open AccessEditor’s ChoiceArticle

Lactic Acid Production from Cow Manure: Experimental Process Conditions Analysis

by Ricard Garrido, Víctor Falguera, Omar Pérez Navarro, Amanda Acosta Solares and Luisa F. Cabeza

Fermentation 2023, 9(7), 604; https://doi.org/10.3390/fermentation9070604 - 27 Jun 2023

Cited by 2 | Viewed by 2451

Abstract

The production of cow manure far exceeds the quantity that can be utilized in primary applications such as fertilizer or for the generation of biogas. As a result, alternative value-added applications are being investigated. The purpose of this study is to evaluate the [...] Read more.

The production of cow manure far exceeds the quantity that can be utilized in primary applications such as fertilizer or for the generation of biogas. As a result, alternative value-added applications are being investigated. The purpose of this study is to evaluate the production of lactic acid, using cow manure as the raw material. The methodology involved the implementation of thermochemical pretreatment for the cow manure, followed by simultaneous saccharification and fermentation for lactic acid production. Response surface methodology based on a central composite design was employed to analyze the simultaneous saccharification and fermentation process. The factorial design of the experiments was carried out with three factors, cow manure concentration, temperature, and enzyme concentration, with 80 g·L⁻¹, 50 °C, and 212.5 IU/gCM_{Dry Matter} as central point values, respectively. Following the addition of Bacillus coagulans DSM2314 inoculum to enzymatically hydrolyzed cow manure at pH 5.0, after a 24 h period the concentration of lactic acid was recorded at 13.65 g·L⁻¹, with a conversion efficiency of 33.1%. Studies were conducted until 48 h to analyze time impact. Characterization studies for native cow manure and that pretreated using acid reagent were conducted. Sugar content and by-product formation were analyzed, resulting in 23.24 g·L⁻¹ of sugar remaining as the maximum after fermentation, while low values of furfural (1.04 g·L⁻¹), 5-hydroxymethylfurfural (1.35 g·L⁻¹), and acetic acid (1.45 g·L⁻¹) were found. Optimal conditions were calculated at 24 and 48 h with R software, obtaining the lactic acid, with yields of 13.4 g·L⁻¹, 36.28% (for 24 h) and 15.27 g·L⁻¹, 32.76% (for 48 h), respectively. Experimental and statistical studies of enzymatic hydrolysis and fermentation stated that cow manure was a feasible substrate for the production of lactic acid. Full article

(This article belongs to the Special Issue Upstream Bioprocesses to Biomass-Based Platform Chemicals and Derivatives)

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14 pages, 2350 KiB

Open AccessEditor’s ChoiceArticle

Development of Blood Sugar Regulatory Products from Momordica cochininensis via Probiotic Fermentation

by Po-Hua Wu, Huei-Rong Guo, Yi-An Liu, Chien-Hui Wu, Chun-Chen Huang, Jer-An Lin and Chang-Wei Hsieh

Fermentation 2023, 9(6), 578; https://doi.org/10.3390/fermentation9060578 - 18 Jun 2023

Cited by 4 | Viewed by 2520

Abstract

Type II diabetes is the most important health issue in the whole world. Besides the use of prescribed drugs to control blood glucose level, recently, the development of health supplements is being actively explored. Owing to its high nutritional value, Momordica cochinchinensis Spreng. [...] Read more.

