Fermentation

14 pages, 1629 KB

Open AccessArticle

Screening and Application of Pseudomonas protegens from Municipal Sludge for the Degradation of 2,2′,4,4′-Tetrabromodiphenyl Ether (BDE-47) in Contaminated Soil and Water

by Yanting Wu, Yuanping Li, Tianyun Zhou, Yaoning Chen, Li Zhu, Guowen He, Nianping Chi, Shunyao Jia, Wenqiang Luo and Ganquan Zhang

Fermentation 2025, 11(9), 547; https://doi.org/10.3390/fermentation11090547 - 22 Sep 2025

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Abstract

2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47) is a refractory organic pollutant that is characterized by its persistence, toxicity and potential for bioaccumulation. As a typical biocontrol bacteria, Pseudomonas protegens has not been reported to degrade organic pollutants in the environment. A single strain of Pseudomonas protegens [...] Read more.

2,2′,4,4′-Tetrabromodiphenyl ether (BDE-47) is a refractory organic pollutant that is characterized by its persistence, toxicity and potential for bioaccumulation. As a typical biocontrol bacteria, Pseudomonas protegens has not been reported to degrade organic pollutants in the environment. A single strain of Pseudomonas protegens was isolated and acclimated from municipal sludge, and its ability to degrade BDE-47 was investigated. The enhancing effects of different carbon sources and inducers on Pseudomonas protegens were also examined. Through the reinforcement of bacterial enhancers, Pseudomonas protegens was applied to remediate soil and water contaminated with BDE-47. Based on colony characteristics, physiological and biochemical properties, and 16S rDNA gene sequence homology analysis, the strain was identified as Pseudomonas protegens and named YP1. This marks the first discovery of Pseudomonas protegens being capable of degrading BDE-47. Strain YP1 utilized BDE-47 as a carbon source and achieved a degradation rate of 69.57% after 75 h of incubation under conditions of 37 °C, pH 7, and constant temperature in a dark shaking incubator. After comparing the actual enhancement effects, glucose was selected as the carbon source and 2,4-dichlorophenol as the inducer to improve the environmental remediation capability of Pseudomonas protegens. After 14 days of remediation, the degradation rates of BDE-47 in contaminated soil and water reached 48.26% and 52.60%, respectively. The Pseudomonas protegens strain obtained from municipal sludge through screening, acclimation, and enhancement processes exhibits excellent environmental remediation capabilities and promising practical application prospects. Full article

(This article belongs to the Section Industrial Fermentation)

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17 pages, 2613 KB

Open AccessArticle

Analysis of Functional Component Alterations and Antioxidant Response Mechanisms in Microbial-Enzymatic Co-Fermentation-Induced Quinoa Bran

by Min Li, Qianfang Zhang and Jingyan Meng

Fermentation 2025, 11(9), 546; https://doi.org/10.3390/fermentation11090546 - 22 Sep 2025

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Abstract

This study utilised Bacillus subtilis and cellulase combined with Bacillus subtilis to ferment quinoa bran. The effects of different fermentation methods on the functional components, antioxidant activity, and structural changes of quinoa bran were evaluated. Fermentation altered the functional components of quinoa bran [...] Read more.

This study utilised Bacillus subtilis and cellulase combined with Bacillus subtilis to ferment quinoa bran. The effects of different fermentation methods on the functional components, antioxidant activity, and structural changes of quinoa bran were evaluated. Fermentation altered the functional components of quinoa bran and enhanced its antioxidant capacity. The phenolic acid and polysaccharide contents increased in BFQ (Bacillus subtilis-fermented quinoa bran) and BEFQ (bacterio-enzyme co-fermented quinoa bran), whereas the protein content decreased. After fermentation, the phenolic acid content in BEFQ increased by 81.68%, while the DPPH and ABTS radical-scavenging rates increased by 43.99% and 31.44%, respectively. The antioxidant capacity in BEFQ was ranked as follows: ferulic acid > p-coumaric acid > vanillic acid > 4-hydroxybenzoic acid. Thus, the antioxidant ability of quinoa bran phenolic acids was primarily dependent on hydroxycinnamic acid derivatives. The polysaccharide content in BEFQ increased by 80.73%. The DPPH and ABTS radical-scavenging rates increased by 52.59% and 50.48%, respectively, whereas the protein content decreased by 21.88%. Furthermore, the DPPH and ABTS radical-scavenging rates increased by 76% and 75.39%, respectively. These results indicate that fermentation using cellulase combined with Bacillus subtilis has the potential to enhance the antioxidant capacity and utilisation of quinoa bran. Full article

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22 pages, 4471 KB

Open AccessArticle

Continuous Fermentative Biohydrogen Production from Fruit-Vegetable Waste: A Parallel Approach to Assess Process Reproducibility

by Leonardo J. Martínez-Mendoza, Raúl Muñoz and Octavio García-Depraect

Fermentation 2025, 11(9), 545; https://doi.org/10.3390/fermentation11090545 - 19 Sep 2025

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Abstract

Dark fermentation (DF) has gained increasing interest over the past two decades as a sustainable route for biohydrogen production; however, understanding how reproducible the process can be, both from macro- and microbiological perspectives, remains limited. This study assessed the reproducibility of a parallel [...] Read more.

Dark fermentation (DF) has gained increasing interest over the past two decades as a sustainable route for biohydrogen production; however, understanding how reproducible the process can be, both from macro- and microbiological perspectives, remains limited. This study assessed the reproducibility of a parallel continuous DF system using fruit-vegetable waste as a substrate under strictly controlled operational conditions. Three stirred-tank reactors were operated in parallel for 90 days, monitoring key process performance indicators. In addition to baseline operation, different process enhancement strategies were tested, including bioaugmentation, supplementation with nutrients and/or additional fermentable carbohydrates, and modification of key operational parameters such as pH and hydraulic retention time, all widely used in the field to improve DF performance. Microbial community structure was also analyzed to evaluate its reproducibility and potential relationship with process performance and metabolic patterns. Under these conditions, key performance indicators and core microbial features were reproducible to a large extent, yet full consistency across reactors was not achieved. During operation, unforeseen operational issues such as feed line clogging, pH control failures, and mixing interruptions were encountered. Despite these disturbances, the system maintained an average hydrogen productivity of 3.2 NL H₂/L-d, with peak values exceeding 6 NL H₂/L-d under optimal conditions. The dominant microbial core included Bacteroides, Lactobacillus, Veillonella, Enterococcus, Eubacterium, and Clostridium, though their relative abundances varied notably over time and between reactors. An inverse correlation was observed between lactate concentration in the fermentation broth and the amount of hydrogen produced, suggesting it can serve as a precursor for hydrogen. Overall, the findings presented here demonstrate that DF processes can be resilient and broadly reproducible. However, they also emphasize the sensitivity of these processes to operational disturbances and microbial shifts. This underscores the necessity for refined control strategies and further systematic research to translate these insights into stable, high-performance real-world systems. Full article

(This article belongs to the Special Issue 10th Anniversary of Fermentation: Feature Papers in Section "Industrial Fermentation")

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15 pages, 1838 KB

Open AccessArticle

Evaluation of the Addition of Polyethylene Glycol in the Enzymatic Hydrolysis of Rice Husk

by Humberto Ayala Armijos and María C. Veiga

Fermentation 2025, 11(9), 544; https://doi.org/10.3390/fermentation11090544 - 19 Sep 2025

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Abstract

This study evaluated the effect of polyethylene glycol (PEG 1500 and 4000) addition on the enzymatic hydrolysis (EH) of ground rice husk (≤250 μm). To reduce the amount of enzyme adsorbed on silicon dioxide and lignin and to evaluate the enzymatic hydrolysis, PEG [...] Read more.

