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Fermentation, Volume 11, Issue 1 (January 2025) – 44 articles

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15 pages, 1323 KiB  
Article
Functional Kimchi Beverage Enhanced with γ-Aminobutyric Acid (GABA) Through Serial Co-Fermentation Using Leuconostoc citreum S5 and Lactiplantibacillus plantarum KS2020
by Min-Jeong Kwon, Ji-Eun Kim and Sam-Pin Lee
Fermentation 2025, 11(1), 44; https://doi.org/10.3390/fermentation11010044 - 19 Jan 2025
Viewed by 758
Abstract
A plant-based beverage enhanced with GABA was developed through serial co-fermentation using Leuconostoc citreum S5 and Lactiplantibacillus plantarum KS2020. The first lactic acid fermentation was performed by Leu. citreum S5 with a vegetable mixture consisting of sliced radish, ginger, garlic, red pepper, bell [...] Read more.
A plant-based beverage enhanced with GABA was developed through serial co-fermentation using Leuconostoc citreum S5 and Lactiplantibacillus plantarum KS2020. The first lactic acid fermentation was performed by Leu. citreum S5 with a vegetable mixture consisting of sliced radish, ginger, garlic, red pepper, bell pepper, and sucrose. The viable cell count of Leu. citreum S5 increased to 9.11–9.42 log CFU/mL with higher sucrose contents, indicating the highest value of 9.42 log CFU/mL at 5% sucrose on day 1. Mannitol and dextran production levels in the first fermented vegetable mixture were 6.66–14.54 mg/mL and 0.44–2.26%, respectively. A higher sucrose content produced more dextran, resulting in a concomitant increase in viscosity of 49.4 mPa·s. The second co-fermentation for the kimchi beverage base was performed by Lb. plantarum KS2020 for 5 days, resulting in 8.22–9.60 log CFU/mL. The pH of the co-fermented kimchi beverage base increased to 6.19–9.57 with an increasing monosodium glutamate (MSG) content (3–7%), while titratable acidity significantly decreased to 0.0–0.8%. The final co-fermented kimchi beverage base was enriched with 2.6% GABA. Consequently, a GABA kimchi beverage base with probiotics, a red pigment, and a pleasant flavor was developed using only vegetable ingredients by serial co-fermentation using lactic acid bacteria. Full article
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21 pages, 7409 KiB  
Article
Harnessing the Influence of Pressure and Nutrients on Biological CO2 Methanation Using Response Surface Methodology and Artificial Neural Network—Genetic Algorithm Approaches
by Alexandros Chatzis, Konstantinos N. Kontogiannopoulos, Nikolaos Dimitrakakis, Anastasios Zouboulis and Panagiotis G. Kougias
Fermentation 2025, 11(1), 43; https://doi.org/10.3390/fermentation11010043 - 18 Jan 2025
Viewed by 797
Abstract
The biological methanation process has emerged as a promising alternative to thermo-catalytic methods due to its ability to operate under milder conditions. However, challenges such as low hydrogen solubility and the need for precise trace element supplementation (Fe(II), Ni(II), Co(II)) constrain methane production [...] Read more.
The biological methanation process has emerged as a promising alternative to thermo-catalytic methods due to its ability to operate under milder conditions. However, challenges such as low hydrogen solubility and the need for precise trace element supplementation (Fe(II), Ni(II), Co(II)) constrain methane production yield. This study investigates the combined effects of trace element concentrations and applied pressure on biological methanation, addressing their synergistic interactions. Using a face-centered composite design, batch mode experiments were conducted to optimize methane production. Response Surface Methodology (RSM) and Artificial Neural Network (ANN)—Genetic Algorithm (GA) approaches were employed to model and optimize the process. RSM identified optimal ranges for trace elements and pressure, while ANN-GA demonstrated superior predictive accuracy, capturing nonlinear relationships with a high R² (>0.99) and minimal prediction errors. ANN-GA optimization indicated 97.9% methane production efficiency with a reduced conversion time of 15.9 h under conditions of 1.5 bar pressure and trace metal concentrations of 25.0 mg/L Fe(II), 0.20 mg/L Ni(II), and 0.02 mg/L Co(II). Validation experiments confirmed these predictions with deviations below 5%, underscoring the robustness of the models. The results highlight the synergistic effects of pressure and trace metals in enhancing gas–liquid mass transfer and enzymatic pathways, demonstrating the potential of computational modeling and experimental validation to optimize biological methanation systems, contributing to sustainable methane production. Full article
(This article belongs to the Special Issue Microbial Fixation of CO2 to Fuels and Chemicals)
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14 pages, 683 KiB  
Article
Production of an Extract with β-1,4-Xylanase Activity by Fusarium oxysporum f. sp. melonis on a Sonicated Brewer’s Spent Grain Substrate
by Irma A. Arreola-Cruz, Rosalba Troncoso-Rojas, Francisco Vásquez-Lara, Nina G. Heredia-Sandoval and Alma R. Islas-Rubio
Fermentation 2025, 11(1), 42; https://doi.org/10.3390/fermentation11010042 - 18 Jan 2025
Viewed by 744
Abstract
The Fusarium oxysporum species commonly found in soil include plant and human pathogens, and nonpathogenic species. F. oxysporum grown on lignocellulosic substrates under submerged conditions produces an extracellular enzyme profile with hemicellulolytic and cellulolytic activities. Our aim was to produce an extract of [...] Read more.
