Fermentation

16 pages, 2201 KB

Open AccessEditor’s ChoiceArticle

Improving Aroma Complexity with Hanseniaspora spp.: Terpenes, Acetate Esters, and Safranal

by Juan Manuel del Fresno, Carlos Escott, Francisco Carrau, José Enrique Herbert-Pucheta, Cristian Vaquero, Carmen González and Antonio Morata

Fermentation 2022, 8(11), 654; https://doi.org/10.3390/fermentation8110654 - 19 Nov 2022

Cited by 17 | Viewed by 4397

Abstract

Hanseniaspora vineae and Hanseniaspora opuntiae are apiculate yeasts normally found on the skins of ripe grapes and at the beginning of alcoholic fermentation. Several studies have reported that these species can provide interesting sensory characteristics to wine by contributing high levels of acetate [...] Read more.

Hanseniaspora vineae and Hanseniaspora opuntiae are apiculate yeasts normally found on the skins of ripe grapes and at the beginning of alcoholic fermentation. Several studies have reported that these species can provide interesting sensory characteristics to wine by contributing high levels of acetate esters and can increase the mouthfeel and body of wines. The present work aims to evaluate the use of these two species sequentially with Saccharomyces cerevisiae to improve the sensory profile of Albillo Mayor white wines. The fermentations were carried out in triplicate in 150 L stainless steel barrels. At the end of the alcoholic fermentation polysaccharides, colour, and an extensive study of the aromatic profiles were measured. Results showed up to 1.55 times higher content of 2-phenylethanol in H. opuntiae wines and up to three times higher concentration of fermentative esters in H. vineae wines than in the controls. Interestingly, it should be noted that the compound safranal was identified only in the H. vineae wines. These results indicated that the species studied are an interesting bio-tool to improve the aromatic profile of Albillo Mayor white wines. A novel non-targeted NMR-based metabolomics approach is proposed as a tool for optimising wine productions with standard and sequential fermentation schemes using apiculate yeast strains due to its discriminant capacity to differentiate fine features between wine samples from the identical geographical origin and grape variety but diverse fermentations or vintages. Full article

(This article belongs to the Special Issue Enological Repercussions of Non-saccharomyces Species 4.0)

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11 pages, 1940 KB

Open AccessEditor’s ChoiceArticle

Anaerobic Co-Digestion of Bioplastics and Food Waste under Mesophilic and Thermophilic Conditions: Synergistic Effect and Biodegradation

by Jeong-Hee Kang, Sung-Won Kang, Weon-Jae Kim, Dong-Hoon Kim and Seong-Won Im

Fermentation 2022, 8(11), 638; https://doi.org/10.3390/fermentation8110638 - 14 Nov 2022

Cited by 23 | Viewed by 5034

Abstract

To mitigate the various problems caused by using conventional plastics, bioplastic (BP) has emerged as a substitute for plastics. BP wastes after use are commonly treated using composting, causing many environmental problems. Anaerobic digestion (AD) has become prominent as an alternative method of [...] Read more.

To mitigate the various problems caused by using conventional plastics, bioplastic (BP) has emerged as a substitute for plastics. BP wastes after use are commonly treated using composting, causing many environmental problems. Anaerobic digestion (AD) has become prominent as an alternative method of producing renewable energy. The aim of this study was to estimate the methane production yield (MPY) of BPs (polylactic acid (PLA) and polyhydroxyalkanoate (PHA)) with mechanical pretreatment (particle size < 0.5 cm) and investigate the effect of co-digestion of BPs and food waste (FW). Batch experiments were conducted under mesophilic and thermophilic conditions at various mixing ratios (FW/PLA or PHA = 95:5 and 90:10 on a weight basis). During 20 d of digestion at temperatures of 37 and 55 °C, MPYs of PHA were 153.8–172.0 mL CH₄/g chemical oxygen demand (COD), but that of PLA was significantly low (<25.6 mL CH₄/g COD). Higher MPYs were attained at 55 °C than at 37 °C. The synergistic effects of FW addition on BP AD were observed at both temperatures, especially at 55 °C. By comparing theoretical (based on mono-digestion results) and actual (based on co-digestion results) MPYs, the synergistic effect of FW addition on MPY of co-digestion reached 8.5–26.6% and 12.7–25.5% for PLA- and PHA-fed tests, respectively. The biodegradation rates (on a volatile solids (VS) basis) of PLA and PHA were 6.0–13.7% and 49.1–52.3% and increased by 1.8–4.3 and 1.2–1.5 times in the PLA- and PHA-fed co-digestion tests, respectively. Co-digestion of FW might be a feasible treatment option for BPs combined with simple mechanical pretreatment. Full article

(This article belongs to the Topic Waste-to-Energy)

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12 pages, 1318 KB

Open AccessEditor’s ChoiceArticle

Photosynthetic Carbon Uptake Correlates with Cell Protein Content during Lipid Accumulation in the Microalga Chlorella vulgaris NIES 227

by Paul Chambonniere, Adriana Ramírez-Romero, Alexandra Dimitriades-Lemaire, Jean-François Sassi and Florian Delrue

Fermentation 2022, 8(11), 614; https://doi.org/10.3390/fermentation8110614 - 8 Nov 2022

Cited by 15 | Viewed by 3773

Abstract

Large-scale microalgae cultivation for biofuel production is currently limited by the possibility of maintaining high microalgae yield and high lipid content, concomitantly. In this study, the physiological changes of Chlorella vulgaris NIES 227 during lipid accumulation under nutrient limitation was monitored in parallel [...] Read more.

Large-scale microalgae cultivation for biofuel production is currently limited by the possibility of maintaining high microalgae yield and high lipid content, concomitantly. In this study, the physiological changes of Chlorella vulgaris NIES 227 during lipid accumulation under nutrient limitation was monitored in parallel with the photosynthetic capacity of the microalgae to fix carbon from the proxy of oxygen productivity. In the exponential growth phase, as the biomass composition did not vary significantly (approx. 53.6 ± 7.8% protein, 6.64 ± 3.73% total lipids, and 26.0 ± 9.2% total carbohydrates of the total biomass dry-weight), the growth capacity of the microalgae was preserved (with net O₂ productivity remaining above (4.44 ± 0.93) × 10⁻⁷ g O₂·µmol PAR⁻¹). Under nutrient limitation, protein content decreased (minimum of approx. 18.6 ± 6.0%), and lipid content increased (lipid content up to 56.0 ± 0.8%). The physiological change of the microalgae was associated with a loss of photosynthetic activity, down to a minimum (1.27 ± 0.26) × 10⁻⁷ g O₂·µmol PAR⁻¹. The decrease in photosynthetic O₂ productivity was evidenced to correlate to the cell internal-protein content (R² = 0.632, p = 2.04 × 10⁻⁶, N = 25). This approach could serve to develop productivity models, with the aim of optimizing industrial processes. Full article

(This article belongs to the Special Issue Algal Biomass: From Bioproducts to Biofuels)

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18 pages, 2221 KB

Open AccessEditor’s ChoiceArticle

Probiotic Properties of Weissella confusa PP29 on Hibiscus sabdariffa L. Media

by Alexandra Dimofte, Natalia Simionescu, Anca-Roxana Petrovici and Iuliana Spiridon

Fermentation 2022, 8(10), 553; https://doi.org/10.3390/fermentation8100553 - 18 Oct 2022

Cited by 6 | Viewed by 3688

Abstract

To date, there are very few data regarding new efficient probiotics’ development with their own prebiotic substrate. All commercial products contain prebiotic substrate that was previously purified from external sources and added to the final product. The present study describes Weissella confusa strain [...] Read more.