This study evaluated the effect of polyethylene glycol (PEG 1500 and 4000) addition on the enzymatic hydrolysis (EH) of ground rice husk (≤250 μm). To reduce the amount of enzyme adsorbed on silicon dioxide and lignin and to evaluate the enzymatic hydrolysis, PEG 1500 and 4000 g/mol were added at three concentrations (0.3, 0.4 and 0.5 g PEG/g SiO₂). When PEG 1500 was added at 0.5 g/g SiO₂, the conversion of cellulose to cellobiose was not significantly increased (p ≥ 0.05); the conversion to glucose was 41.76%, and the conversion of hemicellulose to xylose was 93.45%, all with respect to the control assay. Addition of PEG 4000 at 0.5 g/g SiO₂ showed an increase of 14.78% in the hydrolysis of cellulose to cellobiose, 56.59% in that of cellulose to glucose, and 93.24% in that of hemicellulose to xylose. The addition of PEG shows that at a higher molecular weight and higher concentration, there are significant differences in the percentage of conversion of cellulose and hemicellulose into fermentable sugars, achieving efficiencies of ≈75%. Full article

(This article belongs to the Special Issue Technological Advances in Lignocellulosic Biomass Conversion to Bioenergy)

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21 pages, 1407 KB

Open AccessArticle

Gas Endeavour Device for the Real-Time In Vitro Measurement of Carbon Dioxide and Methane Emissions Associated with Sheep Diets with Prickly Pear By-Products

by Riccardo Gannuscio, Giuseppe Maniaci and Massimo Todaro

Fermentation 2025, 11(9), 543; https://doi.org/10.3390/fermentation11090543 - 18 Sep 2025

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Abstract

Prickly pear by-products contain dietary fibre and bioactive components like polyphenols and flavonols, which can reduce total gas and methane emissions. To this end, an in vitro trial was carried out in duplicate utilizing three diets containing hay, concentrate, and two prickly pear [...] Read more.

Prickly pear by-products contain dietary fibre and bioactive components like polyphenols and flavonols, which can reduce total gas and methane emissions. To this end, an in vitro trial was carried out in duplicate utilizing three diets containing hay, concentrate, and two prickly pear by-products obtained after grinding the fruit peel and pastazzo (pulp + peel + seeds), which were ensiled with the addition of 12% wheat bran (raw weight). Based on the ingredient intake recorded in the in vivo study for 12 lactating ewes fed the three diets, an in vitro rumen fermentation study with the innovative Gas Endeavour system (GES) was performed, and the Gage R&R statistical method was used to evaluate the accuracy of the total gas and methane production detected by the GES device. Fermented liquor samples for each diet were used to calculate the disappearance of organic matter and neutral detergent fibre. Shotgun metagenome sequencing analysis was used to evaluate the effect of diet on the rumen fluid microbiota, and it was found that the parameters of repeatability and reproducibility of the total gas and the methane produced after 24 h were satisfactory. Prickly pear by-products display high fermentability for the peel and low fermentability for pastazzo silage, which generates lower total gas and methane emissions. This diminished methane gas production is not correlated with the relative abundance of methanogens. The different chemical and nutritional composition of the three diets altered the rumen bacteria, albeit only slightly, with particular reference to the Succinivibrio and Selenomonas genera. In conclusion, prickly pear peel silage displayed acceptable fermentation traits, which could support its utilization in sheep diets. Full article

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40 pages, 4383 KB

Open AccessArticle

Chitosan-Based Edible Films as Innovative Preservation Tools for Fermented and Dairy Products

by Fadime Seyrekoğlu and Esra Efdal

Fermentation 2025, 11(9), 542; https://doi.org/10.3390/fermentation11090542 - 18 Sep 2025

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Abstract

Extending the shelf life and ensuring microbial stability of processed foods are key objectives in the food industry. In this study, edible films containing chitosan, chitosan + thyme (Thymus vulgaris) oil, and chitosan + rosemary (Rosmarinus officinalis) oil were [...] Read more.

Extending the shelf life and ensuring microbial stability of processed foods are key objectives in the food industry. In this study, edible films containing chitosan, chitosan + thyme (Thymus vulgaris) oil, and chitosan + rosemary (Rosmarinus officinalis) oil were applied to traditional and industrial Cecil cheese using the dipping method, with control groups for each production type. Samples were stored at 4 ± 1 °C for 45 days, and physical (color, water activity, and texture), chemical (pH, acidity, and dry matter), microbiological (total aerobic mesophilic bacteria, yeast-mold, coliforms, and lactic acid bacteria), and sensory analyses were performed on days 1, 15, 30, and 45. Results indicated that chitosan-based films effectively limited microbial growth, with the chitosan + rosemary oil combination being particularly effective in reducing microbial load and maintaining textural stability. Traditional cheeses achieved higher overall acceptability, while purchase intent was greater for industrial products. Coated samples exhibited slower pH decline and more stable dry matter content; industrial cheeses retained moisture more effectively. Texture profile analysis showed more stable chewiness and springiness values in coated samples. In conclusion, natural edible films represent an effective approach for extending shelf life and preserving quality, particularly in traditional cheeses with fibrous structures and shorter shelf lives. Full article

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

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16 pages, 2215 KB

Open AccessArticle

Use of Lachancea thermotolerans and Metschnikowia pulcherrima to Improve Acidity and Sensory Profile of Verdejo Wines from Different Vine Management Systems

by María Soler, Juan Manuel Del Fresno, María Antonia Bañuelos, Antonio Morata and Iris Loira

Fermentation 2025, 11(9), 541; https://doi.org/10.3390/fermentation11090541 - 18 Sep 2025

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Abstract

A proper understanding of viticultural and oenological strategies is essential to adapt to climate change and consumer demands. The objective of this study was to evaluate the impact of different viticultural treatments and yeast strains on the chemical composition and sensory perception of [...] Read more.

A proper understanding of viticultural and oenological strategies is essential to adapt to climate change and consumer demands. The objective of this study was to evaluate the impact of different viticultural treatments and yeast strains on the chemical composition and sensory perception of wine. Two Verdejo musts, a control must (Must O) and one obtained with innovative viticultural strategies (Must E), were fermented with Saccharomyces cerevisiae, Lachancea thermotolerans, and a co-incubation of Lachancea thermotolerans with Metschnikowia pulcherrima. Fermentations with L. thermotolerans increased lactic acid content, reducing pH (a decrease of 0.2 points compared to controls) and having a positive impact on the perception of freshness. Wines fermented from Must E showed better colour parameters and a higher production of fermentative volatile compounds, but higher ethanol content and lower acidity. In contrast, wines fermented from Must O exhibited a more balanced aromatic profile, with fewer carbonyl compounds and higher alcohols (a 30% reduction in carbonyl compounds in wines fermented with non-Saccharomyces), which made them more harmonious in the sensory evaluations. The results highlight the importance of a good selection of viticultural and oenological strategies to achieve a desirable sensory profile under changing climatic conditions, highlighting the positive impact of non-Saccharomyces yeasts in improving acidity and aromatic profile. Full article

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

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15 pages, 1506 KB

Open AccessArticle

Productivity, Fermentation Parameters, and Chemical Composition of Silages from Biomass Sorghum Hybrids in Ratoon Crop

by Yara América da Silva, Marco Antonio Previdelli Orrico Junior, Marciana Retore, Gessí Ceccon, Isabele Paola de Oliveira Amaral, Ana Carolina Amorim Orrico, Giuliano Reis Pereira Muglia and Tatiane Fernandes

Fermentation 2025, 11(9), 540; https://doi.org/10.3390/fermentation11090540 - 18 Sep 2025

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Abstract

Biomass sorghum stands out for its high dry matter yield and ratooning ability, enabling additional harvests and silage production. This study evaluated the productive potential and fermentation quality of silages from ratoon biomass sorghum hybrids. A 5 × 2 factorial randomized block design [...] Read more.