The Fusarium oxysporum species commonly found in soil include plant and human pathogens, and nonpathogenic species. F. oxysporum grown on lignocellulosic substrates under submerged conditions produces an extracellular enzyme profile with hemicellulolytic and cellulolytic activities. Our aim was to produce an extract of Fusarium oxysporum f. sp. melonis with β-1,4-xylanase activity after fermentation on a Brewers’ spent grain (BSG)-containing substrate. We prepared the BSG substrate, with or without sonication, for the submerged fermentation of Fusarium oxysporum previously isolated from local soil and preserved at 4 °C. First, an enriched inoculum was prepared, and later, the production of β-1,4-xylanase using the BSG substrates was monitored for up to 6 or 10 days in the enriched inoculum or in the enzyme extract, respectively. An activity of β-1,4-xylanase 12.0 U/mL (day 3) was obtained in the enriched inoculum with the untreated BSG, remaining constant for 3 days. A significant increase in the activity of this enzyme was observed (day 6), especially in the extract obtained using the sonicated BSG substrate (39 U/mL). Applying ultrasound to the BSG before its use in a submerged fermentation with Fusarium oxysporum f. sp. melonis could be an alternative for producing β-1,4-xylanase. Full article
(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)
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18 pages, 1879 KiB  
Article
Batch Reactor Design and Conception at Laboratory Scale for Solid-State Anaerobic Digestion: Practical Comparison Between 3D-Printed Digesters and Conventional Methods
by Arnaud Dujany, Franco Otaola, Laura André, Amar Naji, Denis Luart, Mikel Leturia, André Pauss and Thierry Ribeiro
Fermentation 2025, 11(1), 41; https://doi.org/10.3390/fermentation11010041 - 18 Jan 2025
Viewed by 571
Abstract
Solid-state anaerobic digestion (SS-AD) is a promising technology for treating organic waste and producing renewable energy. This study explores the feasibility of using 3D printing to rapidly design cost-effective laboratory-scale digesters for optimization experiments. Batch reactors were designed using fused deposition modeling (FDM) [...] Read more.
Solid-state anaerobic digestion (SS-AD) is a promising technology for treating organic waste and producing renewable energy. This study explores the feasibility of using 3D printing to rapidly design cost-effective laboratory-scale digesters for optimization experiments. Batch reactors were designed using fused deposition modeling (FDM) with polylactic acid (PLA) and stereolithography (SLA) with High Temp V2 resin. PLA had a negligible impact on methane yields, while raw SLA resin positively influenced methanogenic potential, likely due to residual isopropanol used in post-processing, causing a 19% increase in CH4 yield. The performance of the 3D-printed reactors was compared to that of a conventionally machined PMMA reactor using cattle manure as a substrate, showing comparable methane yields and process stability. Three-dimensional printing technologies have demonstrated remarkable efficiency in designing laboratory-scale digesters, with a 70% cost reduction for SLA technology and an 80% reduction in design time compared to conventional reactors designed by plastics processing, while maintaining comparable biogas production. FDM technologies with PLA have shown that they are not suitable for these uses. This study demonstrates the potential of additive manufacturing to accelerate SS-AD research and development. However, care must be taken in material selection and post-processing to avoid introducing experimental bias. Full article
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18 pages, 4037 KiB  
Article
Bioenergetic Modeling of the Relationship Between Voltage and Electroactive Microbial Biomass Yield for Bioelectrochemical Carbon Dioxide Reduction to Methane
by Vafa Ahmadi and Nabin Aryal
Fermentation 2025, 11(1), 40; https://doi.org/10.3390/fermentation11010040 - 17 Jan 2025
Viewed by 494
Abstract
Optimal product synthesis in bioelectrochemical systems (BESs) requires a comprehensive understanding of the relationship between external voltage and microbial yield. While most studies assume constant growth yields or rely on empirical estimates, this study presents a novel thermodynamic model, linking anodic oxidation and [...] Read more.