To date, there are very few data regarding new efficient probiotics’ development with their own prebiotic substrate. All commercial products contain prebiotic substrate that was previously purified from external sources and added to the final product. The present study describes Weissella confusa strain fermentations in media with different anthocyanin concentrations from Hibiscus sabdariffa L., in order to increase the exopolysaccharide (EPS) yield, leading to augmented probiotic and prebiotic properties. The extracted and purified EPS were characterized by Gel permeation chromatography, Fourier-transform infrared, and nuclear magnetic resonance spectroscopy; thermal analysis measurements and the whole fermented media’s probiotic properties were evaluated by testing low pH and bile salt resistance, along with hydrophobicity and auto-aggregation capacity. The anthocyanins increased biomass and EPS yields and the high EPS molecular mass improved nutrient access by allowing a good microbial suspension in media. The confirmed dextran structure provides media biocompatibility and very good probiotic properties compared with existing literature. Simultaneously, the anthocyanins in media protected the strain cells against low pH and bile salt compared with the control fermentation. These very good results show that the whole fermented culture media is suitable for further in-vitro and in-vivo studies regarding its probiotic and prebiotic activity. Full article

(This article belongs to the Special Issue Postbiotics from Production to Their Health-Promoting Aspects)

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12 pages, 289 KB

Open AccessEditor’s ChoiceArticle

Evaluation of Different Brown Seaweeds as Feed and Feed Additives Regarding Rumen Fermentation and Methane Mitigation

by Eslam Ahmed, Belgutei Batbekh, Naoki Fukuma, Masaaki Hanada and Takehiro Nishida

Fermentation 2022, 8(10), 504; https://doi.org/10.3390/fermentation8100504 - 30 Sep 2022

Cited by 20 | Viewed by 4818

Abstract

This study investigated the impacts of different brown seaweed species—Ascophyllum nodosum, Sargassum fulvellum, Ecklonia maxima, Lessonia flavicans, Lessonia nigrescens, and Laminaria japonica—on rumen fermentation and methane (CH₄) mitigation. The current in vitro batch culture study [...] Read more.

This study investigated the impacts of different brown seaweed species—Ascophyllum nodosum, Sargassum fulvellum, Ecklonia maxima, Lessonia flavicans, Lessonia nigrescens, and Laminaria japonica—on rumen fermentation and methane (CH₄) mitigation. The current in vitro batch culture study for 24 h at 39 °C evaluated these species in two experimental designs: as feed additive and as feed. The control group for both experimental designs was composed of 500 mg of basal diet (50% grass hay/50% concentrate). For the feed additives experimental design, each seaweed species was evaluated when it was added at 20% of the basal diet, while as a feed, the inclusion level of each species was 20% to partially replace the concentrate in the basal diet as follows (50% hay/30% concentrate/20% seaweed). Chemical analyses showed that the seaweeds were characterized by a high fiber content and high amounts of minerals such as calcium, potassium, and phosphorus, while the protein content ranged within 7 and 13%. When they were applied as feed additives, they increased the production of volatile fatty acids, with L. japonica being the most effective; however, they failed to suppress CH₄ production. In contrast, their inclusion as a feed in the basal diet led to a significant reduction (p < 0.05) in CH₄, especially for E. maxima and L. japonica, by up to 18 and 21%, respectively, but this was associated with general inhibition of the rumen fermentation. Therefore, the tested seaweeds could be used as a source of minerals and as a feed additive to improve rumen fermentation, but without anti-methanogenic potential. Meanwhile, their inclusion as feed at 20% could reduce CH₄ production with an adverse effect on fermentation. Thus, further trials are needed to identify the appropriate inclusion level to achieve effective CH₄ reduction without any detrimental effects on rumen fermentation. Full article

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

23 pages, 2164 KB

Open AccessEditor’s ChoiceArticle

Fermented Brewers’ Spent Grain Containing Dextran and Oligosaccharides as Ingredient for Composite Wheat Bread and Its Impact on Gut Metabolome In Vitro

by Prabin Koirala, Alice Costantini, Henry N. Maina, Carlo Giuseppe Rizzello, Michela Verni, Valentina De Beni, Andrea Polo, Kati Katina, Raffaella Di Cagno and Rossana Coda

Fermentation 2022, 8(10), 487; https://doi.org/10.3390/fermentation8100487 - 27 Sep 2022

Cited by 22 | Viewed by 5385

Abstract

Brewers’ spent grain or BSG is a fiber and protein rich food-grade side stream that has remained underutilized due to its poor technological and sensory characteristics. In this study, BSG was fermented with Weissella confusa A16 in presence of sucrose to induce the [...] Read more.

Brewers’ spent grain or BSG is a fiber and protein rich food-grade side stream that has remained underutilized due to its poor technological and sensory characteristics. In this study, BSG was fermented with Weissella confusa A16 in presence of sucrose to induce the synthesis of dextran and maltosyl-isomaltooligosaccharides. Fermented BSG with or without the above polysaccharides was used as ingredient in wheat bread. Digestion of BSG breads was simulated in vitro with Simulator of Human Intestinal Microbial Ecosystem, and levels of fecal metabolites were analyzed. Enrichment of BSG breads with in situ dextran and maltosyl-isomaltooligosaccharides improved the baking quality compared to native BSG. Metabolism of free amino acids and synthesis of short chain fatty acids varied at different stages and parts of colon. The increase in butyric acid was similar in both the proximal and distal colon. In situ dextran and maltosyl-isomaltooligosaccharides, and higher content of proteins and fiber in BSG breads had a positive influence towards gut microbiota functionality. Along with several essential amino acids, an increase in amount of γ-aminobutyric acid was also observed after simulated digestion. BSG breads had a significant effect on the gut metabolome during in vitro digestion, showing increased production of microbial metabolites with potential health benefits. Full article

(This article belongs to the Special Issue Food Fermentation for Better Nutrition, Health and Sustainability)

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13 pages, 1447 KB

Open AccessEditor’s ChoiceArticle

The Biotransformation of Lupine Seeds by Lactic Acid Bacteria and Penicillium camemberti into a Plant-Based Camembert Alternative, and Its Physicochemical Changes during 7 Weeks of Ripening

by Łukasz Łopusiewcz, Natalia Śmietana, Elżbieta Lichwiarska, Kinga Mazurkiewicz-Zapałowicz, Annett Gefrom and Emilia Drozłowska

Fermentation 2022, 8(9), 447; https://doi.org/10.3390/fermentation8090447 - 8 Sep 2022

Cited by 8 | Viewed by 4340

Abstract

In recent years, there has been increasing consumer interest and research into plant-based dairy alternatives, due to the increasingly negative impact of animal products on human health, animal welfare, and the environment. The purpose of this study was to investigate the physicochemical and [...] Read more.

In recent years, there has been increasing consumer interest and research into plant-based dairy alternatives, due to the increasingly negative impact of animal products on human health, animal welfare, and the environment. The purpose of this study was to investigate the physicochemical and microbiological changes in a Camembert alternative based on the seeds of sweet lupine (Lupinus angustifolius L cv. ‘Boregine’). After heat treatment and homogenization, the seeds were incubated with lactic acid bacteria (LAB) and Penicillium camemberti mold. After fermentation at room temperature, the samples were stored at 12 °C for 14 days, and then ripened until day 49 at 6 °C. Changes in microbial population, acidity, texture, content of polyphenols, flavonoids, reducing sugars, and free amino acids were monitored. In addition, the antioxidant capacity of the samples during ripening was determined. The results showed that LAB and fungi were able to grow well in the lupine matrix. Initially, a decrease in pH was observed, while in the further stages of ripening, alkalization of the product linked with progressive proteolysis associated with an increase in free amino acid content was noted. Hydrolysis of polysaccharides and an increase in antioxidant activity were observed. This indicates the potential of lupine seeds as a raw material for the development of a new group of plant-based ripened cheese alternatives. Full article

(This article belongs to the Special Issue Biotransformation of Plant Materials by Molds and Higher Fungi)

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25 pages, 3962 KB

Open AccessEditor’s ChoiceArticle

Glycerol Utilization as a Sole Carbon Source Disrupts the Membrane Architecture and Solventogenesis in Clostridium beijerinckii NCIMB 8052

by Eric Agyeman-Duah, Santosh Kumar, Bhavana Gangwar and Victor C. Ujor

Fermentation 2022, 8(7), 339; https://doi.org/10.3390/fermentation8070339 - 19 Jul 2022

Cited by 12 | Viewed by 4188

Abstract

Efficient bioconversion of abundant waste glycerol to value-added chemicals calls for a wider range of fermentative workhorses that can catabolize glycerol. In this study, we used quantitative gene expression and solvent profiling, qualitative metabolite analysis, and enzyme activity assays to investigate the factors [...] Read more.