Biomass sorghum stands out for its high dry matter yield and ratooning ability, enabling additional harvests and silage production. This study evaluated the productive potential and fermentation quality of silages from ratoon biomass sorghum hybrids. A 5 × 2 factorial randomized block design was used, with five hybrids (CMSXS5039, CMSXS5044, CMSXS7102, CMSXS7103, and BRS 716) grown in two municipalities of Mato Grosso do Sul, Brazil (Dourados and Jateí). Dry matter production (DMP) did not differ (p > 0.05) among the hybrids within each municipality; however, overall yield was higher in Jateí, averaging 12 t DM/ha. In Dourados, CMSXS5039 and CMSXS5044 showed the highest lactic acid concentrations (46.71 and 59.73 g/kg DM), whereas in Jateí, CMSXS7102, CMSXS7103, and BRS 716 stood out (45.70, 44.78, and 40.77 g/kg DM, respectively), among the sites, Jateí had the greater lactic acid production (49.95 g/kg DM). Aerobic stability (AS) averaged 28.5 h, with higher values in Dourados (p < 0.05), about 16 h longer than in Jateí. BRS 716 and CMSXS5044 presented the highest crude protein contents (115.17 and 118.33 g/kg DM). CMSXS5039 grown in Jateí had the lowest neutral detergent fiber and the highest starch and non-fiber carbohydrate values. Biomass sorghum hybrids exhibited good yield potential and good silage quality even under low rainfall conditions, with CMSXS5039 best suited for more energetic diets and BRS 716 and CMSXS5044 for more proteic diets. Full article

(This article belongs to the Special Issue Application of Fermentation Technology in Animal Nutrition: 2nd Edition)

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20 pages, 9451 KB

Open AccessArticle

Aeration Rate in Tertiary Treatment of Anaerobic Effluent from Soft Drink Industry by Co-Cultivation Between Penicillium gravinicasei and Microalgae

by João Victor Oliveira Nascimento da Silva, Carlos Eduardo de Farias Silva, Jânio Nunes Sampaio, Bruno Roberto dos Santos, Tácia Souza da Silva, Brígida Maria Villar da Gama, Anderson Correia da Silva, Albanise Enide da Silva and Renata Maria Rosas Garcia Almeida

Fermentation 2025, 11(9), 539; https://doi.org/10.3390/fermentation11090539 - 17 Sep 2025

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Abstract

The soft drink industry generates effluents with high organic loads and contaminants such as nitrogen and phosphorus, requiring sequential secondary and tertiary treatments to meet international discharge standards. Moving beyond traditional monocultures, this study developed a microbial consortium (forming microalga–fungus pellets), demonstrating a [...] Read more.

The soft drink industry generates effluents with high organic loads and contaminants such as nitrogen and phosphorus, requiring sequential secondary and tertiary treatments to meet international discharge standards. Moving beyond traditional monocultures, this study developed a microbial consortium (forming microalga–fungus pellets), demonstrating a synergistic combination due to the resistance of the pellets, enhancing the treatment efficiency, and facilitating the recovery of the microbial sludge produced. Specifically, the treatment of anaerobic effluents (tertiary treatment) from the soft drink industry using consortia of the fungus Penicillium gravinicasei and the microalgae Tetradesmus obliquus and Chlorella sp. in aerated reactors was evaluated, analyzing the impact of aeration rates (0.5–3.5 vvm) on pollutant removal and microbial sludge production. The results showed that moderate aeration rates (1.5 vvm) optimized the removal of COD (up to 92.5%), total nitrogen (TN) (up to 79.3%), and total phosphorus (TP) (up to 83.4%) in just 2.5 h. Furthermore, excessive aeration reduced treatment efficiency due to microbial stress and difficulty in forming microalga–fungus pellets. The Chlorella sp. consortium showed greater stability, while T. obliquus was more sensitive to the aeration rate. Microbial sludge production was also optimized at around 1.5 vvm, consequence of the pollutant removal, with the formation of pellets that facilitated biomass harvesting. Full article

(This article belongs to the Special Issue Cyanobacteria and Eukaryotic Microalgae (2nd Edition))

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40 pages, 1751 KB

Open AccessReview

Lactic Acid Bacteria-Derived Exopolysaccharides: Dual Roles as Functional Ingredients and Fermentation Agents in Food Applications

by Ricardo H. Hernández-Figueroa, Aurelio López-Malo and Emma Mani-López

Fermentation 2025, 11(9), 538; https://doi.org/10.3390/fermentation11090538 - 17 Sep 2025

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Abstract

Exopolysaccharides (EPSs) produced by lactic acid bacteria (LAB) have received special attention as valuable products due to their potential applications as techno-functional and bioactive ingredients in foods. EPS production and consumption are an age-old practice in humans, as evidenced by fermented foods. Over [...] Read more.

Exopolysaccharides (EPSs) produced by lactic acid bacteria (LAB) have received special attention as valuable products due to their potential applications as techno-functional and bioactive ingredients in foods. EPS production and consumption are an age-old practice in humans, as evidenced by fermented foods. Over the last two decades, extensive research has examined, analyzed, and reported a wide variety of EPSs from several LAB strains, as well as their techno-functional properties in foods. Also, research efforts focused on EPS characterization and yield production have been carried out. In food applications, EPS quantification and characterization in situ (direct fermentation) took place in various matrices (dairy, bread, plant-based fermented, and meat products). EPS direct application (ex situ) has been less investigated despite its better structural–functional control and use in non-fermented foods. Fewer EPS investigations have been conducted related to health benefits in humans and their mechanisms of action. The composition and functionality of EPSs vary depending on the LAB strain and food matrix used to produce them; thus, various challenges should be addressed before industrial applications are performed. This review aims to compile and summarize the recent findings on EPSs produced by LAB, highlighting their yield, culture production, techno-functional role in foods, food applications, and health benefits in clinical trials. It examines their dual applications, whether as purified functional ingredients (ex situ) or as fermentation products (in situ), and critically assesses both technological and bioactive implications. Also, it explores production challenges, regulatory considerations, and future perspectives for sustainable and tailored applications of EPSs in food innovation. Full article

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

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20 pages, 1645 KB

Open AccessReview

Smart and Functional Probiotic Microorganisms: Emerging Roles in Health-Oriented Fermentation

by Karina Teixeira Magalhães, Raquel Nunes Almeida da Silva, Adriana Silva Borges, Ana Elisa Barbosa Siqueira, Claudia Puerari and Juliana Aparecida Correia Bento

Fermentation 2025, 11(9), 537; https://doi.org/10.3390/fermentation11090537 - 16 Sep 2025

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Abstract

The incorporation of probiotic microorganisms into fermented foods has long been recognized as a promising strategy to enhance gut health and overall well-being. Conventional probiotics, mainly from the bacterial genera Lactobacillus, Bifidobacterium, Lacticaseibacillus, Levilactobacillus, Lactiplantibacillus and yeast genus Saccharomyces [...] Read more.

The incorporation of probiotic microorganisms into fermented foods has long been recognized as a promising strategy to enhance gut health and overall well-being. Conventional probiotics, mainly from the bacterial genera Lactobacillus, Bifidobacterium, Lacticaseibacillus, Levilactobacillus, Lactiplantibacillus and yeast genus Saccharomyces, contribute to gastrointestinal homeostasis, immune modulation, and metabolic balance. Building on these foundations, recent advances in synthetic biology, systems microbiology, and genetic engineering have enabled the development of smart probiotics: engineered or selectively enhanced strains capable of sensing environmental cues and producing targeted bioactive compounds, such as neurotransmitters and anti-inflammatory peptides. These next-generation microorganisms offer precision functionality in food matrices and hold promise for applications in gastrointestinal health, immune support, and gut–brain axis modulation. However, their deployment also raises critical questions regarding biosafety, regulatory approval, and consumer acceptance. This review provides a comprehensive overview of the mechanisms of action, biotechnological strategies, and health-oriented fermentation applications of smart and functional probiotics, emphasizing their role in the future of personalized and evidence-based functional foods. Full article

(This article belongs to the Special Issue Emerging Microbial Technologies in Fermentation: Innovations in Food, Environmental, and Health Bioprocesses)

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21 pages, 1108 KB

Open AccessArticle

Alternaria, Tenuazonic Acid and Spoilage Yeasts Associated with Bunch Rots of the Southern Oasis of Mendoza (Argentina) Winegrowing Region

by Luciana Paola Prendes, María Gabriela Merín, Fabio Alberto Zamora, Claire Courtel, Gustavo Alberto Vega, Susana Gisela Ferreyra, Ariel Ramón Fontana, María Laura Ramirez and Vilma Inés Morata

Fermentation 2025, 11(9), 536; https://doi.org/10.3390/fermentation11090536 - 15 Sep 2025

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Abstract

A study was carried out to identify the filamentous fungi and yeasts present in rotten wine grapes from two subzones of the Southern oasis of Mendoza winegrowing region, to assess the occurrence of tenuazonic acid (TA), a mycotoxin produced by the Alternaria genus, [...] Read more.