Type II diabetes is the most important health issue in the whole world. Besides the use of prescribed drugs to control blood glucose level, recently, the development of health supplements is being actively explored. Owing to its high nutritional value, Momordica cochinchinensis Spreng. (Gac) is potentially a good source for developing this supplement. In recent years, the aril of Gac has been utilized as a substrate for developing various forms of supplements, but the pulp has been neglected as a byproduct. However, the pulp contains lots of phytochemicals that could provide health benefits, and the investigation using lactobacilli to ferment the pulp juices to lower blood glucose is not yet to be explored. Therefore, we set out to investigate the potential to develop the pulp-based juices for controlling blood glucose level by selecting an optimal strain of lactobacillus to ferment the pulp juice and measuring the inhibitory action of the fermented juice on α-glucosidase. This enzyme is crucial for controlling postprandial glucose absorbed into the bloodstream because it is the enzyme that hydrolyzes the carbohydrates to release glucose. First, we have successfully isolated a strain of lactobacillus which was capable of fermenting the pulp to produce α-glucosidase-inhibitory activity. Through a 16S rRNA sequence, this lactobacillus was named Lactiplantibacillus plantarum GBI 001. The optimal conditions for its growth in commercial culture medium were found to be 35 °C for 16 h to produce the highest α-glucosidase activity (72.03%). The optimal conditions for the strain to grow in Gac pulp juice were: 20% pulp juices as substrate with an initial pH adjusted to 4.0, growing at 35 °C for 16 h. Under these conditions, the fermented juice exhibited α-glucosidase activity of 24.36%, which is a 2.17-fold increase over the control group (11.23%). From its increase in α-glucosidase potency, using L. plantarum GBI 001 to ferment the pulp juices of Gac as soft drinks has great potential to develop a helpful drink as a food supplement to control postprandial blood glucose in patients with diabetes. Full article

(This article belongs to the Special Issue The Rendering of Traditional Fermented Foods in Human Diet: Distribution of Health Benefits and Nutritional Benefits)

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12 pages, 1242 KiB

Open AccessEditor’s ChoiceArticle

Oral Administration of Animal and Plant Protein Mixture with Lactiplantibacillus plantarum IDCC 3501 Improves Protein Digestibility

by Hyeon Ji Jeon, Hayoung Kim, Minjee Lee, Jinseok Moon, Jungyeon Kim, Jungwoo Yang and Young Hoon Jung

Fermentation 2023, 9(6), 560; https://doi.org/10.3390/fermentation9060560 - 12 Jun 2023

Cited by 4 | Viewed by 2099

Abstract

A combined usage of animal and plant proteins-mixture could aid to solve environmental and social problems arising from the use of animal protein alone, while also improving the taste and texture of plant protein. Protein mixtures could be a better protein source due [...] Read more.

A combined usage of animal and plant proteins-mixture could aid to solve environmental and social problems arising from the use of animal protein alone, while also improving the taste and texture of plant protein. Protein mixtures could be a better protein source due to the high availability of amino acids in the body compared with single proteins. Consuming proteins with probiotics can provide more beneficial health effects by helping to hydrolyze protein and absorb amino acids in the body. In this study, coadministration of an animal and plant protein mixture with a high concentration of probiotics was investigated to increase protein digestibility and amino acids absorbability in a mice model. Lactiplantibacillus plantarum IDCC 3501, which has the maximum ability to hydrolyze a protein mixture, composed of soybean protein and milk protein, was selected, and the changes in mice (C57BL/6J, male, six weeks) were investigated after the coadministration of protein mixture and 5 × 10⁸ or 5 × 10⁹ CFU/mL of L. plantarum for eight weeks. Normal diet, high-protein diet (HPD), and HPD supplementing L. plantarum were separately administered to mice. Food and water consumption of the mice did not differ depending on diet type. Measurements of the serum concentrations of amino acids showed that the absorption of aspartate, glutamate, isoleucine, leucine, valine, and lysine increased when high concentrations of protein and probiotics were administered. Thus, high L. plantarum concentrations could be a protein diet supplementation to improve health by promoting the absorption of amino acids. Full article

(This article belongs to the Special Issue Recent Trends in Probiotics and Gut Microbiome for Human Health)

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14 pages, 4512 KiB

Open AccessEditor’s ChoiceArticle

Exopolysaccharide from Lactiplantibacillus plantarum YT013 and Its Apoptotic Activity on Gastric Cancer AGS Cells

by Rentao Zhang, Zhongkun Zhou, Yunhao Ma, Kangjia Du, Mengze Sun, Hao Zhang, Hongyuan Tu, Xinrong Jiang, Juan Lu, Lixue Tu, Yuqing Niu and Peng Chen

Fermentation 2023, 9(6), 539; https://doi.org/10.3390/fermentation9060539 - 31 May 2023

Cited by 2 | Viewed by 1943

Abstract

Cancer is a significant health burden in the world. Natural product drugs have received widespread attention because of their safety and effectiveness, stable effects and fewer side effects. Some studies have demonstrated that exopolysaccharide (EPS) from lactic acid bacteria (LAB) can inhibit the [...] Read more.