Efficient bioconversion of abundant waste glycerol to value-added chemicals calls for a wider range of fermentative workhorses that can catabolize glycerol. In this study, we used quantitative gene expression and solvent profiling, qualitative metabolite analysis, and enzyme activity assays to investigate the factors that limit glycerol utilization as a sole carbon source by Clostridium beijerinckii NCIMB 8052. C. beijerinckii NCIMB 8052 did not produce acetate, acetone and butanol on glycerol. Congruently, the genes encoding the coenzyme A transferase subunits (ctfAB) and bifunctional acetaldehyde-CoA/alcohol dehydrogenase (adhE) were down-regulated up to 135- and 21-fold, respectively, at 12 h in glycerol-grown cells compared to glucose-grown cells. Conversely, NADH-dependent butanol dehydrogenase A (bdhA) was upregulated 2-fold. Glycerol dehydrogenase (gldA) and dihydroxyacetone kinase (subunit dhaK) were upregulated up to 5- and 881-fold, respectively. Glyceraldehyde-3-phosphate dehydrogenase (gapdh) showed mostly similar expression profiles at 12 h on glucose and glycerol. At 24 h, gapdh was downregulated 1.5-fold, while NADP⁺-dependent gapdh was upregulated up to 1.9-fold. Glycerol-grown cells showed higher or similar activity profiles for all solventogenic enzymes studied, compared to glucose-grown cells. Butyraldehyde (3 g/L) supplementation led to the production of ~0.1 g/L butanol, whilst butyrate (3.5 g/L) supplementation produced 0.7 and 0.5 g/L acetone and butanol, respectively, with glycerol. Further, the long chain saturated fatty acids cyclopentaneundecanoic acid, methyl ester and hexadecanoic acid, butyl ester were detected in glucose- but not in glycerol-grown cells. Collectively, growth on glycerol appears to disrupt synthesis of saturated long chain fatty acids, as well as solventogenesis in C. beijerinckii NCIMB 8052. Full article

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

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13 pages, 1860 KB

Open AccessEditor’s ChoiceArticle

Evaluation and Identification of Key Economic Bottlenecks for Cost-Effective Microbial Oil Production from Fruit and Vegetable Residues

by María Gallego-García, Ana Susmozas, Antonio D. Moreno and María José Negro

Fermentation 2022, 8(7), 334; https://doi.org/10.3390/fermentation8070334 - 15 Jul 2022

Cited by 11 | Viewed by 4283

Abstract

Intensive horticultural systems for the production of vegetables in greenhouses represent one of the main industries generating organic waste, as those that do not meet the quality standards for the fresh market or the processing industry are discarded. This highlights the importance of [...] Read more.

Intensive horticultural systems for the production of vegetables in greenhouses represent one of the main industries generating organic waste, as those that do not meet the quality standards for the fresh market or the processing industry are discarded. This highlights the importance of using these residues as raw material for other applications, such as bioenergy and bioproducts production, within the framework of a bio-based economy that maximizes the utilization of biomass resources in a sustainable manner. In this work, the microbial oil production from discarded pepper using the oleaginous yeast Cryptococcus curvatus was evaluated. Overall, a total lipid accumulation of 16.8 g/L was achieved with a fatty acid profile suitable to produce biodiesel. The lipid yield obtained was 0.12 g/g sugars. In addition, experimental results were used to assess the techno-economic feasibility of a proposed microbial oil plant using the software Aspen Plus. This plant yields approximately 96 kg of microbial oils/ton dry discarded pepper, with an estimated Minimum Selling Price of 7 €·kg⁻¹. These figures point out the necessity of increasing the yield of microbial oil production and considering the utilization of possible by-products, such as mannitol and cell debris, to improve the economic performance of the process. Full article

(This article belongs to the Special Issue Fermentative Production of Biofuels and Bioproducts within a Biorefinery Perspective)

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15 pages, 1416 KB

Open AccessEditor’s ChoiceArticle

Hydrogen and Methane Production from Anaerobic Co-Digestion of Sorghum and Cow Manure: Effect of pH and Hydraulic Retention Time

by Margarita A. Dareioti, Konstantina Tsigkou, Aikaterini I. Vavouraki and Michael Kornaros

Fermentation 2022, 8(7), 304; https://doi.org/10.3390/fermentation8070304 - 27 Jun 2022

Cited by 28 | Viewed by 4476

Abstract

The need for alternative energy sources is constantly growing worldwide, while the focus has shifted to the valorization of biomass. The aim of the present study was to determine the optimal pH and hydraulic retention time (HRT) values for treating a mixture of [...] Read more.

The need for alternative energy sources is constantly growing worldwide, while the focus has shifted to the valorization of biomass. The aim of the present study was to determine the optimal pH and hydraulic retention time (HRT) values for treating a mixture of sorghum biomass solution with liquid cow manure (in a ratio 95:5 v/v) through anaerobic digestion, in a two-stage system. Batch tests were initially carried out for the investigation of the pH effect on bio-hydrogen and volatile fatty acids (VFA) production. The highest hydrogen yield of 0.92 mol H₂/mol carbohydrates_consumed was obtained at pH 5.0, whereas the maximum degradation of carbohydrates and VFA productivity was observed at pH 6.0. Further investigation of the effect of HRT on hydrogen and methane production was carried out. The maximum yield of 1.68 mol H₂/mol carbohydrates_consumed was observed at an HRT of 5 d, with H₂ productivity of 0.13 L/L_R·d. On the other hand, the highest CH₄ production rate of 0.44 L/L_R·d was achieved at an HRT of 25 d, with a methane yield of 295.3 mL/g VS_added, whereas at a reduced HRT of 20 d the process exhibited inhibition and/or overload, as indicated by an accumulation of VFAs and decline in CH₄ productivity. 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)

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22 pages, 2864 KB

Open AccessEditor’s ChoiceArticle

New Approaches for the Fermentation of Beer: Non-Saccharomyces Yeasts from Wine

by Vanesa Postigo, Ana Sánchez, Juan Mariano Cabellos and Teresa Arroyo

Fermentation 2022, 8(6), 280; https://doi.org/10.3390/fermentation8060280 - 15 Jun 2022

Cited by 40 | Viewed by 7516

Abstract

Non-Saccharomyces yeasts represent a very attractive alternative for the production of beers with superior sensory quality since they are able to enhance the flavour of beer. Furthermore, they can produce beers with low ethanol content due to the weak fermentative capacity of [...] Read more.

Non-Saccharomyces yeasts represent a very attractive alternative for the production of beers with superior sensory quality since they are able to enhance the flavour of beer. Furthermore, they can produce beers with low ethanol content due to the weak fermentative capacity of a large percentage of non-Saccharomyces species. The objective of this study was to evaluate the ability of 34 non-Saccharomyces yeast strains isolated from Madrilenian agriculture to produce a novel ale beer. The non-Saccharomyces yeast strains were screened at two scales in the laboratory. In the first screening, those with undesirable aromas were discarded and the selected strains were analysed. Thirty-three volatile compounds were analysed by GC, as well as melatonin production by HPLC, for the selected strains. Thirteen strains were then fermented at a higher scale in the laboratory for sensory evaluation. Only yeast strains of the species Schizosaccharomyces pombe and Lachancea thermotolerans were able to complete fermentation. Species such as Torulaspora delbrueckii, Metschnikowia pulcherrima, Wickerhamomyces anomalus, Hanseniaspora vineae, and Hanseniaspora guilliermondii could be used both for production of low ethanol beers and co-fermentation with a Saccharomyces yeast to improve the organoleptic characteristics of the beer. In addition, for these strains, the levels of melatonin obtained were higher than the concentrations found for Saccharomyces strains subjected to the same study conditions. The selected strains can be used in future trials to further determine their viability under different conditions and for different purposes. Full article

(This article belongs to the Special Issue Enological Repercussions of Non-saccharomyces Species 4.0)

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19 pages, 1871 KB

Open AccessEditor’s ChoiceArticle

Starmerella bacillaris Strains Used in Sequential Alcoholic Fermentation with Saccharomyces cerevisiae Improves Protein Stability in White Wines

by Luiza de Paula Dias Moreira, Chiara Nadai, Vinícius da Silva Duarte, Edward John Brearley-Smith, Matteo Marangon, Simone Vincenzi, Alessio Giacomini and Viviana Corich

Fermentation 2022, 8(6), 252; https://doi.org/10.3390/fermentation8060252 - 27 May 2022

Cited by 11 | Viewed by 4411

Abstract

Haze can appear in white wines as a result of the denaturation and subsequent aggregation of grape pathogenesis-related (PR) proteins. Yeast cell-wall polysaccharides, particularly mannoproteins, represent a promising strategy to reduce the incidence of this phenomenon. The aim of this study was to [...] Read more.