A study was carried out to identify the filamentous fungi and yeasts present in rotten wine grapes from two subzones of the Southern oasis of Mendoza winegrowing region, to assess the occurrence of tenuazonic acid (TA), a mycotoxin produced by the Alternaria genus, and to evaluate the wine spoilage potential of the associated yeasts in vitro and during microvinifications. The main fungal genera present were Alternaria (69.3%), followed by Aspergillus (16.8%), Penicillium (9.3%), and Cladosporium (4.6%), while the dominant yeast species Metschnikowia pulcherrima (23.1%), Aureobasidium pullulans (20.2%) and Hanseniaspora uvarum (13.0%) were followed by H. vineae (11.6%), Zygosaccharomyces bailii (10.4%), and H. guilliermondii (9.2%). Additionally, 94.1% of the rotten samples were contaminated with TA, with the highest level found in the Cabernet Sauvignon variety. No geographic association was found in the incidence of the different fungal genera or yeast species, nor in the occurrence of TA. Almost all of the tested yeasts produced H₂S, the majority of the Hanseniaspora strains produced acetic acid, and only one M. pulcherrima strain produced off-flavours in in vitro tests. Wines co-fermented with H. uvarum L144 and S. cerevisiae showed higher volatile acidity and lower fruity aroma and taste intensity. Therefore, processing bunch rot could pose a toxicological and microbiological risk to winemaking due to the high incidence of Alternaria and TA, as well as the potential of the associated yeasts to spoil wine. Full article

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

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15 pages, 705 KB

Open AccessArticle

Pre-Fermentative Addition of Sodium and Calcium Bentonites on Chardonnay Wine Changes Heat Stability, Fermentation Kinetics, Chemistry, and Volatile Composition

by Miguel A. Pedroza, Sydney Fritsch, Kevin Bargetto and L. Federico Casassa

Fermentation 2025, 11(9), 535; https://doi.org/10.3390/fermentation11090535 - 13 Sep 2025

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Abstract

Protein stabilization in white wines commonly involves bentonite fining, yet the influence of bentonite type, dosage, and pre-fermentative treatment on wine composition and fermentation remains underexplored. This study assessed the effects of pre-fermentative additions of sodium and calcium bentonites at three dosage levels [...] Read more.

Protein stabilization in white wines commonly involves bentonite fining, yet the influence of bentonite type, dosage, and pre-fermentative treatment on wine composition and fermentation remains underexplored. This study assessed the effects of pre-fermentative additions of sodium and calcium bentonites at three dosage levels (24, 48, and 72 g/hL) on the fermentation kinetics, protein (heat) stability, and chemical and aromatic composition of Chardonnay wines under commercial winemaking conditions. Sodium bentonite at 72 g/hL achieved near-complete protein stabilization (ΔNTU = 3), while all calcium bentonite treatments required significantly higher cumulative dosages (up to 216 g/hL). Pre-fermentative bentonite additions led to modest reductions in primary amino nitrogen (up to 13.2 mg/L), resulting in extended alcoholic fermentation durations by up to 33 h and variable delays in malolactic fermentation across treatments. Volatile ester analysis revealed limited sensory impact, with isoamyl acetate showing the greatest reduction (up to −2.8 odor activity value; −39%) at higher bentonite levels, whereas ethyl decanoate remained largely unaffected. Overall, the pre-fermentative addition of sodium bentonite at 72 g/hL provided an effective strategy to reduce the need for post-fermentation fining while preserving key chemical and aromatic attributes of Chardonnay wine. Full article

(This article belongs to the Special Issue Science and Technology of Winemaking)

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18 pages, 2094 KB

Open AccessArticle

The Construction of Corynebacterium glutamicum for Producing γ-Aminobutyric Acid and Analysis of the Fermentation Process

by Qijie Deng, Ying Wen, Runmei Zhang and Jun Cai

Fermentation 2025, 11(9), 534; https://doi.org/10.3390/fermentation11090534 - 13 Sep 2025

Viewed by 563

Abstract

In this study, we constructed a recombinant Corynebacterium glutamicum strain for γ-aminobutyric acid (GABA) biosynthesis via the heterologous expression of glutamate decarboxylase (GAD) derived from Lactiplantibacillus plantarum. We systematically analyzed the fermentation strategy, the balance between cell growth and GAD expression, and [...] Read more.

In this study, we constructed a recombinant Corynebacterium glutamicum strain for γ-aminobutyric acid (GABA) biosynthesis via the heterologous expression of glutamate decarboxylase (GAD) derived from Lactiplantibacillus plantarum. We systematically analyzed the fermentation strategy, the balance between cell growth and GAD expression, and the intracellular and extracellular glutamate and GABA levels during fermentation in recombinant C. glutamicum. The results demonstrated that a fermentation strategy combining variable-rate feeding with two-stage pH control at an initial glucose concentration of 50 g/L effectively enhanced cell proliferation, facilitated continuous glutamate synthesis and improved the catalytic efficiency of GAD. The intracellular and extracellular GABA synthesis improved up to 3.231 ± 0.024 g/L (a six-fold increase compared to the uncontrolled supplementation conditions). Furthermore, we fitted empirical equations relating cell growth, glucose consumption, GAD activity, and GABA synthesis during the fermentation. The maximum specific growth rate, glucose consumption rate, and GABA synthesis rate of recombinant C. glutamicum were 0.316 h⁻¹, 1.407 g/(g∙h), and 0.0697 g/L/h, respectively. The fermentation regulation strategy and the dynamic analysis of the fermentation process in this study provide support for future metabolic regulation strategies. Full article

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

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19 pages, 7933 KB

Open AccessArticle

Optimized Co-Fermentation of Seed Melon and Z. bungeanum Seed Meal with Saccharomyces cerevisiae L23: Valorization into Functional Feed with Enhanced Antioxidant Activity

by Liping Lu, Xue Zhang, Ziyi Yin, Rui Zhou, Yanli Zhu, Shanshan Liu and Dandan Gao

Fermentation 2025, 11(9), 533; https://doi.org/10.3390/fermentation11090533 - 12 Sep 2025

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Abstract

This study aimed to enhance the value of agricultural by-products by developing seed melon compound fermented feed (SMFF) using Saccharomyces cerevisiae L23. A two-stage optimization strategy was implemented. First, seed melon juice seed culture medium (SMCM) composition and fermentation conditions were optimized to [...] Read more.

This study aimed to enhance the value of agricultural by-products by developing seed melon compound fermented feed (SMFF) using Saccharomyces cerevisiae L23. A two-stage optimization strategy was implemented. First, seed melon juice seed culture medium (SMCM) composition and fermentation conditions were optimized to maximize S. cerevisiae L23 biomass through single-factor and response surface methodology (RSM) approaches. The SMCM medium was optimized to contain 0.06% MgSO₄·7H₂O, 0.2% KH₂PO₄, 0.65% (NH₄)₂SO₄, 0.1% pectinase, and 1.0% urea, and fermentation conditions with inoculation amount, fermentation time, fermentation temperature, and glucose addition were 6%, 28 h, 30 °C, and 0.5%, respectively. Furthermore, SMFF fermentation parameters were optimized via RSM, achieving S. cerevisiae L23 (10.35 lg CFU/g) and sensory evaluation score (83.1) at substrate ratio of 7:3 (seed melon juice: Zanthoxylum bungeanum seed meal), inoculation amount of 8%, and fermentation time of 36 h. Fermentation process significantly improved the nutritional profile of SMFF, increasing crude protein (13%) and vitamin C (VC) content (21%) while reducing neutral detergent fiber/acid detergent fiber (NDF/ADF) levels. SMFF also improved in vitro antioxidant capacity, with higher DPPH, ABTS, hydroxyl radical, and superoxide anion scavenging activities compared to SMFF control. This process efficiently valorized agricultural by-products into nutritionally enriched functional feed. Full article

(This article belongs to the Section Fermentation Process Design)

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20 pages, 4583 KB

Open AccessArticle

Seasonal Temperature Effects on EPS Composition and Sludge Settling Performance in Full-Scale Wastewater Treatment Plant: Mechanisms and Mitigation Strategies

by Fei Xie, Chenzhe Tian, Xiao Ma, Li Ji, Bowei Zhao, Muhammad Ehsan Danish, Feng Gao and Zhihong Yang

Fermentation 2025, 11(9), 532; https://doi.org/10.3390/fermentation11090532 - 12 Sep 2025

Viewed by 493

Abstract

Seasonal temperature variations significantly impact biological wastewater treatment performance, particularly affecting extracellular polymeric substance (EPS) composition and sludge settling characteristics in activated sludge systems. This study investigated the temperature-induced EPS response mechanisms and their effects on nitrogen removal efficiency in a full-scale modified [...] Read more.