Cancer is a significant health burden in the world. Natural product drugs have received widespread attention because of their safety and effectiveness, stable effects and fewer side effects. Some studies have demonstrated that exopolysaccharide (EPS) from lactic acid bacteria (LAB) can inhibit the growth of many types of cancer cells. In this work, the effects of the EPS from Lactiplantibacillus plantarum YT013 on gastric cancer cells were investigated. Its cytotoxicity was evaluated by MTT assay; at the concentration of 1000 μg/mL, the most significant inhibitory effect occurred in AGS cells, followed by SGC-7901, PANC-1 and HCT116, and less inhibited in HepG2 cells. Cell cycle results showed that EPS prevented AGS cells from transitioning from the S phase to the G₂/M phase. In addition, the results of flow cytometry showed that EPS promoted apoptosis in a concentration-dependent manner. Western blotting also indicated that EPS might lead to apoptosis via the endogenous mitochondrial apoptotic pathway. The safety of lyophilized powder, cell-free culture supernatant and EPS from Lactiplantibacillus plantarum YT013 were evaluated by observing tissue organs through H&E staining, and the results showed that the components were safe and effective and could provide a basis for the development of natural anticancer active drugs. Full article

(This article belongs to the Special Issue Role of Probiotics in Food Fermentation and Their Health Benefits)

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14 pages, 882 KiB

Open AccessEditor’s ChoiceArticle

Enhancement of Bioactive Properties in Momordica charantia by Leuconostoc Fermentation

by Jiwoo Kim, Sungryul Yu, Yoonhwa Jeong and Misook Kim

Fermentation 2023, 9(6), 523; https://doi.org/10.3390/fermentation9060523 - 29 May 2023

Cited by 7 | Viewed by 1864

Abstract

Momordica charantia (MC; commonly known as bitter melon) was fermented with Leuconostoc mesenteroides MKJW, MKSR, and KCTC 3719 (LM), and Leuconosoc citreum KCTC 3526 (LC), and their anti-diabetic, anti-dementia, and antioxidant activities were evaluated. The fermentation was performed for 24 h at 30 [...] Read more.

Momordica charantia (MC; commonly known as bitter melon) was fermented with Leuconostoc mesenteroides MKJW, MKSR, and KCTC 3719 (LM), and Leuconosoc citreum KCTC 3526 (LC), and their anti-diabetic, anti-dementia, and antioxidant activities were evaluated. The fermentation was performed for 24 h at 30 °C, and non-fermented MCs (CON1 and CON2) were included for comparison. All fermented MCs produced lactic acids, mannitol, dextran, and oligosaccharides. The highest amount of mannitol (34.76 mg/mL) and lactic acids (10.42 mg/mL) were produced in MKSR-MC, and the highest amount of dextran (22.37%) was produced in MKJW-MC. MKSR-MC showed complete α-glucosidase inhibition (99.91%), but it did not show a significant change in α-amylase inhibition (24.43%) compared to non-fermented MC (20.14%) (p > 0.05). It was also high in acetylcholinesterase inhibition (55.24%) compared to other fermented MCs (31.21–44.46%). Fermentation increased butyrylcholinesterase inhibition, but no significant differences were observed among the groups. Therefore, our results indicated that MKSR-fermented MC might be used as a non-dairy probiotic plant extract to achieve multi-health functional activities such as anti-diabetic, anti-dementia, and antioxidant activities. Full article

(This article belongs to the Special Issue Health and Bioactive Compounds of Fermented Foods and By-Products)

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14 pages, 3360 KiB

Open AccessEditor’s ChoiceArticle

The Effect of pH on the Production and Composition of Short- and Medium-Chain Fatty Acids from Food Waste in a Leachate Bed Reactor at Room Temperature

by Pooja Radadiya, Ashika Latika, Xunchang Fei, Jangho Lee, Saurabh Mishra and Abid Hussain

Fermentation 2023, 9(6), 518; https://doi.org/10.3390/fermentation9060518 - 27 May 2023

Cited by 1 | Viewed by 2141

Abstract

This study evaluated the hydrolysis and acidogenesis of food waste at different operating pHs (uncontrolled, 5.5, 6.5, 7.5, 8.5) in a leachate bed reactor (LBR) at room temperature. LBR operation at pH 6.5–8.5 resulted in a hydrolysis yield of 718–729 g SCOD/kg VS [...] Read more.