Haze can appear in white wines as a result of the denaturation and subsequent aggregation of grape pathogenesis-related (PR) proteins. Yeast cell-wall polysaccharides, particularly mannoproteins, represent a promising strategy to reduce the incidence of this phenomenon. The aim of this study was to evaluate the effects of 13 Starmerella bacillaris strains, in sequential fermentation with Saccharomyces cerevisiae, on wine protein stability of three white wines (Sauvignon blanc, Pinot grigio, and Manzoni bianco). The resulting wines were characterized in terms of their chemical composition, content of PR proteins and polysaccharides, and heat stability. In addition, the mannoprotein fraction was purified from six wines, five produced with S. bacillaris and one with S. cerevisiae EC1118 used as control. Generally, wines produced with S. bacillaris strains were more heat-stable, despite generally containing higher amounts of PR proteins. The increased heat stability of Starmerella wines was attributed to the stabilizing effect resulting from their higher concentrations of both total polysaccharides and mannoprotein fractions. In particular, for the most heat unstable wine (Manzoni bianco), the low MW mannoprotein fraction resulted to be the most involved in wine stability. The ability to produce wines with different heat stability was demonstrated to be strain-dependent and was more evident in the most unstable wines. By reducing fining waste, the use of S. bacillaris as an enological starter can be proposed as a new tool to manage wine protein stability for a more sustainable winemaking. Full article

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

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14 pages, 1258 KB

Open AccessEditor’s ChoiceArticle

Designing a Waste-Based Culture Medium for the Production of Plant Growth Promoting Microorganisms Based on Cladodes Juice from Opuntia ficus-indica Pruning

by Rosaria Alessandra Magarelli, Mario Trupo, Alfredo Ambrico, Vincenzo Larocca, Maria Martino, Salvatore Palazzo, Roberto Balducchi, Vesa Joutsjoki, Anne Pihlanto and Annamaria Bevivino

Fermentation 2022, 8(5), 225; https://doi.org/10.3390/fermentation8050225 - 14 May 2022

Cited by 16 | Viewed by 6112

Abstract

The production of beneficial microorganisms is the first step to obtain a commercial-based product for application in agriculture. In this study, prickly pear (Opuntia ficus-indica) pruning waste was evaluated as a raw material for the production of large amounts of Plant [...] Read more.

The production of beneficial microorganisms is the first step to obtain a commercial-based product for application in agriculture. In this study, prickly pear (Opuntia ficus-indica) pruning waste was evaluated as a raw material for the production of large amounts of Plant Growth Promoting Microorganisms (PGPMs) reducing the number of generated wastes. Specifically, five PGPMs constituting a synthetic microbial consortium with complementing plant growth-promoting traits were grown on a laboratory scale and, subsequently, on a pilot scale using a 21-L bioreactor. Primarily, the physical-chemical characterization of the culture medium obtained from the juice of Opuntia cladodes was carried out, revealing the presence of sugars and organic acids with different molar ratios. Compared to conventional media, the waste medium did not show significant differences in bacterial growth efficiency. Instead, the survival rates of the bacteria grown in cladodes juice media, after air-drying on zeolite or freeze-drying, were significantly higher than those observed when they were grown in conventional media. The present work is the first conducted on a pilot-scale that maximizes the production of PGPMs in submerged fermentation using cladodes juice from Opuntia, reducing both economic and environmental impacts associated with the generation of wastes. Full article

(This article belongs to the Collection Food Waste Valorization)

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14 pages, 3084 KB

Open AccessEditor’s ChoiceArticle

pH Auto-Sustain-Based Fermentation Supports Efficient Gamma-Aminobutyric Acid Production by Lactobacillus brevis CD0817

by Mengya Jia, Yisong Zhu, Lingqin Wang, Tianyi Sun, Hao Pan and Haixing Li

Fermentation 2022, 8(5), 208; https://doi.org/10.3390/fermentation8050208 - 3 May 2022

Cited by 34 | Viewed by 3975

Abstract

Gamma-aminobutyric acid (GABA) plays a role in several physiological functions. GABA production by lactic acid bacteria has attracted considerable interest; however, there is need to improve production. This study aimed to develop a pH auto-sustain (PAS)-based GABA fermentation process for Lactobacillus brevis CD0817, [...] Read more.

Gamma-aminobutyric acid (GABA) plays a role in several physiological functions. GABA production by lactic acid bacteria has attracted considerable interest; however, there is need to improve production. This study aimed to develop a pH auto-sustain (PAS)-based GABA fermentation process for Lactobacillus brevis CD0817, with L-glutamic acid (solubility ~6.0 g/L and isoelectric point 3.22) as the substrate. Firstly, we determined the optimum levels of vital factors affecting GABA synthesis using Erlenmeyer flask experiments. The results showed that optimal levels of sugar, yeast extract, Tween-80, manganese ion, and temperature were 5.0 g/L, 35.0 g/L, 1.0 g/L, 16.0 mg/L, and 30.0 °C, respectively. The added L-glutamic acid (650 g per liter of medium) mostly existed in the form of solid powder was slowly released to supply the substrate and acidity essential for GABA production with the progress of fermentation. Based on the optimizations, the PAS-based GABA fermentation was performed using a 10 L fermenter. The PAS-based strategy promoted GABA synthesis by the strain of up to 321.9 ± 6.7 g/L after 48 h, with a productivity of 6.71 g/L/h and a substrate molar conversion rate of 99.6%. The findings suggest that the PAS-based fermentation is a promising method for GABA production by lactic acid bacteria. Full article

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

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19 pages, 959 KB

Open AccessEditor’s ChoiceArticle

Recombinant Protein Production in E. coli Using the phoA Expression System

by Thomas Gundinger, Stefan Kittler, Sabine Kubicek, Julian Kopp and Oliver Spadiut

Fermentation 2022, 8(4), 181; https://doi.org/10.3390/fermentation8040181 - 11 Apr 2022

Cited by 16 | Viewed by 9762

Abstract

Auto-inducible promoter systems have been reported to increase soluble product formation in the periplasm of E. coli compared to inducer-dependent systems. In this study, we investigated the phosphate (PO₄)-sensitive phoA expression system (pAT) for the production of a recombinant model antigen-binding [...] Read more.

Auto-inducible promoter systems have been reported to increase soluble product formation in the periplasm of E. coli compared to inducer-dependent systems. In this study, we investigated the phosphate (PO₄)-sensitive phoA expression system (pAT) for the production of a recombinant model antigen-binding fragment (Fab) in the periplasm of E. coli in detail. We explored the impact of non-limiting and limiting PO₄ conditions on strain physiology as well as Fab productivity. We compared different methods for extracellular PO₄ detection, identifying automated colorimetric measurement to be most suitable for at-line PO₄ monitoring. We showed that PO₄ limitation boosts phoA-based gene expression, however, the product was already formed at non-limiting PO₄ conditions, indicating leaky expression. Furthermore, cultivation under PO₄ limitation caused physiological changes ultimately resulting in a metabolic breakdown at PO₄ starvation. Finally, we give recommendations for process optimization with the phoA expression system. In summary, our study provides very detailed information on the E. coli phoA expression system, thus extending the existing knowledge of this system, and underlines its high potential for the successful production of periplasmic products in E. coli. Full article

(This article belongs to the Section Fermentation Process Design)

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24 pages, 2987 KB

Open AccessEditor’s ChoiceArticle

Towards a Complete Exploitation of Brewers’ Spent Grain from a Circular Economy Perspective

by Chiara Allegretti, Emanuela Bellinetto, Paola D’Arrigo, Gianmarco Griffini, Stefano Marzorati, Letizia Anna Maria Rossato, Eleonora Ruffini, Luca Schiavi, Stefano Serra, Alberto Strini, Davide Tessaro and Stefano Turri

Fermentation 2022, 8(4), 151; https://doi.org/10.3390/fermentation8040151 - 29 Mar 2022

Cited by 26 | Viewed by 6872

Abstract

In the present work, brewers’ spent grain (BSG), which represents the major by-product of the brewing industry, was recovered from a regional brewery and fractionated in order to obtain a complete valorization. In particular, the whole process was divided in two main parts. [...] Read more.