Seasonal temperature variations significantly impact biological wastewater treatment performance, particularly affecting extracellular polymeric substance (EPS) composition and sludge settling characteristics in activated sludge systems. This study investigated the temperature-induced EPS response mechanisms and their effects on nitrogen removal efficiency in a full-scale modified Bardenpho wastewater treatment plant, combined with laboratory-scale evaluation of EPS-optimizing microbial agents for performance enhancement. Nine-month seasonal monitoring revealed that when the wastewater temperature dropped below 15 °C, the total nitrogen (TN) removal efficiency decreased from 86.5% to 80.6%, with a trend of significantly increasing polysaccharides (PS) in dissolved organic matter (DOM) and loosely-bound EPS (LB-EPS) and markedly decreasing tightly-bound EPS (TB-EPS). During the low-temperature periods, when the sludge volume index (SVI) exceeded 150 mL/g, deteriorated settling performance could primarily be attributed to the reduced TB-EPS content and increased LB-EPS accumulation. Microbial community analysis showed that EPS secretion-promoting genera of Trichococcus, Terrimonas, and Defluviimonas increased during the temperature recovery phase rather than initial temperature decline phase. Laboratory-scale experiments demonstrated that EPS-optimizing microbial agents dominated by Mesorhizobium (54.2%) effectively reduced protein (PN) and PS contents in LB-EPS by 70.2% and 54.5%, respectively, while maintaining stable nutrient removal efficiency. These findings provide mechanistic insights into temperature–EPS interactions and offer practical technology for improving winter operation of biological wastewater treatment systems. Full article

(This article belongs to the Section Industrial Fermentation)

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20 pages, 1067 KB

Open AccessArticle

A Potential of Agro-Industrial Biowaste as Low-Cost Substrates for Carotenoid Production by Rhodotorula mucilaginosa

by Olja Šovljanski, Dragoljub Cvetković, Tara Budimac, Anja Vučetić, Ana Tomić, Teodora Marić and Aleksandra Ranitović

Fermentation 2025, 11(9), 531; https://doi.org/10.3390/fermentation11090531 - 12 Sep 2025

Viewed by 495

Abstract

The sustainable production of natural pigments is gaining attention as industries seek alternatives to synthetic additives. This study explored agro-industrial biowastes as feedstocks for carotenoid biosynthesis by Rhodotorula mucilaginosa (natural isolate from Jerusalem artichoke), aiming to identify an optimal substrate that combines high [...] Read more.

The sustainable production of natural pigments is gaining attention as industries seek alternatives to synthetic additives. This study explored agro-industrial biowastes as feedstocks for carotenoid biosynthesis by Rhodotorula mucilaginosa (natural isolate from Jerusalem artichoke), aiming to identify an optimal substrate that combines high productivity with economic and environmental feasibility. Thirteen biowastes, including grape pomace, crude glycerol, chicken feathers, sugar beet juice, and pea protein isolate, were systematically evaluated for their impact on yeast growth and pigment accumulation. Carotenoid yields ranged from 21.4 to 187.2 mg/100 g dry weight, with the highest volumetric productivity achieved in pea protein isolate (14.98 mg/L), untreated white grape pomace (14.09 mg/L), and crude glycerol (13.87 mg/L). To assess scalability, a simplified techno-economic and sustainability analysis was applied, revealing that although pea protein isolate offered the best yields, its high market cost limited industrial feasibility. In contrast, untreated grape pomace and crude glycerol emerged as low-cost, abundant alternatives with strong circular bioeconomy potential. Fed-batch bioreactor validation using untreated grape pomace confirmed its suitability, achieving a 43% improvement in carotenoid productivity (20.1 mg/L) compared to shake-flask trials. These results position untreated grape pomace as the optimal substrate–strategy combination for sustainable carotenoid production linking agro-waste valorization with high-value bioproduct generation. This study provides both experimental evidence and economic rationale for integrating winery residues into industrial pigment production chains, advancing yeast biotechnology toward more circular and resource-efficient models. Full article

(This article belongs to the Special Issue Yeasts as Microbial Cell Factories: Diversity, Biotechnology Potential and Applications)

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18 pages, 10388 KB

Open AccessArticle

Effect of Inoculation of Lactic Acid Bacteria and Fibrolytic Enzymes on Microbiota in the Terminal and Aerobically Exposed Short-Growing Season Whole-Plant Corn Silage

by Chunli Li, Jayakrishnan Nair, Eric Chevaux, Tim A. McAllister and Yuxi Wang

Fermentation 2025, 11(9), 530; https://doi.org/10.3390/fermentation11090530 - 10 Sep 2025

Viewed by 536

Abstract

An experiment was conducted to evaluate the effects of mixed lactic acid bacteria (LAB) plus fibrolytic enzymes (xylanase + β-glucanase) on bacterial and fungal communities in terminal and aerobically exposed whole-plant corn silage ensiled in a temperate zone. Short-season corn forage was either [...] Read more.

An experiment was conducted to evaluate the effects of mixed lactic acid bacteria (LAB) plus fibrolytic enzymes (xylanase + β-glucanase) on bacterial and fungal communities in terminal and aerobically exposed whole-plant corn silage ensiled in a temperate zone. Short-season corn forage was either uninoculated (C) or inoculated (I) with a mixture of LAB containing 1.5 × 10⁵ colony-forming units (cfu)/g Lentilactobacillus hilgardii, 1.5 × 10⁵ cfu/g of Lentilactobacillus buchneri, and 1.0 × 10⁵ cfu/g Pediococcus pentosaceus plus a combination of xylanase + β-glucanase. Silage samples were taken after ensiling in bag silos for 418 days (terminal silage; TS), with subsamples of TS subsequently exposed to air for 14 days (aerobically exposed silage; AS). Regardless of treatment, Firmicutes, Proteobacteria, Cyanobacteria, and Actinobacteria were the predominant phyla in the bacterial microbiome, whilst Ascomycota and Basidiomycota were the predominant phyla in the fungal microbiome in both TS and AS. Lactobacillus, Acetobacter, and Bacillus were the most abundant bacterial genera, whilst Candida, Aspergillus, Vishniacozyma, Pichia, and Issatchenkia were the most abundant fungal genera. Use of silage additive did not change bacterial or fungal alpha or beta diversity during ensiling or aerobic exposure, but decreased (p < 0.01) the relative abundance (RA) of Proteobacteria in both TS and AS, increased (p < 0.01) RA of Firmicutes in AS, but did not affect the RA of fungal phyla in either TS or AS. At the genus level, the additive significantly decreased (p < 0.01) RA of Acetobacter in both TS and AS. The silage additive used in this study significantly affected the composition of multiple microbial genera during ensiling and aerobic exposure by shifting bacterial communities towards enhanced aerobic stability. Full article

(This article belongs to the Special Issue The Use of Lactobacillus in Forage Storage and Processing, 2nd Edition)

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14 pages, 578 KB

Open AccessArticle

Application of Hops (Humulus lupulus L.) and β-Acid Extract to Improve Aerobic Stability and In Vitro Ruminal Fermentation of Maralfalfa Grass Silage

by Lianne Romero-Vilorio, Bexy González-Mora, Yamicela Castillo-Castillo, Francisco Castillo-Rangel, Einar Vargas-Bello-Perez, Joel Dominguez-Viveros, Monserrath Felix-Portillo, Robin C. Anderson, Michael E. Hume, Michael D. Flythe, Omar G. Nájera-Pedraza, Jaime Salinas-Chavira and Oscar Ruiz-Barrera

Fermentation 2025, 11(9), 529; https://doi.org/10.3390/fermentation11090529 - 10 Sep 2025

Viewed by 492

Abstract

The potential of hops (Humulus lupulus L.) and β-acid extract were evaluated for improving the quality of maralfalfa grass (Cenchrus purpureus) silage (with added sorghum grain, sorghum straw, and urea) during aerobic exposure and their residual effects on in vitro [...] Read more.