Optimal product synthesis in bioelectrochemical systems (BESs) requires a comprehensive understanding of the relationship between external voltage and microbial yield. While most studies assume constant growth yields or rely on empirical estimates, this study presents a novel thermodynamic model, linking anodic oxidation and cathodic carbon dioxide (CO2) reduction to methane (CH4) by growing microbial biofilm. Through integrating theoretical Gibbs free energy calculations, the model predicts electron and proton transfers for autotrophic methanogen and anode-respiring bacteria (ARB) growth, accounting for varying applied voltages and substrate concentrations. The findings identify an optimal applied cathodic potential of −0.3 V vs. the standard hydrogen electrode (SHE) for maximizing CH4 production under standard conditions (pH 7, 25 °C, 1 atm) regardless of ohmic losses. The model bridges the stoichiometry of anodic and cathodic biofilms, addressing research gaps in simulating anodic and cathodic biofilm growth simultaneously. Additionally, sensitivity analyses reveal that lower substrate concentrations require more negative voltages than standard condition to stimulate microbial growth. The model was validated using experimental data, demonstrating reasonable predictions of biomass growth and CH4 yield under different operating voltages in a multi substrate system. The results show that higher voltage inputs increase biomass yield while reducing CH4 output due to non-optimal voltage. This validated model provides a tool for optimizing BES performance to enhance CH4 recovery and biofilm stability. These insights contribute to finding optimum voltage for the highest CH4 production for energy efficient CO2 reduction for scaling up BES technology. Full article
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17 pages, 3627 KiB  
Article
Isolation, Purification and In Vitro Characterization of a Newly Isolated Alkalophilic Phytase Produced by the Halophile Cobetia marina Strain 439 for Use as Animal Food Supplement
by Ivanka Boyadzhieva, Kaloyan Berberov, Nikolina Atanasova, Nikolay Krumov and Lyudmila Kabaivanova
Fermentation 2025, 11(1), 39; https://doi.org/10.3390/fermentation11010039 - 17 Jan 2025
Viewed by 661
Abstract
Economic development increases and brings about issues such as the secure supply of food in a sustainable way. Phytases are enzymes catalyzing phytate hydrolysis to release phosphorus in an inorganic form. Animal feeds could be supplemented with bacterial phytases to increase their phosphorus [...] Read more.
Economic development increases and brings about issues such as the secure supply of food in a sustainable way. Phytases are enzymes catalyzing phytate hydrolysis to release phosphorus in an inorganic form. Animal feeds could be supplemented with bacterial phytases to increase their phosphorus and micronutrients bioavailability. To the best of our knowledge, this is the first report on the purification and characterization of an alkalophilic phytase from Cobetia marina. The purified newly isolated phytase from the halophilic Cobetia marina strain 439 appears to be appropriate for use as an additive in food and feed processing. Its molecular weight was determined to be 43 kDa by gel filtration and 40 kDa by SDS–polyacrylamide gel electrophoresis. The purified enzyme had maximum activity at pH 8.0 and 45 °C, while at 70 °C, it was 80% and about 50% at 80 °C for 40 min, showing its thermostability. Enzyme activity was retained at a broad pH range from 6.5 to 9.0. The half-life of the phytase of 15 min at pH 10 and 30 min at pH 4.0 was registered. The enzyme was proven to be with high substrate specificity. In addition, the purified phytase showed strong proteolytic tolerance against trypsin and pepsin. The pH profile, its thermostability, and proteolytic tolerance of the studied phytase as a halophilic bacterial product determine it as a unique candidate for application in agriculture, food, and feed industries. Full article
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18 pages, 3410 KiB  
Article
Isolation and Characterization of Indigenous Acetobacter Strains from Cashew Apple and Their Potential Use in Vinegar Production
by Yaya Anianhou Ouattara, Doudjo Soro, Kouakou Romain Fossou, Ahou Cinthia Ines Yebouet, Ismael Abraham Cissé, Dogbo Marius Akissi, Adolphe Zézé, Emmanuel Assidjo and Kouassi Benjamin Yao
Fermentation 2025, 11(1), 38; https://doi.org/10.3390/fermentation11010038 - 17 Jan 2025
Viewed by 698
Abstract
Côte d’Ivoire has the largest cashew tree cultivation area in the world, but the cashew apple produced is still underutilized despite its potential for industrial use. The present study aimed to isolate and identify acetic acid bacterial strains and assess their potential use [...] Read more.