In the present work, brewers’ spent grain (BSG), which represents the major by-product of the brewing industry, was recovered from a regional brewery and fractionated in order to obtain a complete valorization. In particular, the whole process was divided in two main parts. A first pretreatment with hot water in an autoclave allowed the separation of a solution containing the soluble proteins and sugars, which accounted for 25% of the total starting biomass. This first step allowed the preparation of a medium that was successfully employed as a valuable growing medium for different microbial fermentations, leading to valuable fungal biomass as well as triglycerides with a high content of linear or branched fatty acids, depending on the microorganism used. The solid water-insoluble residue was then submitted to a lignocellulose deep eutectic solvent-mediated fractionation, which allowed the recovery of two important main fractions: BSG cellulose and BSG lignin. The latter product was tested as potential precursor for the development of cement water reducers with encouraging results. This combination of treatments of the waste biomass appeared to be a promising sustainable strategy for the development of the full exploitation of BSG from a circular economy perspective. Full article

(This article belongs to the Special Issue Resource Recovery of Wastes by Fermentation towards a Sustainable Circular Economy)

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22 pages, 22962 KB

Open AccessEditor’s ChoiceArticle

Applying AI Tools for Modeling, Predicting and Managing the White Wine Fermentation Process

by Adrian Florea, Anca Sipos and Melisa-Cristina Stoisor

Fermentation 2022, 8(4), 137; https://doi.org/10.3390/fermentation8040137 - 22 Mar 2022

Cited by 17 | Viewed by 6989

Abstract

This paper reveals two of the challenges faced by Romania and proposes a sustainable and simple solution for its wine industry. First, substantial areas with vineyards that may produce qualitative wine, and second, the very low digitalization rate of industrial sectors. More precisely, [...] Read more.

This paper reveals two of the challenges faced by Romania and proposes a sustainable and simple solution for its wine industry. First, substantial areas with vineyards that may produce qualitative wine, and second, the very low digitalization rate of industrial sectors. More precisely, this work proposes a solution for digitalizing the fermentation process of white wine, allowing it to be adapted for other control techniques (i.e., knowledge-based systems, intelligent control). Our method consists of implementing a pre-trained multi-layer perceptron neural network, using genetic algorithms capable of predicting the concentration of alcohol and the amount of substrate at a certain point in time that starts from the initial configuration of the fermentation process. The purpose of predicting these process features is to obtain information about status variables so that the process can be automatically driven. The main advantage of our application is to help experts reduce the time needed for making the relevant measurements and to increase the lifecycles of sensors in bioreactors. After comprehensive simulations using experimental data obtained from previous fermentation processes, we concluded that a configuration that is close to the optimal one, for which the prediction accuracy is high, is a neural network (NN) having an input layer with neurons for temperature, time, initial substrate concentration, and the biomass concentration, a hidden layer with 10 neurons, and an output layer with 2 neurons representing the alcohol and substrate concentration, respectively. The best results were obtained with a pre-trained NN, using a genetic algorithm (GA) with a population of 50 individuals for 20 generations, a crossover probability of 0.9, and a probability of mutation of 0.5 that uniformly decreases depending on the generations, based on a beta coefficient of 0.3 and an elitist selection method. In the case of a data set with a larger number of variables, which also contains data regarding pH and CO₂, the prediction accuracy is even higher, leading to the conclusion that a larger data set positively influences the performance of the neural network. Furthermore, methods based on artificial intelligence applications like neural networks, along with various heuristic optimization methods such as genetic algorithms, are essential if hardware sensors cannot be used, or if direct measurements cannot be made. Full article

(This article belongs to the Special Issue Machine Learning in Fermented Food and Beverages)

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20 pages, 1876 KB

Open AccessEditor’s ChoiceArticle

Sustainable and Eco-Friendly Conversions of Olive Mill Wastewater-Based Media by Pleurotus pulmonarius Cultures

by Ilias Diamantis, Eirini-Maria Melanouri, Marianna Dedousi, Ioanna Panagopoulou, Seraphim Papanikolaou, Nikolaos G. Stoforos and Panagiota Diamantopoulou

Fermentation 2022, 8(3), 129; https://doi.org/10.3390/fermentation8030129 - 16 Mar 2022

Cited by 21 | Viewed by 4235

Abstract

Pleurotus pulmonarius mushroom was cultivated on liquid cultures with olive mill wastewaters (OMWs) of initial phenolic compound concentrations of 0 (control), 1, 2 and 3 g/L and glucose at initial concentrations of 40 and 60 g/L. The ability of the fungus to grow [...] Read more.

Pleurotus pulmonarius mushroom was cultivated on liquid cultures with olive mill wastewaters (OMWs) of initial phenolic compound concentrations of 0 (control), 1, 2 and 3 g/L and glucose at initial concentrations of 40 and 60 g/L. The ability of the fungus to grow on media containing toxic compounds enriched with glucose was assessed through biomass production, glucose consumption, polysaccharide (IPS) accumulation and total cellular lipids biosynthesis, while the total phenolic compounds (TPC) and antioxidant component monitoring were also assessed during a 43-day fermentation. An analysis of the total simple sugar composition of IPS and the total fatty acid composition of lipids was performed. The phenolic reduction and media decolorization were also monitored. Results showed that the addition of glucose in OMW-based media had a positive effect on biomass, IPS and lipid production and increased the unsaturated fatty acids and TPC concentration. The maximum recorded values were the following: biomass 32.76 g/L, IPS 4.38 g/L (14.70%, w/w in dry weight), lipids 2.85 g/L (11.69%, w/w in dry weight). The mycelial lipids were unsaturated and dominated by linoleic acid, whereas IPS were composed mainly of glucose. Significant phenolic compound reduction (87–95%) and color removal (70–85%) occurred. Results strongly suggest the potentiality of P. pulmonarius utilization in the OMW treatment. Full article

(This article belongs to the Special Issue Organic Waste Valorization into Added-Value Products)

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11 pages, 912 KB

Open AccessEditor’s ChoiceArticle

Single Cell Protein Production through Multi Food-Waste Substrate Fermentation

by Alessia Tropea, Antonio Ferracane, Ambrogina Albergamo, Angela Giorgia Potortì, Vincenzo Lo Turco and Giuseppa Di Bella

Fermentation 2022, 8(3), 91; https://doi.org/10.3390/fermentation8030091 - 23 Feb 2022

Cited by 60 | Viewed by 15292

Abstract

Today, food valorization represents an important challenge to environmental sustainability. Food waste can be used as a substrate for single cell protein production suitable for animal feed. In this study, animal and agricultural food waste, represented by fish, pineapple, banana, apple, and citrus [...] Read more.

Today, food valorization represents an important challenge to environmental sustainability. Food waste can be used as a substrate for single cell protein production suitable for animal feed. In this study, animal and agricultural food waste, represented by fish, pineapple, banana, apple, and citrus peels, have been used simultaneously as a fermentation substrate for single cell protein production by Saccharomyces cerevisiae, to evaluate the possibility of using a multi complex substrate for a simultaneous biovalorization of different food waste. The fermentation process was implemented by the supplementation of a hydrolytic enzyme and nutrient to allow the best yeast growing conditions. At the end of the process, the final substrate was enriched in protein, reaching up to 40.19% of protein, making the multisubstrate useful for animal feed. The substrate was also investigated for crude lipid, ash, lignin, soluble and insoluble sugar. The substrate composition at the end of the fermentation process was represented by 14.46% of crude lipid, 1.08% ash, 6.29% lignin. Conversely, the soluble and insoluble sugars dropped down from 20.5% to 6.10% and 19.15% to 2.14%, respectively, at the end of the process. Full article

(This article belongs to the Collection Food Waste Valorization)

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10 pages, 4511 KB

Open AccessEditor’s ChoiceArticle

Effects of Mulberry Branch and Leaves Silage on Microbial Community, Rumen Fermentation Characteristics, and Milk Yield in Lactating Dairy Cows

by Yan Li, Jiaqi Wang, Jie Mei, Lingxia Huang and Hongyun Liu

Fermentation 2022, 8(2), 86; https://doi.org/10.3390/fermentation8020086 - 18 Feb 2022

Cited by 19 | Viewed by 4469

Abstract

This study investigated the effects of mulberry branch and leaves (MBL) silage on milk yield, ruminal fermentation, and bacteria composition in dairy cows. Thirty-six mid-lactation cows were selected and randomly allocated into three groups. The control group (C) was fed on a total [...] Read more.