This study evaluated the hydrolysis and acidogenesis of food waste at different operating pHs (uncontrolled, 5.5, 6.5, 7.5, 8.5) in a leachate bed reactor (LBR) at room temperature. LBR operation at pH 6.5–8.5 resulted in a hydrolysis yield of 718–729 g SCOD/kg VS_added, which was statistically (p ≤ 0.05) higher than that obtained at pH 5.5 (577 g SCOD/kg VS_added) and the uncontrolled pH (462 g SCOD/kg VS_added). The hydrolysis rate at pH 6.5 was the highest amongst all the pH values. Stabilization at pH at 6.5 also resulted in a high fatty acid (FA) yield of 643 g COD_FA/kg VS_added. Butyrate was the main FA at the pH of 5.5–6.5, while acetate was the main FA at the pH of 7.5–8.5. At the uncontrolled pH, lactate production was the highest, indicating a shift in the microbial community from fatty-acid-producing bacteria to lactate-producing bacteria. The compositions of medium-chain fatty acids, such as caproate, were the highest at pH of 5.5. Full article

(This article belongs to the Special Issue Sustainable Development of Food Waste Biorefineries)

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13 pages, 1668 KiB

Open AccessEditor’s ChoiceArticle

Metagenomic and Meta-Transcriptomic Analysis Reveal the Colonization and Expression Profile of Probiotic Strains in Humans and Animals

by Yunjuan Peng, Routing Chen, Zhihao Zhang, Rui Jin, Ting Xie, Xinting Liu, Jianmin Chai, Samantha Howe, Jiangchao Zhao, Ying Li and Feilong Deng

Fermentation 2023, 9(5), 417; https://doi.org/10.3390/fermentation9050417 - 26 Apr 2023

Cited by 2 | Viewed by 2359

Abstract

In humans and animals, probiotics are widely accepted as crucial for host health and growth. The investigation of the probiotic colonization and expression of probiotics in the host is beneficial for proper usage of probiotics and isolation of indigenous probiotics. In this study, [...] Read more.

In humans and animals, probiotics are widely accepted as crucial for host health and growth. The investigation of the probiotic colonization and expression of probiotics in the host is beneficial for proper usage of probiotics and isolation of indigenous probiotics. In this study, we analyzed commonly used probiotic strains in the intestines/rumen of humans and animals by analyzing metagenomic and paired meta-transcriptomic data from the gut or rumen microbiome of humans (n = 13), pigs (n = 6), chickens (n = 6), cattle (n = 14), sheep (n = 10), and mice (n = 8). First, we generated an expression profile based on 192 selected representative probiotic strains from a published database. A total of 58 probiotic strains were not detected in any samples, while 3 strains were presented and expressed in all individuals. Overall, the probiotic expression of probiotics as detected by meta-transcriptome was significantly higher than the relative abundance of probiotic as detected by metagenomics in cattle, sheep, mice, and humans; however, this difference was not significant in pigs and chickens. In total, 17 (cattle), 21 (sheep), 22 (pig), 14 (chicken), 13 (mouse), and 3 (human) probiotic strains were identified as probiotic strains with significantly higher expression levels [Fold Change (FC) ≥ 2, False Discovery Rate (FDR) ≤ 0.05]. Among them, Clostridium butyricum TOA was found to be significantly expressed in the rumen or gut of all host species. In addition, network analysis based on the expression of probiotics as detected by meta-transcriptomics revealed that several probiotic strains were significantly negatively linked with Salmonella spp., Mycoplasma spp., and Escherichia coli. The results in this study provide a useful reference for developing indigenous probiotics. Full article

(This article belongs to the Special Issue Probiotics: Mediators in Health and Disease)