Côte d’Ivoire has the largest cashew tree cultivation area in the world, but the cashew apple produced is still underutilized despite its potential for industrial use. The present study aimed to isolate and identify acetic acid bacterial strains and assess their potential use for cashew apple-based vinegar production. Vinegar mother from fermented juice was used to isolate acetic acid bacteria on a standard glucose-based medium. Physiological and biochemical tests followed by 16S rRNA gene analysis and phylogeny were used for isolate characterization. Moreover, their acetic acid production capacity was assessed. As results, five strains of the Acetobacter genus were isolated. Phenotypic and phylogenetic analysis revealed that four of them, namely OYA2, OYA6, OYA9, and OYA10, belong to the A. tropicalis/A. senegalensis species complex with 99.7% or 100% similarity. The fifth strain, OYA7, being similar (99.7%) to A. syzygii. All the isolates were resistant to alcohol 15% (v/v) and grew well between pH 5.0 and 6.5. Their optimal growth temperatures varied between 27 °C and 37 °C, and only isolate OYA6 grew at a temperature of up to 40 °C. They produced vinegar with a yield (Yp/s, g/g) varying from 0.82 to 0.92, and acetic acid contents (g/L) of 80.67, 70.26, 70.11, 68.70 and 67.22 were obtained with OYA6, OYA7, OYA2, OYA10, and OYA9, respectively. Thus, the isolate OYA6 appeared as the best candidate for vinegar production, owing to its superior yield and thermotolerance abilities that need to be further explored for industry use. Full article
(This article belongs to the Section Fermentation for Food and Beverages)
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27 pages, 2817 KiB  
Article
A Novel Wild-Type Lacticaseibacillus paracasei Strain Suitable for the Production of Functional Yoghurt and Ayran Products
by Ioanna Prapa, Chrysoula Pavlatou, Vasiliki Kompoura, Anastasios Nikolaou, Electra Stylianopoulou, George Skavdis, Maria E. Grigoriou and Yiannis Kourkoutas
Fermentation 2025, 11(1), 37; https://doi.org/10.3390/fermentation11010037 - 17 Jan 2025
Viewed by 711
Abstract
Raw goat and ewe’s milk samples were used for the isolation of seven lactic acid bacteria new strains. After testing hemolytic activity and resistance to antibiotics, specific functional properties were evaluated; Lactococcus lactis subsp. lactis FBM_1321 and Lacticaseibacillus paracasei FBM_1327 strains resulted in [...] Read more.
Raw goat and ewe’s milk samples were used for the isolation of seven lactic acid bacteria new strains. After testing hemolytic activity and resistance to antibiotics, specific functional properties were evaluated; Lactococcus lactis subsp. lactis FBM_1321 and Lacticaseibacillus paracasei FBM_1327 strains resulted in the highest cholesterol assimilation percentages ranging from 28.78 to 30.56%. In addition, strong adhesion capacity to differentiated Caco-2 cells (1.77–21.04%) was mapped, and the lactobacilli strains exhibited strong antagonistic activity against foodborne pathogens compared to lactococci. The strains were able to grow at low pH and high NaCl concentrations, conditions that prevail in food systems (cell counts ranged from 1.77 to 8.48 log CFU/mL after exposure to pH 3 and from 5.66 to 9.52 log CFU/mL after exposure to NaCl concentrations up to 8%). As a next step, freeze-dried immobilized Lc. paracasei FBM_1327 cells on oat flakes were used for the preparation of functional yoghurt and ayran products. Cell loads of the functional strain remained high and stable in both products (7.69 log CFU/g in yoghurt and 8.56 log CFU/g in ayran after 30 days of storage at 4 °C) throughout their shelf life. No significant changes in the volatile profile were noticed, and the new products were accepted by the panel during the sensory evaluation. Full article
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25 pages, 2232 KiB  
Review
Antimicrobial Peptides, Their Production, and Potential in the Fight Against Antibiotic-Resistant Pathogens
by Margarita Saubenova, Alexander Rapoport, Zhanerke Yermekbay and Yelena Oleinikova
Fermentation 2025, 11(1), 36; https://doi.org/10.3390/fermentation11010036 - 17 Jan 2025
Viewed by 872
Abstract
The article reviews the literature on antimicrobial peptides (AMPs) that exhibit unique antimicrobial mechanisms, such as broad-spectrum activity, low development of antimicrobial resistance, and the ability to modulate the immune response of the host organism. Information is provided on the significant potential of [...] Read more.
The article reviews the literature on antimicrobial peptides (AMPs) that exhibit unique antimicrobial mechanisms, such as broad-spectrum activity, low development of antimicrobial resistance, and the ability to modulate the immune response of the host organism. Information is provided on the significant potential of AMPs in the fight against pathogens threatening human health and food safety. Enrichment of the human diet with biologically active peptides obtained using the proteolytic activity of lactic acid bacteria (LAB) is proposed as a simple, accessible, and viable alternative to antibiotics that does not have a harmful side effect. The review briefly covers the methods for obtaining AMPs and features of the LAB proteolytic system responsible for producing bioactive peptides in the environment. It has been shown that using various LAB strains makes it possible to produce high-quality whey-based beverages with different directions of antagonistic activity against opportunistic pathogens and helps optimize the gastrointestinal microbiota. It is assumed that such drinks can reduce the dose of antimicrobials in the combined therapy of various infectious diseases and be a preventive measure against contagion and the spread of antimicrobial resistance. Full article
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11 pages, 560 KiB  
Article
Impact of Commercial Protective Culture on Manouri PDO Cheese
by Thomas Bintsis and Maria A. Kyritsi
Fermentation 2025, 11(1), 35; https://doi.org/10.3390/fermentation11010035 - 16 Jan 2025
Viewed by 495
Abstract
Manouri is a Greek whey cheese, with a Protected Denomination of Origin recognition, produced by heating the cheese whey and added milk and/or cream at high temperatures (88–90 °C) to form a coagulum. High-heat treatment results in the inactivation of any indigenous microorganisms [...] Read more.