The potential of hops (Humulus lupulus L.) and β-acid extract were evaluated for improving the quality of maralfalfa grass (Cenchrus purpureus) silage (with added sorghum grain, sorghum straw, and urea) during aerobic exposure and their residual effects on in vitro ruminal fermentation characteristics. Silage samples and ground hops pellets (Galena and Chinook varieties) as well as β-acid mixtures were incubated at 37 °C for 24 h and then maintained under aerobic exposure for 12 h. The sample pH, counts of filamentous fungi, yeasts, and total coliforms, and volatile fatty acid (VFA) concentrations were determined. Subsequently, in vitro ruminal fermentation was conducted to determine total gas production and concentrations of hydrogen, methane, carbon dioxide, and VFAs. The β-acid treatment controlled yeast populations, but an increase (p < 0.05) in pH values was observed for the Galena and Chinook treatments compared to the Control. However, pH did not differ significantly (p > 0.05) between the Control and the β-acid treatment. Butyric acid concentrations in the silage were lower (p < 0.05) compared to the Control, except in the silage treatment with Galena. In the in vitro ruminal fermentation, the β-acid treatment showed higher butyric acid levels than the Chinook and Galena, but these differences were not significant (p > 0.05). There were no differences (p > 0.05) in methane between the treatments. An increase (p < 0.05) in propionic acid concentration was observed in the in vitro ruminal fermentation with β-acids. It was concluded that β-acids could help reduce silage deterioration during the aerobic phase, reducing the butyric acid and yeast populations, and their residual effect could improve ruminal fermentation, increasing propionate and acetate concentrations. Full article

(This article belongs to the Special Issue Fermentation Technologies for the Production of High-Quality Feed: 2nd Edition)

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14 pages, 5867 KB

Open AccessReview

Fermentation of Organic Wastes for Feed Protein Production: Focus on Agricultural Residues and Industrial By-Products Tied to Agriculture

by Dan He and Can Cui

Fermentation 2025, 11(9), 528; https://doi.org/10.3390/fermentation11090528 - 10 Sep 2025

Viewed by 616

Abstract

Global population growth and dietary transition have intensified demand for livestock and aquaculture products, thereby escalating demand for high-quality animal feed. Conventional protein sources, including soybean meal and fishmeal, face severe supply constraints driven by intense competition for arable land, worsening water scarcity, [...] Read more.

Global population growth and dietary transition have intensified demand for livestock and aquaculture products, thereby escalating demand for high-quality animal feed. Conventional protein sources, including soybean meal and fishmeal, face severe supply constraints driven by intense competition for arable land, worsening water scarcity, overexploitation of fishery resources, and rising production costs. These challenges are especially pronounced within agricultural systems. Evidence demonstrates that converting agriculturally derived organic wastes and agri-industrial by-products into feed protein can simultaneously alleviate these pressures, address agricultural waste disposal challenges, and reduce the carbon footprint associated with agricultural production. This review synthesizes fermentation processes for generating feed protein from agricultural organic wastes by employing functionally adapted microorganisms or microbial consortia. This distinguishes it from prior studies, which focused solely on single waste streams or individual microbial strains. It aims to advance feed protein production through an integrated approach that unites agricultural organic wastes, microorganisms, and fermentation processes, thereby promoting resource-oriented utilization of agricultural organic wastes and providing actionable solutions to alleviate feed protein scarcity. Full article

(This article belongs to the Special Issue Valorisation of Agro-Industrial By-Products Through Fermentation or Eco-Friendly Techniques)

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14 pages, 4497 KB

Open AccessArticle

Fungifuels: Polyethylene Decomposition and Electricity Generation with Aspergillus ochraceopetaliformis in Microbial Fuel Cell Systems

by Rojas-Flores Segundo, Magaly De La Cruz-Noriega, Nancy Soto-Deza, Nélida Milly Otiniano, Cabanillas-Chirinos Luis and Anibal Alviz-Meza

Fermentation 2025, 11(9), 527; https://doi.org/10.3390/fermentation11090527 - 9 Sep 2025

Viewed by 736

Abstract

Plastic pollution is an increasingly pressing environmental concern due to its persistence in ecosystems. To address this issue, this study evaluates polyethylene biodegradation and bioelectricity generation using Aspergillus ochraceopetaliformis in microbial fuel cells (MFCs). Single-chamber MFCs were designed (three) with carbon and zinc [...] Read more.

Plastic pollution is an increasingly pressing environmental concern due to its persistence in ecosystems. To address this issue, this study evaluates polyethylene biodegradation and bioelectricity generation using Aspergillus ochraceopetaliformis in microbial fuel cells (MFCs). Single-chamber MFCs were designed (three) with carbon and zinc electrodes, where the fungus was cultivated in a nutrient-rich medium to enhance its metabolic activity. Parameters such as pH, power density, and FTIR spectra were monitored to assess plastic biodegradation. The results demonstrated a significant reduction in polyethylene mass and structure, along with a maximum generation of 0.921 V and 4.441 mA on day 26, with a power density of 0.148 mW/cm² and a current of 5.847 mA/cm². The optimal pH for fungal activity in the MFC was recorded at 7.059. Furthermore, FTIR analysis revealed a decrease in peak intensity at 1470 cm⁻¹ and 723 cm⁻¹, indicating structural modifications in the treated plastics. Furthermore, microbial fuel cells connected in series successfully powered an LED bulb, generating a maximum voltage of 2.78 V. These findings confirm the feasibility of using Aspergillus ochraceopetaliformis for biodegradation and bioelectricity generation, although practical applications require further optimization of system conditions and improvements in long-term stability. This research contributes to the development of biotechnological strategies for plastic waste management, sustainable integrating approaches with energy potential. Full article

(This article belongs to the Section Industrial Fermentation)

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20 pages, 6133 KB

Open AccessArticle

PerR Deletion Enhances Oxygen Tolerance and Butanol/Acetone Production in a Solvent-Degenerated Clostridium beijerinckii Strain DS

by Chuan Xiao, Jianxiong Dou, Naan Zhang, Laizhuang Liu, Shengjie Du, Xiancai Rao and Longjiang Yu

Fermentation 2025, 11(9), 526; https://doi.org/10.3390/fermentation11090526 - 8 Sep 2025

Viewed by 1267

Abstract

The industrial potential of Clostridium beijerinckii for acetone–butanol–ethanol (ABE) fermentation is limited by oxygen sensitivity and suboptimal solvent productivity. Peroxide repressor (PerR), a key negative regulator protein, is reported to suppress the oxidative stress defense system in anaerobic clostridia, leading to poor survival [...] Read more.

The industrial potential of Clostridium beijerinckii for acetone–butanol–ethanol (ABE) fermentation is limited by oxygen sensitivity and suboptimal solvent productivity. Peroxide repressor (PerR), a key negative regulator protein, is reported to suppress the oxidative stress defense system in anaerobic clostridia, leading to poor survival of bacteria under aerobic conditions. However, the regulatory mechanism underlying this phenomenon remains unclear. This study demonstrates that targeted deletion of perR (Cbei_1336) in the solvent-deficient strain C. beijerinckii DS confers robust oxygen tolerance and enhances ABE fermentation performance. The engineered perR mutant exhibited unprecedented aerobic growth under atmospheric oxygen (21% O₂), achieving a (3.79 ± 0.09)-fold increase in biomass accumulation, a (2.84 ± 0.12)-fold improvement in glucose utilization efficiency, a (57.23 ± 0.01)-fold elevation in butanol production, and a (32.78 ± 0.02)-fold amplification in acetone output compared to the parental strain. Transcriptomic analysis revealed that perR knockout simultaneously upregulated oxidative defense systems and activated ABE pathway-related genes. This genetic rewiring redirected carbon flux from acidogenesis to solventogenesis, yielding a (9.64 ± 0.90)-fold increase in total solvent titer (15.61 ± 0.89 vs. 1.62 ± 0.12 g/L) and a (2.71 ± 0.04)-fold rise in volumetric productivity (0.19 ± 0.01 vs. 0.07 ± 0.01 g/L/h). Our findings establish PerR as a master regulator of both oxygen resilience and metabolic reprogramming, providing a scalable engineering strategy for industrial oxygen-tolerant ABE bioprocessing toward low-cost biobutanol production. Full article

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

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14 pages, 3172 KB

Open AccessArticle

Transforming Tilapia into Indoleacetic Acid-Containing Biostimulants: Synergistic Effect of Enzymolysis and Multi-Strain Fermentation

by Hanyi Xie, Bin Zhong, Qimin Zhang, Xi Hu, Xuesen Xia, Hong Xie and Zhenqiang Wu

Fermentation 2025, 11(9), 525; https://doi.org/10.3390/fermentation11090525 - 8 Sep 2025

Viewed by 494

Abstract

Following new trends in green development, many studies have focused on the high-value utilization of fish resources through green biological processes. This study innovatively introduced a one-step process of mixed strain–enzyme synergy (MES) with which to prepare tilapia hydrolysates and explored the synergistic [...] Read more.