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14 pages, 1536 KiB

Open AccessEditor’s ChoiceArticle

Dynamics of Microbial Communities in Nitrite-Free and Nutritionally Improved Dry Fermented Sausages

by Núria Ferrer-Bustins, Belén Martín, Mar Llauger, Ricard Bou, Sara Bover-Cid and Anna Jofré

Fermentation 2023, 9(4), 403; https://doi.org/10.3390/fermentation9040403 - 21 Apr 2023

Cited by 5 | Viewed by 2117

Abstract

Dry fermented sausage innovation trends are linked to consumer preferences for clean label and sodium-reduced foods. This study aims to evaluate the effect of the formulation and production process temperature on the dynamics of bacterial communities in fuet-type dry fermented sausages using metataxonomics. [...] Read more.

Dry fermented sausage innovation trends are linked to consumer preferences for clean label and sodium-reduced foods. This study aims to evaluate the effect of the formulation and production process temperature on the dynamics of bacterial communities in fuet-type dry fermented sausages using metataxonomics. Six fuet batches were manufactured, including formulations without and with the addition of nitrifying salts (replaced or not by pork liver auto-hydrolysate as a colouring agent), processed at 3 to 12 °C, and a partial replacement of NaCl by KCl, processed at 12 °C. Fermentation was performed spontaneously or by a starter culture. Physicochemical characterisation and culture-dependent and independent bacterial analyses were performed at day 0, 4 and 12, at the end of ripening (a_w < 0.90) and after storage. Temperature was the most important factor determining the change in pH, a_w and lactic acid bacteria levels while the presence of a starter culture promoted a pH decrease. Metataxonomic analysis showed that low temperature processes and the absence of nitrifying salts allowed the growth of spoilage-related species, while sausages submitted to a mild temperature containing a starter culture and nitrifying salts showed less bacterial diversity. Liver auto-hydrolysate added putative probiotic species to the product. This study provides valuable information to manufacturers who want to innovate safely. Full article

(This article belongs to the Special Issue Perspectives on Microbiota of Fermented Foods)

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12 pages, 1626 KiB

Open AccessEditor’s ChoiceArticle

Fermentation of Corn By-Products: From Agrifood Waste to Higher Value Antioxidant Products

by Federica Tonolo, Alessandra Folda, Stefania Ferro, Roberta Seraglia, Angiolella Lombardi, Christian Andrighetto, Alessia Giannoni, Oriano Marin and Maria Pia Rigobello

Fermentation 2023, 9(4), 373; https://doi.org/10.3390/fermentation9040373 - 13 Apr 2023

Cited by 1 | Viewed by 2695

Abstract

To improve the nutri-functional quality and, in particular, the antioxidant capacity of corn by-products, fermentation with selected lactic acid bacteria was carried out. To this purpose, white-1 and 2 and yellow corn by-products were fermented and then extracted. In all the samples, the [...] Read more.

To improve the nutri-functional quality and, in particular, the antioxidant capacity of corn by-products, fermentation with selected lactic acid bacteria was carried out. To this purpose, white-1 and 2 and yellow corn by-products were fermented and then extracted. In all the samples, the fermentation process shows an improvement in antioxidant activity in comparison to non-fermented by-products. It was observed that the yellow corn by-product extracts have a higher content of total phenols, especially after fermentation with P. pentosaceus, while for white-1 corn by-product extracts, an increment of antioxidant capability was noticed when fermented with L. plantarum. The antioxidant capacity was measured with DPPH and ABTS⁺ assays, showing that yellow corn extracts are more active in comparison with white-1 and white-2 ones. Moreover, L. plantarum and P. pentosaceus provided the best results in increasing the antioxidant activity in all the samples. Analyzing lipid peroxidation in the presence of fermented white-2 corn by-product extracts, we observed an inhibition of the process after treatment with L. citreum compared to the non-fermented control. In all the analyzed samples, through LC-DAD-ESI/MS analysis, the antioxidant dicoumaroyl spermidine (DCS) was detected. The abundance of antioxidant molecules was higher in samples fermented with P. pentosaceus, confirming previous observations. Full article

(This article belongs to the Special Issue The Role of Antioxidant Compounds in Fermented Foods)