Manouri is a Greek whey cheese, with a Protected Denomination of Origin recognition, produced by heating the cheese whey and added milk and/or cream at high temperatures (88–90 °C) to form a coagulum. High-heat treatment results in the inactivation of any indigenous microorganisms from the raw materials. However, the high moisture, fat and pH of the cheese make it a favorable medium for the growth of any microbial contamination. The objective of this study was to investigate the application of a commercial protective culture (CPC) on the microbial profile of Manouri cheese during storage. Three treatments were prepared: S1 was the control cheese with sterile water sprayed on the surface, S2 was sprayed with a dense CPC and S3 with a diluted CPC. The experimental cheeses were covered with greaseproof paper and stored at 5 °C for 21 days. For all three treatments, the fat content and total solids showed a significant increase during storage, while protein and carbohydrates showed a significant decrease at 14 days. The application of the CPC resulted in cheeses with higher pH than the control cheese, probably due to the growth of acidifying lactic acid bacteria in the microbiota of the S2 and S3 cheeses. Manouri cheese sprayed with the CPC showed a reduction of 1.60–1.69 log CFU/g in the population of yeasts; no effect was observed on Enterobacteriaceae and Staphylococcus spp. The dominant yeast microbiota was identified as Candida zeylanoides (63.5%), Candida parapsilosis (21.1%) and Candida famata (15.4%). Although the application of the CPC was not able to control the spoilage bacteria, it showed an effective way to control the growth of yeasts in Manouri cheese. However, the presence of certain Candida spp. reveals the significance of applying good hygiene practices throughout the cheesemaking process. Full article
(This article belongs to the Special Issue Dairy Fermentation, 3rd Edition)
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12 pages, 2290 KiB  
Article
Heterologous Expression and Functional Analysis of Exiguobacterium Algin Lyase Gene by Pichia pastoris
by Hanwen Wu, Kai Hou, Yutong Jiang, Mingjian Luan, Yuxia Sun, Xi He and Xiangzhong Zhao
Fermentation 2025, 11(1), 34; https://doi.org/10.3390/fermentation11010034 - 16 Jan 2025
Viewed by 507
Abstract
Algin is the most abundant substance in alga. Alginate lyase degrades algin and produces algin monosaccharides, disaccharides, and oligosaccharides, which are widely used in bioenergy, food, medicine, and other fields. In this study, one Exiguobacterium strain isolated from rotten kelp exhibited a robust [...] Read more.
Algin is the most abundant substance in alga. Alginate lyase degrades algin and produces algin monosaccharides, disaccharides, and oligosaccharides, which are widely used in bioenergy, food, medicine, and other fields. In this study, one Exiguobacterium strain isolated from rotten kelp exhibited a robust ability to degrade the alga. The sequencing of this strain revealed the presence of three different types of algin alginate lyase. Nevertheless, the expression of three genes in Escherichia coli revealed a lower alginate lyase activity compared to that of the original strain. After codon optimization, the gene with the highest activity of the three was successfully expressed in Pichia pastoris to produce recombinant EbAlg664. The activity of the recombinant enzyme in 5 L high-density fermentation reached 1306 U/mg protein, 3.9 times that of the original Exiguobacterium strain. The results of the enzymatic analysis revealed that the optimal temperature and the pH range of recombinant EbAlg664 were narrower compared to the original strain. Additionally, the presence of Cu2+ and Co2+ enhanced the enzymatic activity, whereas Mg2+ and Fe3+ exhibited inhibitory effects on the recombinant alginate lyase. The study offers a theoretical and practical foundation for the industrial-scale production of engineered Pichia pastoris with high alginate lyase activity. Full article
(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)
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18 pages, 1334 KiB  
Article
The Production of an Economical Culture Medium from Apple Pomace for the Propagation of Non-Conventional Cidermaking Yeast Starters
by Josefina M. Fontanini, Andrea C. Origone, Marcela P. Sangorrín, Carmen R. Maturano, Christian A. Lopes and M. Eugenia Rodríguez
Fermentation 2025, 11(1), 33; https://doi.org/10.3390/fermentation11010033 - 15 Jan 2025
Viewed by 627
Abstract
The aim of the present study was to evaluate the use of different chemical treatments of apple pomace in order to produce an economical culture medium for the propagation of two non-conventional yeast strains. An experimental design approach was used for the optimization [...] Read more.