Following new trends in green development, many studies have focused on the high-value utilization of fish resources through green biological processes. This study innovatively introduced a one-step process of mixed strain–enzyme synergy (MES) with which to prepare tilapia hydrolysates and explored the synergistic effects of strains and enzymes on both the protein hydrolysis process and its products’ characteristics via comparative experiments. Further, soybean was used as a model crop to verify the agronomic effects of the hydrolysates. The addition of exogenous papain increased hydrolysis by 31.94% compared to the fermentation-only group. Peptides and amino acids contents in the mixed strains were higher than those in the single fermentation process (p < 0.05), while 8.46 mg/L of indoleacetic acid was produced through fermentation. Hydrolysates promoted the growth of lateral roots in soybean seedlings (p < 0.05) via the use of a 2500-fold dilution of the biostimulant, increasing the root area and stem length and reducing the sugar content of soybean seedlings by 1.59-, 1.44- and 1.69-fold compared to those in Hoagland’s nutrient solution. These results lay a foundation for the biological preparation of biostimulants for hydroponic vegetables through the utilization of fish waste resources, aligning with green development goals. Full article

(This article belongs to the Special Issue Fermentation of Organic Waste for High-Value-Added Product Production—2nd Edition)

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16 pages, 2374 KB

Open AccessArticle

Production of Nutritional Protein Hydrolysates by Fermentation of Black Soldier Fly Larvae

by Penghui Zhang, Kelyn Seow, Leo Wein, Rachel Steven, Rebecca J. Case, Yulan Wang and Patricia L. Conway

Fermentation 2025, 11(9), 524; https://doi.org/10.3390/fermentation11090524 - 8 Sep 2025

Viewed by 656

Abstract

The black soldier fly (Hermetia illucens) has become one of the most promising alternative protein sources in the feed and food industry. The aim of this work was to utilize microbial fermentation to enhance the nutritional properties of black soldier fly [...] Read more.

The black soldier fly (Hermetia illucens) has become one of the most promising alternative protein sources in the feed and food industry. The aim of this work was to utilize microbial fermentation to enhance the nutritional properties of black soldier fly larvae (BSFL) as a food ingredient for human consumption by optimizing the amino acid profile and small peptide content. Free amino acids (FAA) have a critical role in human nutrition and bioavailability. Unlike whole proteins that require enzymatic breakdown in the digestive tract, FAA are directly absorbable by the small intestine, allowing for rapid utilization in protein synthesis and metabolic functions. BSFL pastes were fermented using Lacticaseibacillus paracasei (PCB 030) or a mixed starter culture preparation, and results were compared to pea protein and BSFL pastes that were enzymatically hydrolyzed. The resultant hydrolyzed BSFL pastes were analyzed for free amino acids and small peptides. The L. paracasei PCB 030 fermented BSFL pastes yielded significantly higher amounts of free amino acids than the control or pastes fermented using a commercial starter culture (named F-LC). The increased FAA availability in fermented BSFL makes it a more efficient protein source for human consumption. The L. paracasei PCB 030 fermented pastes showed an increase in small peptides after three days fermentation; nearly 80% of normalized abundances of small peptides increased by over 100 times compared to day zero (before the fermentation started). Over 90% of these small peptides consisted of more than 50% hydrophobic amino acids, which may contribute to their antioxidant and antibacterial properties. This study provides a promising and industrially practical process for hydrolyzing BSFL protein to yield a functional protein hydrolysate with an enhanced nutritional profile. Full article

(This article belongs to the Special Issue 10th Anniversary of Fermentation: Feature Papers in the "Fermentation for Food and Beverages" Section)

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16 pages, 505 KB

Open AccessArticle

Direct Application of Fermented Solid Containing Lipases from Pycnoporus sanguineus in Esterification Reactions and Kinetic Resolution of Sec-alcohols

by Alexsandra Nascimento Ferreira, Leandro Alves dos Santos, Glêydison Amarante Soares, Márcia Soares Gonçalves, Simone Andrade Gualberto, Marcelo Franco, Lílian Márcia Dias dos Santos, Francis Soares Gomes, Melissa Fontes Landell and Hugo Juarez Vieira Pereira

Fermentation 2025, 11(9), 523; https://doi.org/10.3390/fermentation11090523 - 5 Sep 2025

Viewed by 694

Abstract

Lipases are widely used as biocatalysts in synthetic applications because of their high chemo-, regio-, and enantioselectivities, which play key roles in the synthesis of esters and the resolution of racemates. These biocatalytic steps are essential for the production of various products, including [...] Read more.

Lipases are widely used as biocatalysts in synthetic applications because of their high chemo-, regio-, and enantioselectivities, which play key roles in the synthesis of esters and the resolution of racemates. These biocatalytic steps are essential for the production of various products, including cosmetic ingredients, building blocks in the pharmaceutical and agrochemical industries. In this study, we produced lipases through solid-state fermentation of agricultural by-products and domestic wastes using the fungus Pycnoporus sanguineus. After fermentation, the dried solids containing lipases from P. sanguineus exhibited high catalytic activity. Lipase production was achieved via solid-state fermentation using a substrate composed of wheat bran and sugarcane bagasse supplemented with either residual frying oil or urea, resulting in an enzymatic activity of 24 U mL⁻¹ after 96 h. The resulting P. sanguineus fermentation solids (PSFS) efficiently catalyzed the esterification of capric acid with ethanol, achieving 95% ester conversion within 28 h. Additionally, PSFS proved to be effective in the kinetic resolution of (RS)-1-phenyl-1-ethanol via transesterification with various acyl donors, selectively forming the (R)-enantiomer. This process yielded a 16% conversion to (R)-1-phenylethyl propionate and an enantiomeric ratio (E) exceeding 200 after 72 h. These results demonstrate the potential of PSFS for applications in ester synthesis and resolution of enantiomerically pure sec-alcohols. Full article

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

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15 pages, 1783 KB

Open AccessArticle

Effect of Harvesting Time on Starch Degradation in Rumen of Whole-Plant Corn and Its Silage

by Long Zhang, Shiqin Liu, Xuepeng Wang, He Wang, Songze Li, Yuguo Zhen and Xuefeng Zhang

Fermentation 2025, 11(9), 522; https://doi.org/10.3390/fermentation11090522 - 4 Sep 2025

Viewed by 530

Abstract

Whole-plant corn silage is a critical feedstuff in global ruminant production, and its nutrient composition is closely tied to harvest timing. As starch acts as the primary energy source in silage-based diets, investigating changes in starch degradation rate provides a theoretical basis for [...] Read more.

Whole-plant corn silage is a critical feedstuff in global ruminant production, and its nutrient composition is closely tied to harvest timing. As starch acts as the primary energy source in silage-based diets, investigating changes in starch degradation rate provides a theoretical basis for optimizing the efficient utilization of whole-plant corn and its silage in ruminant production. In this study, whole-plant corn (harvested from the milk stage to full ripening stage) and its corresponding silage were used as experimental materials. An in vitro simulated rumen fermentation system was employed to determine the contents of starch, prolamin, amylose, and amylopectin in the samples. The results showed that with delayed harvest time, starch content in both whole-plant corn and its silage increased significantly; prolamin and amylose contents first decreased, then increased; amylopectin content first rose significantly before decreasing; and both starch disappearance rate and speed exhibited a trend of first increasing, then decreasing. After silage fermentation, the silage had significant increases in starch, amylose, and amylopectin contents, and starch disappearance rate; prolamin content decreased; and starch disappearance speed increased extremely significantly. This study indicates that whole-plant corn harvest time and silage fermentation regulate the ruminal starch degradation pattern by altering starch structure, prolamin content, and the proportion of rapidly degradable starch. Full article

(This article belongs to the Special Issue Application of Fermentation Technology in Animal Nutrition: 2nd Edition)

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19 pages, 1408 KB

Open AccessArticle

Yellow Pea Flour Fermented with Kefir as a Valuable Ingredient for the Techno-Functional and Sensory Improvement of Gluten-Free Bread

by Débora N. López, Pamela S. Forastieri, Natalia L. Calvo, María Belén Cossia, Camila Tedaldi, Emilce E. Llopart, María Eugenia Steffolani and Valeria Boeris

Fermentation 2025, 11(9), 521; https://doi.org/10.3390/fermentation11090521 - 4 Sep 2025

Cited by 1 | Viewed by 656

Abstract

This work studies yellow pea flour (YPF) fermentation with kefir (1:1.5 mass ratio, incubated 30 h at 25 °C) for gluten-free breadmaking. Three samples were evaluated: untreated YPF, YPF mixed with kefir (UF), and fermented YPF (FF). Structural changes were minimal, but fermentation [...] Read more.