This study investigated the effects of mulberry branch and leaves (MBL) silage on milk yield, ruminal fermentation, and bacteria composition in dairy cows. Thirty-six mid-lactation cows were selected and randomly allocated into three groups. The control group (C) was fed on a total mixed ratio (TMR) diet, while the experimental groups were fed on TMR supplemented with 5% (L) and 10% (H) MBL silage. The experiment lasted for eight weeks, including two weeks of adaption. The results showed that Group H had an increased milk yield, milk fat content (p < 0.05), and 4% feed conversion ratio (p = 0.10). In addition, rumen propionic acid was significantly increased (p < 0.05), while acetate/propionate was significantly decreased (p < 0.05) in the high MBL silage group. The microbiome analysis showed that Bacteroides, Firmicutes, and Proteobacteria were the predominant phyla. Compared with Group C, the abundance of Bacteroides was significantly decreased (p < 0.01), while the Firmicutes and Proteobacteria were increased but not significantly different in Groups L and H. Prevotella was significantly decreased (p < 0.05) in the MBL silage groups, and Succinivibrionaceae_UCG-001 was increased in Group H. The correlation analysis showed that eight bacterial species belonging to Firmicutes were positively correlated with propionic acid. However, four bacterial species belonging to the Bacteroides group were negatively correlated with propionic acid. In conclusion, feed supplementation with about 5–10% of MBL silage could modulate the rumen microbiota and fermentation, and increase the abundance of fiber-digesting, propionic acid synthesis and milk fat-related microorganisms, thus improving milk yield in dairy cows. Full article

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

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18 pages, 4605 KB

Open AccessEditor’s ChoiceArticle

Production of Fumaric Acid by Rhizopus arrhizus NRRL 1526: A Simple Production Medium and the Kinetic Modelling of the Bioprocess

by Victor Martin-Dominguez, Paula I. Aleman Cabrera, Laslo Eidt, Ulf Pruesse, Anja Kuenz, Miguel Ladero and Victoria E. Santos

Fermentation 2022, 8(2), 64; https://doi.org/10.3390/fermentation8020064 - 30 Jan 2022

Cited by 9 | Viewed by 7714

Abstract

Fumaric acid is a promising monomer to obtain biomass-based polyesters and polyamides, and it is mainly produced by fungi of the Rhizopus genus in medium to high titters. The use of glucose, a main component of starchy and cellulosic food waste, as carbon [...] Read more.

Fumaric acid is a promising monomer to obtain biomass-based polyesters and polyamides, and it is mainly produced by fungi of the Rhizopus genus in medium to high titters. The use of glucose, a main component of starchy and cellulosic food waste, as carbon source, together with a low-nitrogen source concentration, is a promising route to reduce process costs. In this work, the effects of nitrogen and carbonate sources on Rhizopus arrhizus NRRL 1526 morphology and fumaric acid productivity were analysed, simplifying the traditional production broth composition. Moreover, a non-structured, non-segregated kinetic model was proposed and fitted to concentration data of all relevant components obtained in batches performed in triplicate with the selected production broth at 34 °C and 200 rpm in an orbital shaker. Full article

(This article belongs to the Special Issue Fermentative Production of Biofuels and Bioproducts within a Biorefinery Perspective)

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14 pages, 3196 KB

Open AccessEditor’s ChoiceArticle

Effect of Lactobacillus plantarum Inoculation on Chemical Composition, Fermentation, and Bacterial Community Composition of Ensiled Sweet Corn Whole Plant or Stover

by Zhi-Yuan Ma, Emilio Ungerfeld, Zhu Ouyang, Xiao-Ling Zhou, Xue-Feng Han, Yan-Qin Zeng and Zhi-Liang Tan

Fermentation 2022, 8(1), 24; https://doi.org/10.3390/fermentation8010024 - 10 Jan 2022

Cited by 7 | Viewed by 3957

Abstract

Sweet corn is a feed resource with a high content of water-soluble carbohydrates (WSC) available for ruminant production. This study was conducted to investigate the effect of inoculation with Lactobacillus plantarum on fermentation and nutritional quality of sweet corn silage. Sweet corn whole [...] Read more.

Sweet corn is a feed resource with a high content of water-soluble carbohydrates (WSC) available for ruminant production. This study was conducted to investigate the effect of inoculation with Lactobacillus plantarum on fermentation and nutritional quality of sweet corn silage. Sweet corn whole plant (WP) and sweet corn stover (CS) were ensiled in mini silos with or without inoculation of L. plantarum. Proximate composition and fermentation variables, and composition of the bacterial community, were evaluated before ensiling and at the end of the first, second, and third month after ensiling. There was fiber degradation in CS silage after three months of ensilage, but not in WP silage. Inoculation of WP silage, but not of CS silage, with L. plantarum, increased starch content. The relative abundance of genus Lactobacillus was increased by inoculation with L. plantarum by 14.2% and 82.2% in WP and CS silage, respectively. Inoculation with L. plantarum was not necessary to achieve adequate fermentation of either WP or CS silage, as the abundance of native lactic acid bacteria in both materials seemed suitable for adequate fermentation. That said, increased starch content in WP resulting from inoculation with L. plantarum can increase the nutritive value of WP for ruminants. Full article

(This article belongs to the Special Issue Silage Fermentation)

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13 pages, 2261 KB

Open AccessEditor’s ChoiceArticle

Supplemental Aspergillus Lipase and Protease Preparations Display Powerful Bifidogenic Effects and Modulate the Gut Microbiota Community of Rats

by Yongshou Yang, Thanutchaporn Kumrungsee, Norihisa Kato, Shinji Fukuda, Manabu Kuroda and Shotaro Yamaguchi

Fermentation 2021, 7(4), 294; https://doi.org/10.3390/fermentation7040294 - 1 Dec 2021

Cited by 12 | Viewed by 6466

Abstract

Aspergillus-derived protease and lipase, which are involved in the production of Aspergillus-fermented foods, are consumed as digestive enzyme supplements. A marked bifidogenic effect of supplemental Aspergillus protease preparation (AP) in rats fed with a high-fat diet was identified. This study was [...] Read more.

Aspergillus-derived protease and lipase, which are involved in the production of Aspergillus-fermented foods, are consumed as digestive enzyme supplements. A marked bifidogenic effect of supplemental Aspergillus protease preparation (AP) in rats fed with a high-fat diet was identified. This study was conducted to examine whether the consumption of Aspergillus-derived lipase exerts similar bifidogenic effect. Rats were fed diets supplemented with either an Aspergillus-derived lipase preparation (AL) or AP at 0.1% for two weeks. 16S rRNA gene sequencing analysis indicated that supplemental AL and AP markedly influenced cecal microbial community. At the phylum level, treatment with AL and AP resulted in a lower relative abundance of Firmicutes and Bacteroidetes, but a higher relative abundance of Actinobacteria and Proteobacteria than the control rats (p < 0.05). At the genus level, AL and AP remarkedly elevated the relative abundances of Bifidobacterium, Collinsella, and Enterococcus, but significantly reduced those of Oscillospira, Dorea, and Coprobacillus (p < 0.05). These modulations were similar to those reported by several studies with typical prebiotic oligosaccharides. Notably, the bifidogenic effect of AL was much greater than that of AP. Our results show that the two different Aspergillus-derived preparations, AL and AP, have strong bifidogenic effects and can change the microbiota’s composition. Full article

(This article belongs to the Special Issue Fermented Foods and Microbes Related to Health)

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21 pages, 1236 KB

Open AccessEditor’s ChoiceArticle

Wine Saccharomyces Yeasts for Beer Fermentation

by Vanesa Postigo, Margarita García, Juan Mariano Cabellos and Teresa Arroyo

Fermentation 2021, 7(4), 290; https://doi.org/10.3390/fermentation7040290 - 30 Nov 2021

Cited by 28 | Viewed by 9186

Abstract

Multiple studies in recent years have shown the potential of Saccharomyces wild yeasts to produce craft beers with new flavour profiles and other desirable properties. Yeasts isolated from food (wine, bread, kombucha…) have shown potential promise for application in brewing. The aim of [...] Read more.