The aim of the present study was to evaluate the use of different chemical treatments of apple pomace in order to produce an economical culture medium for the propagation of two non-conventional yeast strains. An experimental design approach was used for the optimization of the hydrolysis conditions of apple pomace. Both acid and alkaline treatment conditions were tested. The optimal hydrolysis conditions to disrupt the pomace lignocellulosic structure were 1% w/v of H3PO4, 121 °C, and 40 min for acid treatment, while 6% w/v of NH4OH, 20 °C, and 2 h were optimal for the alkaline condition. Saccharomyces uvarum NPCC 1420 and Saccharomyces eubayanus NPCC 1292 yeasts were able to grow in the liquid fraction obtained from both acid and alkaline treatments. However, the medium with the acid treatment was found to be more suitable for yeast growth, showing, for both strains, higher µmax and biomass production and lower td and λ than that observed for the medium with the alkaline treatment. According to the growth parameter analysis for both strains, the acid treatment was selected for further studies. By taking advantage of this agroindustrial by-product, a circular economy approach is promoted, reducing environmental impact and fostering sustainable development. Full article
(This article belongs to the Special Issue Waste as Feedstock for Fermentation)
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11 pages, 1570 KiB  
Article
Enhancing Bioactive Cordycepin Production via Precision Fermentation with an Engineered Aspergillus oryzae
by Jutamas Anantayanon, Warinthon Chamkhuy, Nakul Rattanaphan, Sarocha Panchanawaporn, Kobkul Laoteng and Sukanya Jeennor
Fermentation 2025, 11(1), 32; https://doi.org/10.3390/fermentation11010032 - 15 Jan 2025
Viewed by 538
Abstract
An optimal culture medium and highly stable biometabolites are important in industrial production processes. The response surface methodology with a Box–Behnken design was performed to determine the optimal culture medium of an engineered Aspergillus oryzae strain for cordycepin production by submerged fermentation. The [...] Read more.
An optimal culture medium and highly stable biometabolites are important in industrial production processes. The response surface methodology with a Box–Behnken design was performed to determine the optimal culture medium of an engineered Aspergillus oryzae strain for cordycepin production by submerged fermentation. The influences of glucose, yeast extract, and adenine concentrations on cordycepin production were explored, and their concentrations were used for experimental design. The results reveal that the optimal culture components involved 30.0 g/L of glucose, 9.8 g/L of yeast extract, and 1.5 g/L of adenine. As predicted, the maximum cordycepin concentration (1724.53 ± 18.30 mg/L) was obtained with a short fermentation time (2 days). A significant increase in cordycepin yield (>50% increase) was observed in the culture grown in the optimized culture medium compared to that grown in the basal medium. A xanthine oxidase inhibitory activity assay demonstrated that the cordycepin product had a pharmacological function. It exhibited strong stability under high thermal and acidic conditions, with over 95% product recovery. The findings of this study are valuable for developing cost-effective processes for producing health-benefiting products. Full article
(This article belongs to the Special Issue New Research on Fungal Secondary Metabolites, 2nd Edition)
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18 pages, 2454 KiB  
Article
Carbon Dioxide Micro-Nano Bubbles Aeration Improves Carbon Fixation Efficiency for Succinic Acid Synthesis by Escherichia coli
by Ying Chen, Hao Wu, Qianqian Huang, Jingwen Liao, Liuqing Wang, Yue Pan, Anming Xu, Wenming Zhang and Min Jiang
Fermentation 2025, 11(1), 31; https://doi.org/10.3390/fermentation11010031 - 14 Jan 2025
Viewed by 644
Abstract
The low solubility of CO2 in water leads to massive CO2 emission and extremely low CO2 utilization in succinic acid (SA) biosynthesis. To enhance microbial CO2 utilization, micro-nano bubbles (MNBs) were induced in SA biosynthesis by E. coli Suc260 [...] Read more.
The low solubility of CO2 in water leads to massive CO2 emission and extremely low CO2 utilization in succinic acid (SA) biosynthesis. To enhance microbial CO2 utilization, micro-nano bubbles (MNBs) were induced in SA biosynthesis by E. coli Suc260 in this study. The results showed that MNB aeration decreased CO2 emissions and increased CO2 solubility in the medium significantly. The CO2 utilization of MNB aeration was 129.69% higher than that of bubble aeration in atmospheric fermentation. However, MNBs showed a significant inhibitory effect on bacterial growth in the pressurized environment, although a two-stage aerobic–anaerobic fermentation strategy weakened the inhibition. The biofilm-enhanced strain E. coli Suc260-CsgA showed a strong tolerance to MNBs. In pressurized fermentation with MNB aeration, the actual CO2 utilization of E. coli Suc260-CsgA was 30.63% at 0.18 MPa, which was a 6.49-times improvement. The CO2 requirement for SA synthesis decreased by 83.4%, and the fugitive emission of CO2 was successfully controlled. The activities of key enzymes within the SA synthesis pathway were also maintained or enhanced in the fermentation process with MNB aeration. These results indicated that the biofilm-enhanced strain and CO2-MNBs could improve carbon fixation efficiency in microbial carbon sequestration. Full article
(This article belongs to the Section Fermentation Process Design)
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13 pages, 1269 KiB  
Article
Co-Cultivations of Beauveria bassiana, Metarhizium anisopliae, and Trichoderma harzianum to Produce Bioactive Compounds for Application in Agriculture
by Pauline Flores da Silva, Maicon Sérgio Nascimento dos Santos, Beatriz de Andrade Araújo, Bruno Douglas Kerber, Heloisa Alves Pinto de Oliveira, Jerson Vanderlei Carús Guedes, Marcio Antonio Mazutti, Marcus Vinícius Tres and Giovani Leone Zabot
Fermentation 2025, 11(1), 30; https://doi.org/10.3390/fermentation11010030 - 14 Jan 2025
Viewed by 590
Abstract
Regenerative agriculture aims to improve soil quality and restore soil biodiversity, re-establishing natural systems in agricultural areas. Among some strategies, it is important to reduce the use of chemical pesticides that affect the productive capacity of the soil and cause problems to the [...] Read more.