This work studies yellow pea flour (YPF) fermentation with kefir (1:1.5 mass ratio, incubated 30 h at 25 °C) for gluten-free breadmaking. Three samples were evaluated: untreated YPF, YPF mixed with kefir (UF), and fermented YPF (FF). Structural changes were minimal, but fermentation improved the flour functionality. Bulk density (g/mL) decreased from 0.54 ± 0.02 in YPF and 0.47 ± 0.01 in UF to 0.43 ± 0.01 in FF, while the water absorption capacity (g/g) increased from 1.20 ± 0.01 in YPF and 1.50 ± 0.05 in UF to 1.92 ± 0.02 in FF. YPF showed the lowest oil absorption capacity (0.90 ± 0.02 g/g), while higher values were obtained for FF and UF (averaging 1.54 g/g). The yellowness index showed a clear tendency: higher in UF (34.9 ± 0.2), intermediate in FF (32.869 ± 0.008), and lower in YPF (22.4 ± 0.1). In gluten-free bread, baking loss did not show significant differences between FF-B and UF-B (averaging 15.65%) but they were significantly lower than that of YPF-B (18.5 ± 0.5%). The highest specific volume (mL/g) was observed in FF-B (1.96 ± 0.02), followed by UF-B (1.33 ± 0.02) and YPF-B (1.08 ± 0.02). Significantly reduced “pea” sensory attributes were perceived in FF-B, while acidity perception increased. Hardness was similar among breads, although chewiness was higher in FF-B. These results suggest that kefir fermentation enhances YPF functionality in gluten-free breadmaking. Full article

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

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17 pages, 5197 KB

Open AccessArticle

Growth Kinetics and Extracellular Enzyme Secretion of Aureobasidium pullulans m11-2 as an Alternative Source of Polysaccharidases for Winemaking

by María Eugenia Sevillano, Vilma Inés Morata and María Carolina Martín

Fermentation 2025, 11(9), 520; https://doi.org/10.3390/fermentation11090520 - 3 Sep 2025

Viewed by 670

Abstract

Microbial enzymes, due to their efficiency, specificity, and sustainability, are central to innovative biotechnological strategies aimed at optimizing industrial processes such as winemaking. In this study, the potential of Aureobasidium pullulans m11-2, a native dimorphic fungus from the wine ecosystem, was evaluated as [...] Read more.

Microbial enzymes, due to their efficiency, specificity, and sustainability, are central to innovative biotechnological strategies aimed at optimizing industrial processes such as winemaking. In this study, the potential of Aureobasidium pullulans m11-2, a native dimorphic fungus from the wine ecosystem, was evaluated as a source of hydrolytic enzymes capable of degrading grape cell wall polysaccharides. The strain was identified at the molecular level and characterised in terms of its morphology. To maximise enzyme production, various culture media were tested. Among the concentrations tested, the optimal levels of glucose and pectin were 1 g L⁻¹ and 10 g L⁻¹, respectively. The partially constitutive and inducible nature of the various polysaccharidase activities (pectinases, cellulases, and xylanases) was confirmed. The effect of grape skins (a winemaking by-product) on microbial growth and enzyme synthesis was evaluated, achieving a pectinase activity of 0.622 U mL⁻¹ when combined with 1 g L⁻¹ of glucose. Maximum enzyme yields were detected during the exponential growth phase in both citrus pectin and grape skin media, suggesting favorable conditions for continuous bioprocessing. These results confirm that A. pullulans m11-2 is an interesting microbial option for producing polysaccharidases that can be adapted to sustainable production systems. Full article

(This article belongs to the Special Issue Microbial Production of Industrial Enzymes)

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18 pages, 3334 KB

Open AccessArticle

Characterization of a Hyaluronidase from Paenibacillus residui BSSK58 and Evaluation of Its Industrial Applicability

by Jung-Soo Park, Hyewon Choe, Ji Sun Kim, Hyun Ho Lee, Seogwon Lee, Joo-Woong Park and Jin Ree

Fermentation 2025, 11(9), 519; https://doi.org/10.3390/fermentation11090519 - 3 Sep 2025

Viewed by 726

Abstract

Hyaluronidase is a hydrolytic enzyme that cleaves β-1,4-glycosidic linkages in high-molecular-weight hyaluronic acid, generating low-molecular-weight oligosaccharides with enhanced biological functions. These products exhibit immunomodulatory, antioxidant, and tissue-regenerative properties, making them valuable in pharmaceutical, cosmetic, and functional food applications. However, most commercial hyaluronidases originate [...] Read more.

Hyaluronidase is a hydrolytic enzyme that cleaves β-1,4-glycosidic linkages in high-molecular-weight hyaluronic acid, generating low-molecular-weight oligosaccharides with enhanced biological functions. These products exhibit immunomodulatory, antioxidant, and tissue-regenerative properties, making them valuable in pharmaceutical, cosmetic, and functional food applications. However, most commercial hyaluronidases originate from pathogenic bacteria or recombinant hosts, raising concerns over their biosafety and regulatory acceptance, particularly in food-grade applications. In this study, we report the isolation and characterization of a novel non-pathogenic soil bacterium, Paenibacillus residui BSSK58, which produces an extracellular hyaluronidase. Whole-genome sequencing revealed the absence of known virulence factors and antibiotic resistance genes. Phenotypic safety evaluations confirmed that there was no hemolytic activity, biogenic amine production, or cytotoxicity against human intestinal epithelial cell lines (Caco-2 and HT-29). The purified BSSK58 hyaluronidase exhibited a molecular weight of approximately 170 kDa, with optimal activity at pH 8.0–9.0 and 50 °C. The enzyme showed broad substrate specificity toward hyaluronic acid, chondroitin sulfate, and alginate, and its depolymerizing activity was confirmed using gel permeation chromatography. Furthermore, a 13-week oral repeated-dose toxicity study under Good Laboratory Practice conditions demonstrated no adverse effects. These findings support the use of BSSK58 hyaluronidase as a safe, non-recombinant biocatalyst suitable for industrial applications under regulatory-compliant frameworks. Full article

(This article belongs to the Section Industrial Fermentation)

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Open AccessArticle

Monensin Degradation and Methane Production from Sugarcane Vinasse in Two-Phase Thermophilic Anaerobic Fixed-Bed and Sludge Blanket Bioreactors

by Sami Chatila and Marcelo Zaiat

Fermentation 2025, 11(9), 518; https://doi.org/10.3390/fermentation11090518 - 3 Sep 2025

Viewed by 1114

Abstract

Sugarcane vinasse, a byproduct of ethanol production, presents environmental challenges due to its high organic content and occasional contamination with antibiotics, such as monensin. This study successfully evaluated thermophilic two-phase anaerobic digestion for simultaneous monensin degradation and biogas production. The system, consisting of [...] Read more.

Sugarcane vinasse, a byproduct of ethanol production, presents environmental challenges due to its high organic content and occasional contamination with antibiotics, such as monensin. This study successfully evaluated thermophilic two-phase anaerobic digestion for simultaneous monensin degradation and biogas production. The system, consisting of an acidogenic anaerobic structured-bed bioreactor (ASTBR) operating at with a hydraulic retention time (HRT) of 7.5 h followed by a methanogenic reactor at HRT = 24 h, with two options of the methanogenic phase, an upflow anaerobic sludge blanket (UASB), and an ASTBR, operated continuously for 254 days with incremental monensin concentrations (0–2000 ng·mL⁻¹). The acidogenic reactor consistently removed over 70% of monensin across all phases, demonstrating its effectiveness as a pretreatment step. At realistic residual concentrations (20–100 ng·mL⁻¹), monensin not only failed to inhibit biogas production but enhanced methane yield by up to 100% through selective pressure on the microbial community. This study demonstrated that anaerobic digestion can effectively degrade monensin while increasing the value of vinasse, providing a scalable solution for mitigating antibiotic contamination and enhancing bioenergy recovery in the sugarcane–ethanol industry. Full article

(This article belongs to the Section Industrial Fermentation)

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Fermentation, Volume 11, Issue 9 (September 2025) – 59 articles

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