Multiple studies in recent years have shown the potential of Saccharomyces wild yeasts to produce craft beers with new flavour profiles and other desirable properties. Yeasts isolated from food (wine, bread, kombucha…) have shown potential promise for application in brewing. The aim of this study is to evaluate the ability of 141 Saccharomyces yeast strains isolated from the Madrilenian agriculture (from grapes, must, wine, vineyard, and cellars) to produce a novel ale beer. Fermentation activity of the strains was compared against the commercial strain Saccharomyces cerevisiae Safale S-04. In addition to the other aspects such as melatonin production, thirty-three volatile compounds belonging to higher alcohols, esters, aldehydes/cetones, acids, lactones and phenolic groups, were analysed by GC for selection of the strains. Ten strains were finally chosen, among which the most relevant was the strain G 520 showing a higher production of esters, higher alcohols and acids compared with S-04. The apparent attenuation for this strain was lower than commercial strain, which translates into more residual sugars. Furthermore, G 520 was more capable of producing significantly higher amounts of melatonin studied by HPLC, as well as showing a higher antioxidant capacity. Consumer study showed that G 520 strain could be used to produce a potential beer that has a place in the current market. Full article

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

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15 pages, 1113 KB

Open AccessEditor’s ChoiceArticle

Use of Lachancea thermotolerans for Biological vs. Chemical Acidification at Pilot-Scale in White Wines from Warm Areas

by Cristian Vaquero, Pedro Miguel Izquierdo-Cañas, Adela Mena-Morales, L. Marchante-Cuevas, José María Heras and Antonio Morata

Fermentation 2021, 7(3), 193; https://doi.org/10.3390/fermentation7030193 - 15 Sep 2021

Cited by 26 | Viewed by 4734

Abstract

Climate change is affecting vineyards, resulting in grapes with a low acidity a high pH and sugar at harvest time. The most common procedure so far to improve the acidity and reduce the final pH of wines is to use tartaric acid, but [...] Read more.

Climate change is affecting vineyards, resulting in grapes with a low acidity a high pH and sugar at harvest time. The most common procedure so far to improve the acidity and reduce the final pH of wines is to use tartaric acid, but wine can also be acidified microbiologically using Lachancea thermotolerans yeasts, a natural bio-tool that acidifies gradually during the first stage/days of fermentation. Two strains of L. thermotolerans were compared with one Saccharomyces cerevisiae at a pilot-scale under similar fermentation conditions and in duplicate. A sequential inoculation was performed on the third day for the non-Saccharomyces, producing only about 1 g/L of lactic acid, which was suitable for comparison with the Saccharomyces, to which 1.5 g/L of tartaric acid had been added to lower the final pH. The three fermentations ended with a total acidity without significant differences. A significant and normal feature of the L. thermotolerans yeasts is their higher propane-1,2,3-triol production, which was observed in the Laktia yeast, and the acetic acid was <0.3 g/L. The amount of volatile metabolites was generally higher for non-Saccharomyces and the increase was seen in carbonyl compounds, organic acids, lactones, fumaric compounds, and phenols. Finally, the sensory analysis showed that there were hardly any significant differences, even though the non-Saccharomyces had a higher quantity of volatile metabolites, which could lead to a good acceptance of the product, since biological acidification was used, generating a more natural product. Full article

(This article belongs to the Special Issue Enological Repercussions of Non-Saccharomyces Species 3.0)

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20 pages, 7495 KB

Open AccessEditor’s ChoiceArticle

Mixed-Culture Metagenomics of the Microbes Making Sour Beer

by Renan Eugênio Araujo Piraine, Fábio Pereira Leivas Leite and Matthew L. Bochman

Fermentation 2021, 7(3), 174; https://doi.org/10.3390/fermentation7030174 - 30 Aug 2021

Cited by 15 | Viewed by 6487

Abstract

Mixed microbial cultures create sour beers but many brewers do not know which microbes comprise their cultures. The objective of this work was to use deep sequencing to identify microorganisms in sour beers brewed by spontaneous and non-spontaneous methods. Twenty samples were received [...] Read more.

Mixed microbial cultures create sour beers but many brewers do not know which microbes comprise their cultures. The objective of this work was to use deep sequencing to identify microorganisms in sour beers brewed by spontaneous and non-spontaneous methods. Twenty samples were received from brewers, which were processed for microbiome analysis by next generation sequencing. For bacteria, primers were used to amplify the V3-V4 region of the 16S rRNA gene; fungal DNA detection was performed using primers to amplify the entire internal transcribed spacer region. The sequencing results were then used for taxonomy assignment, sample composition, and diversity analyses, as well as nucleotide BLAST searching. We identified 60 genera and 140 species of bacteria, of which the most prevalent were Lactobacillus acetotolerans, Pediococcus damnosus, and Ralstonia picketti/mannitolilytica. In fungal identification, 19 genera and 26 species were found, among which the most common yeasts were Brettanomyces bruxellensis and Saccharomyces cerevisiae. In some cases, genetic material from more than 60 microorganisms was found in a single sample. In conclusion, we were able to determine the microbiomes of various mixed cultures used to produce beer, providing useful information to better understand the sour beer fermentation process and brewing techniques. Full article

(This article belongs to the Special Issue Mixed Culture Fermentation)

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14 pages, 1804 KB

Open AccessEditor’s ChoiceArticle

Digital Smoke Taint Detection in Pinot Grigio Wines Using an E-Nose and Machine Learning Algorithms Following Treatment with Activated Carbon and a Cleaving Enzyme

by Vasiliki Summerson, Claudia Gonzalez Viejo, Damir D. Torrico, Alexis Pang and Sigfredo Fuentes

Fermentation 2021, 7(3), 119; https://doi.org/10.3390/fermentation7030119 - 16 Jul 2021

Cited by 19 | Viewed by 4285

Abstract

The incidence and intensity of bushfires is increasing due to climate change, resulting in a greater risk of smoke taint development in wine. In this study, smoke-tainted and non-smoke-tainted wines were subjected to treatments using activated carbon with/without the addition of a cleaving [...] Read more.

The incidence and intensity of bushfires is increasing due to climate change, resulting in a greater risk of smoke taint development in wine. In this study, smoke-tainted and non-smoke-tainted wines were subjected to treatments using activated carbon with/without the addition of a cleaving enzyme treatment to hydrolyze glycoconjugates. Chemical measurements and volatile aroma compounds were assessed for each treatment, with the two smoke taint amelioration treatments exhibiting lower mean values for volatile aroma compounds exhibiting positive ‘fruit’ aromas. Furthermore, a low-cost electronic nose (e-nose) was used to assess the wines. A machine learning model based on artificial neural networks (ANN) was developed using the e-nose outputs from the unsmoked control wine, unsmoked wine with activated carbon treatment, unsmoked wine with a cleaving enzyme plus activated carbon treatment, and smoke-tainted control wine samples as inputs to classify the wines according to the smoke taint amelioration treatment. The model displayed a high overall accuracy of 98% in classifying the e-nose readings, illustrating it may be a rapid, cost-effective tool for winemakers to assess the effectiveness of smoke taint amelioration treatment by activated carbon with/without the use of a cleaving enzyme. Furthermore, the use of a cleaving enzyme coupled with activated carbon was found to be effective in ameliorating smoke taint in wine and may help delay the resurgence of smoke aromas in wine following the aging and hydrolysis of glycoconjugates. Full article

(This article belongs to the Special Issue Implementation of Digital Technologies on Beverage Fermentation)

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18 pages, 4078 KB

Open AccessEditor’s ChoiceArticle

Smart Detection of Faults in Beers Using Near-Infrared Spectroscopy, a Low-Cost Electronic Nose and Artificial Intelligence

by Claudia Gonzalez Viejo, Sigfredo Fuentes and Carmen Hernandez-Brenes

Fermentation 2021, 7(3), 117; https://doi.org/10.3390/fermentation7030117 - 15 Jul 2021

Cited by 32 | Viewed by 6226

Abstract

Early detection of beer faults is an important assessment in the brewing process to secure a high-quality product and consumer acceptability. This study proposed an integrated AI system for smart detection of beer faults based on the comparison of near-infrared spectroscopy (NIR) and [...] Read more.