Regenerative agriculture aims to improve soil quality and restore soil biodiversity, re-establishing natural systems in agricultural areas. Among some strategies, it is important to reduce the use of chemical pesticides that affect the productive capacity of the soil and cause problems to the environment. Based on this necessity, we present a strategy of producing a single product with bioinsecticidal and biofungicidal effects by submerged co-cultivations and paired cultivations of Beauveria bassiana, Metarhizium anisopliae, and Trichoderma harzianum using different concentrations of glucose, sucrose, hydrolyzed animal protein (HAP), soybean meal hydrolysate plus organic phosphorus (SMH), and hydrolyzed feathers (HF) as renewable nutrients. The single cultivations and double and triple co-cultivations were carried out for 7 days at 28 °C in orbital agitation at 120 rpm. Most of the highest values of conidia were obtained in the treatments at the central point, in which (g L−1) glucose (20), sucrose (10), HAP (7.5), SMH (2.5), and HF (2.5) were used. The fermented broths were applied to the backs of adult bugs (Euschistus heros), which mostly provided 66–88% mortality. Beauveria bassiana + Metarhizium anisopliae showed approximately 70% inhibition against Sclerotinia sclerotiorum and Macrophomina phaseolina. As a way forward, this product demonstrated integrated bioactivities as insecticide and fungicide and can be optimized to substitute chemical pesticides that have negative impacts on the environment. Full article
(This article belongs to the Special Issue Metabolic Engineering in Microbial Synthesis)
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17 pages, 4281 KiB  
Article
Optimizing Bacterial Protectant Composition to Enhance Baijiu Yeast Survival and Productivity During Spray Drying
by Jingyu Li, Fengkui Xiong, Zhongbin Liu, Jia Zheng, Guangzhong Hu and Zheng Feng
Fermentation 2025, 11(1), 29; https://doi.org/10.3390/fermentation11010029 - 13 Jan 2025
Viewed by 508
Abstract
The flavor substances produced by the division of baijiu yeast during the winemaking process often determine the quality of white wine, and the difficulty of storing and transporting high-quality baijiu yeast is a bottleneck that restricts the development of China’s baijiu industry. It [...] Read more.
The flavor substances produced by the division of baijiu yeast during the winemaking process often determine the quality of white wine, and the difficulty of storing and transporting high-quality baijiu yeast is a bottleneck that restricts the development of China’s baijiu industry. It is widely accepted that drying microorganisms such as baijiu yeast is the best way to improve its storage and transport performance. Spray drying, as one of the most widely used microbial drying processes, with a high efficiency and low cost, is the hot spot of current research in the field of microbial drying, but it has the inherent defect of a low drying survival rate. In order to address this inherent defect, the present study was carried out with a high-quality white wine yeast, Modified Sporidiobolus Johnsonii A (MSJA), as the target. Firstly, an orthogonal experiment, Steep Hill Climbing experiment, and response surface experiment were sequentially designed to optimize the type and amount of protective agent added in the spray-drying process of MSJA. Then, the effects of glutamyl transaminase (TGase) treatment on the drying process of MSJA were revealed with the help of advanced equipment, such as laser particle sizer, environmental scanning electron microscope (ESEM), and Fourier-transform infrared scanner (FTIR). The results showed that the addition of “TGase-treated soybean isolate protein (SPI) + lactic protein (LP)” as an in vitro bacterial protectant and “14.15% trehalose + 7.10% maltose + 14.04% sucrose” TGase treatment can promote the cross-linking of protective proteins, reduce the distance between MSJA bacteria and protective proteins, and increase the glass transition temperature to enhance the protective effect of protective proteins, so as to improve the survival rate of MSJA during spray drying. Full article
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17 pages, 923 KiB  
Article
Preliminary Study on the Impact of Ruminal Ciliate Inoculation in Fauna-Free Conditions on the Ruminal Fermentation and Ciliate–Prokaryote Association In Vitro
by Geonwoo Kim, Woohyung Lee and Tansol Park
Fermentation 2025, 11(1), 28; https://doi.org/10.3390/fermentation11010028 - 11 Jan 2025
Viewed by 420
Abstract
Ruminants rely on the rumen for the anaerobic fermentation of fibrous plant materials, facilitated by a complex microbial community of bacteria, archaea, fungi, and ciliates. Among them, ruminal ciliates significantly influence ruminal fermentation, methane production, nitrogen utilization efficiency, and microbial interactions. This study [...] Read more.