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30 pages, 5986 KiB

Open AccessEditor’s ChoiceArticle

Screening and Application of Novel Homofermentative Lactic Acid Bacteria Results in Low-FODMAP Whole-Wheat Bread

by Małgorzata Borowska, Lilit Ispiryan, Emma Neylon, Aylin W. Sahin, Craig P. Murphy, Emanuele Zannini, Elke K. Arendt and Aidan Coffey

Fermentation 2023, 9(4), 336; https://doi.org/10.3390/fermentation9040336 - 28 Mar 2023

Cited by 2 | Viewed by 3388

Abstract

FODMAPs are fermentable oligo-, di-, monosaccharides, and polyols. The application of homofermentative lactic acid bacteria (LAB) has been investigated as a promising approach for producing low-FODMAP whole-wheat bread. The low-FODMAP diet is recommended to treat irritable bowel syndrome (IBS). Wheat flour is staple [...] Read more.

FODMAPs are fermentable oligo-, di-, monosaccharides, and polyols. The application of homofermentative lactic acid bacteria (LAB) has been investigated as a promising approach for producing low-FODMAP whole-wheat bread. The low-FODMAP diet is recommended to treat irritable bowel syndrome (IBS). Wheat flour is staple to many diets and is a significant source of fructans, which are considered FODMAPs. The reduction of fructans via sourdough fermentation, generally associated with heterofermentative lactic acid bacteria (LAB), often leads to the accumulation of other FODMAPs. A collection of 244 wild-type LAB strains was isolated from different environments and their specific FODMAP utilisation profiles established. Three homofermentative strains were selected for production of whole-wheat sourdough bread. These were Lactiplantibacillus plantarum FST1.7 (FST1.7), Lacticaseibacillus paracasei R3 (R3), and Pediococcus pentosaceus RYE106 (RYE106). Carbohydrate levels in flour, sourdoughs (before and after 48 h fermentation), and resulting breads were analysed via HPAEC-PAD and compared with whole-wheat bread leavened with baker’s yeast. While strain R3 was the most efficient in FODMAP reduction, breads produced with all three test strains had FODMAP content below cut-off levels that would trigger IBS symptoms. Results of this study highlighted the potential of homofermentative LAB in producing low-FODMAP whole-wheat bread. Full article

(This article belongs to the Special Issue Functional Characterization of Lactic Acid Bacteria Isolated from Fermented Foods and Beverages)

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14 pages, 2605 KiB

Open AccessEditor’s ChoiceArticle

Chemical and Aromatic Changes during Fermentation of Kombucha Beverages Produced Using Strawberry Tree (Arbutus unedo) Fruits

by Eva Tejedor-Calvo and Diego Morales

Fermentation 2023, 9(4), 326; https://doi.org/10.3390/fermentation9040326 - 25 Mar 2023

Cited by 12 | Viewed by 4530

Abstract

The use of alternative ingredients in the production of kombucha has seen a recent increase. Our research aimed to characterize the chemical, nutritional, microbial, and aromatic profiles of kombucha beverages prepared with strawberry tree (Arbutus unedo) fruits fermented with three different [...] Read more.

The use of alternative ingredients in the production of kombucha has seen a recent increase. Our research aimed to characterize the chemical, nutritional, microbial, and aromatic profiles of kombucha beverages prepared with strawberry tree (Arbutus unedo) fruits fermented with three different SCOBYs for 21 days. The analyses showed similar levels of microbiological groups (aerobic mesophilic microorganisms, lactic acid bacteria, acetic acid bacteria, and yeasts)among the SCOBYs used. The beverages studied displayed a decrease in pH value and carbohydrate content, and protein degradation was also observed as fermentation progressed. However, the increase in total phenolic compounds during the first week proved to be a point of interest. A total of 20 volatile organic compounds were detected, giving different sensory qualities to the beverages: higher ethanol, benzaldehyde-4-ethyl, or acetic acid depending on the SCOBY used. The results obtained indicated that strawberry tree kombucha might be an alternative beverage with notable nutritional and aromatic properties, with fermentation time and SCOBY composition being identified as crucial factors. Full article

(This article belongs to the Special Issue Nutritional Significance of Fermented Foods)

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