Early detection of beer faults is an important assessment in the brewing process to secure a high-quality product and consumer acceptability. This study proposed an integrated AI system for smart detection of beer faults based on the comparison of near-infrared spectroscopy (NIR) and a newly developed electronic nose (e-nose) using machine learning modelling. For these purposes, a commercial larger beer was used as a base prototype, which was spiked with 18 common beer faults plus the control aroma. The 19 aroma profiles were used as targets for classification ma-chine learning (ML) modelling. Six different ML models were developed; Model 1 (M1) and M2 were developed using the NIR absorbance values (100 inputs from 1596–2396 nm) and e-nose (nine sensor readings) as inputs, respectively, to classify the samples into control, low and high concentration of faults. Model 3 (M3) and M4 were based on NIR and M5 and M6 based on the e-nose readings as inputs with 19 aroma profiles as targets for all models. A customized code tested 17 artificial neural network (ANN) algorithms automatically testing performance and neu-ron trimming. Results showed that the Bayesian regularization algorithm was the most adequate for classification rendering precisions of M1 = 95.6%, M2 = 95.3%, M3 = 98.9%, M4 = 98.3%, M5 = 96.8%, and M6 = 96.2% without statistical signs of under- or overfitting. The proposed system can be added to robotic pourers and the brewing process at low cost, which can benefit craft and larger brewing companies. Full article

(This article belongs to the Special Issue Implementation of Digital Technologies on Beverage Fermentation)

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19 pages, 746 KB

Open AccessEditor’s ChoiceArticle

Bacteriocinogenic Bacillus spp. Isolated from Korean Fermented Cabbage (Kimchi)—Beneficial or Hazardous?

by Joanna Ivy Irorita Fugaban, Jorge Enrique Vazquez Bucheli, Wilhelm Heinrich Holzapfel and Svetoslav Dimitrov Todorov

Fermentation 2021, 7(2), 56; https://doi.org/10.3390/fermentation7020056 - 7 Apr 2021

Cited by 16 | Viewed by 5189

Abstract

Bacillus velezensis ST03 and ST32, Bacillus amyloliquefaciens ST06 and ST109, and Bacillus subtilis ST08 were isolated from artisanal-produced kimchi and were identified based on 16S rRNA partial sequencing. DNA obtained from the investigated bacilli generated positive results for lichenicidin, iturin, subtilosin, and surfactin [...] Read more.

Bacillus velezensis ST03 and ST32, Bacillus amyloliquefaciens ST06 and ST109, and Bacillus subtilis ST08 were isolated from artisanal-produced kimchi and were identified based on 16S rRNA partial sequencing. DNA obtained from the investigated bacilli generated positive results for lichenicidin, iturin, subtilosin, and surfactin on a strain-specific basis. The strains were found to produce antimicrobial metabolites with activity levels ranging between 800 and 1600 AU/mL on a strain-specific basis, as determined against Listeria monocytogenes ATCC15313. Moreover, all tested strains in this study were still active after treatment with proteolytic enzymes, even with reduced inhibition zones compared to the controls, pointing to additional antimicrobial activity possibly related to a non-proteinaceous molecular structure. Most probably these strains may express surfactin as an additional factor in their complex antimicrobial activity. B. amyloliquefaciens ST09 and B. velezensis ST03 and ST32 were characterized as positive for β-hemolysis. B. subtilis ST08 was shown to be positive for hblC and nheC and B. amyloliquefaciens ST109 for nheB. B. amyloliquefaciens ST109 generated positive results for gelatinase activity. The ability of the studied Bacillus strains to metabolize different carbohydrate sources was done based on the API50CHB test, while the enzyme production profile was recorded by the APIZym kit. All studied strains were positive producers for biogenic amines production. Studied Bacillus spp. strains were resistant to some of the evaluated antibiotics, tested according to recommendations of CLSI and EFSA. Full article

(This article belongs to the Special Issue Fermented Foods and Microbes Related to Health)

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17 pages, 767 KB

Open AccessEditor’s ChoiceReview

Biodiversity of Oenological Lactic Acid Bacteria: Species- and Strain-Dependent Plus/Minus Effects on Wine Quality and Safety

by Vittorio Capozzi, Maria Tufariello, Nicola De Simone, Mariagiovanna Fragasso and Francesco Grieco

Fermentation 2021, 7(1), 24; https://doi.org/10.3390/fermentation7010024 - 17 Feb 2021

Cited by 52 | Viewed by 8832

Abstract

Winemaking depends on several elaborate biochemical processes that see as protagonist either yeasts or lactic acid bacteria (LAB) of oenological interest. In particular, LAB have a fundamental role in determining the quality chemical and aromatic properties of wine. They are essential not only [...] Read more.

Winemaking depends on several elaborate biochemical processes that see as protagonist either yeasts or lactic acid bacteria (LAB) of oenological interest. In particular, LAB have a fundamental role in determining the quality chemical and aromatic properties of wine. They are essential not only for malic acid conversion, but also for producing several desired by-products due to their important enzymatic activities that can release volatile aromatic compounds during malolactic fermentation (e.g., esters, carbonyl compounds, thiols, monoterpenes). In addition, LAB in oenology can act as bioprotectors and reduce the content of undesired compounds. On the other hand, LAB can affect wine consumers’ health, as they can produce harmful compounds such as biogenic amines and ethyl carbamate under certain conditions during fermentation. Several of these positive and negative properties are species- and strain-dependent characteristics. This review focuses on these aspects, summarising the current state of knowledge on LAB’s oenological diversity, and highlighting their influence on the final product’s quality and safety. All our reported information is of high interest in searching new candidate strains to design starter cultures, microbial resources for traditional/typical products, and green solutions in winemaking. Due to the continuous interest in LAB as oenological bioresources, we also underline the importance of inoculation timing. The considerable variability among LAB species/strains associated with spontaneous consortia and the continuous advances in the characterisation of new species/strains of interest for applications in the wine sector suggest that the exploitation of biodiversity belonging to this heterogeneous group of bacteria is still rising. Full article

(This article belongs to the Special Issue Lactic Acid Fermentation and the Colours of Biotechnology 2.0)

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11 pages, 1739 KB

Open AccessEditor’s ChoiceArticle

Predicting Fermentation Rates in Ale, Lager and Whisky

by Struan J. Reid, Maria Josey, Andrew J. MacIntosh, Dawn L. Maskell and R. Alex Speers

Fermentation 2021, 7(1), 13; https://doi.org/10.3390/fermentation7010013 - 14 Jan 2021

Cited by 9 | Viewed by 6681

Abstract

Recently there has been an increased interest in characterising the rates of alcoholic fermentations. Sigmoidal models have been used to predict changes such as the rate of density decline. In this study, three published sigmoidal models were assessed and fit to industrial fermentation [...] Read more.

Recently there has been an increased interest in characterising the rates of alcoholic fermentations. Sigmoidal models have been used to predict changes such as the rate of density decline. In this study, three published sigmoidal models were assessed and fit to industrial fermentation data. The first is the four-parameter logistic model described in the ASBC Yeast-14 method. The second model is a nested form of the four-parameter logistic function, adding an extra parameter, creating the 5-parameter logistic equation., where an additional parameter was added to allow for asymmetry. The final model is a three-parameter logistic equation which describes the change in the Apparent Degree of Fermentation with time. The three models were compared by fitting them to industrial data from Australian and Canadian lagers, American and Scottish ales and Scotch Whisky fermentations. The model fits were then compared to one another with a technique developed by Akaike and a nested F-test. The Akaike information criterion compares the models and accounts for both the goodness of fit, and the number of parameters in the model. Finally, consideration was given to the establishment of prediction bands (that enclose the area that one can be 99% sure contains the true datapoints). Calculation of these bands was “challenging” but successful as the industrial fermentation data was heteroscedastic. Full article

(This article belongs to the Special Issue Brewing & Distilling 2.0)

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15 pages, 4452 KB

Open AccessEditor’s ChoiceReview

An Overview of CRISPR-Based Technologies in Wine Yeasts to Improve Wine Flavor and Safety

by Alice Vilela

Fermentation 2021, 7(1), 5; https://doi.org/10.3390/fermentation7010005 - 2 Jan 2021

Cited by 29 | Viewed by 11771

Abstract

Modern industrial winemaking is based on the use of specific starters of wine strains. Commercial wine strains present several advantages over natural isolates, and it is their use that guarantees the stability and reproducibility of industrial winemaking technologies. For the highly competitive wine [...] Read more.

Modern industrial winemaking is based on the use of specific starters of wine strains. Commercial wine strains present several advantages over natural isolates, and it is their use that guarantees the stability and reproducibility of industrial winemaking technologies. For the highly competitive wine market with new demands for improved wine quality and wine safety, it has become increasingly critical to develop new yeast strains. In the last decades, new possibilities arose for creating upgraded wine yeasts in the laboratory, resulting in the development of strains with better fermentation abilities, able to improve the sensory quality of wines and produce wines targeted to specific consumers, considering their health and nutrition requirements. However, only two genetically modified (GM) wine yeast strains are officially registered and approved for commercial use. Compared with traditional genetic engineering methods, CRISPR/Cas9 is described as efficient, versatile, cheap, easy-to-use, and able to target multiple sites. This genetic engineering technique has been applied to Saccharomyces cerevisiae since 2013. In this review, we aimed to overview the use of CRISPR/Cas9 editing technique in wine yeasts to combine develop phenotypes able to increase flavor compounds in wine without the development of off-flavors and aiding in the creation of “safer wines.” Full article

(This article belongs to the Special Issue Yeast Biotechnology 4.0)

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