Ruminants rely on the rumen for the anaerobic fermentation of fibrous plant materials, facilitated by a complex microbial community of bacteria, archaea, fungi, and ciliates. Among them, ruminal ciliates significantly influence ruminal fermentation, methane production, nitrogen utilization efficiency, and microbial interactions. This study examined the impact of ciliate inoculation on ruminal fermentation, microbial composition, and functional profiles in fauna-free conditions. Six treatments were tested: control (no ciliates), small entodinia, Epidinium spp., isotrichids, Ophryoscolex spp., and a mixed inoculum. Using QIIME2 to analyze 16S rRNA gene sequences, the study revealed group-specific effects on methane production, volatile fatty acids (VFAs), and microbial diversity. Small entodinia inoculation increased Streptococcus abundance, while isotrichids enriched Megasphaera, enhancing butyrate production. Alpha diversity indices indicated reduced richness in the ciliate-inoculated groups, reflecting predation on prokaryotes. Beta diversity showed distinct microbial and functional profiles among the treatments. Functional analysis highlighted elevated glycerolipid metabolism in isotrichid groups, associated with Bacteroides and Megasphaera, suggesting roles in lipid metabolism and oxidative stress resistance. Despite limited ciliate cell counts, the study emphasizes ciliate-specific interactions and the role of lactic acid-associated bacteria in shaping ruminal fermentation. Full article
(This article belongs to the Special Issue Ruminal Fermentation)
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20 pages, 2098 KiB  
Article
The Impact of Grape Maceration on Quality and Biogenic Amine Formation in Slovak Tokaj Wines: Examination of Microbial, Chemical and Sensory Properties
by Boris Semjon, Martin Bartkovský, Peter Očenáš, Ivana Regecová, Zuzana Megyesy Eftimová, Jana Výrostková, Lýdia Mesarčová, Mariana Kováčová, Matúš Várady, Lucia Šuľáková and Slavomír Marcinčák
Fermentation 2025, 11(1), 27; https://doi.org/10.3390/fermentation11010027 - 10 Jan 2025
Viewed by 575
Abstract
Grape maceration is essential in modulating the quality of Tokaj wines. The aim of this research was to analyse the effect of two maceration practices—one utilizing the application of a Saccharomyces cerevisiae culture and the other being maceration without a yeast culture in [...] Read more.
Grape maceration is essential in modulating the quality of Tokaj wines. The aim of this research was to analyse the effect of two maceration practices—one utilizing the application of a Saccharomyces cerevisiae culture and the other being maceration without a yeast culture in experimental Lipovina (Vitis vinifera L.) white wine from the Slovak part of the Tokaj region. Multiple factor analysis was used for the examination of wine quality regarding the formation of biogenic amines (BAs), and chemical, microbial and sensory variables were analysed over three months of wine production. The formation of bioactive components in wine was affected by maceration and maceration with the addition of a yeast culture, which resulted in a significantly increased antioxidant activity, as well as total phenolic and flavonoid content (p < 0.001). The wine samples that underwent maceration scored significantly lower in their appearance, aroma and taste (p < 0.05), which could be caused by a higher phenolic content and specific taste. The dynamics of BA formation in wine, evaluated using multiple factor analysis, highlighted that the maceration and maceration with an added yeast culture significantly affected these processes (p < 0.05). Microbiological examination promoted stable yeast counts during the maceration process, ensuring their longer presence during fermentation. Future research should aim to optimize maceration time in order to enhance the sensory quality of macerated wines without increasing the BA concentration, especially that of histamine. Full article
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14 pages, 1115 KiB  
Article
The Impact of Fermented Quinoa Sourdough with Enterococcus Strains on the Nutritional, Textural, and Sensorial Features of Gluten-Free Muffins
by Souraya Sakoui, Reda Derdak, Fatimazahra Jouga, Amal Dagni, Oana Lelia Pop, Dan Cristian Vodnar, Bernadette-Emőke Teleky, Maria Simona Chis, Carmen Rodica Pop, Laura Stan, Floricuta Ranga, Ramona Suharoschi, Abdelaziz Soukri and Bouchra El Khalfi
Fermentation 2025, 11(1), 26; https://doi.org/10.3390/fermentation11010026 - 9 Jan 2025
Viewed by 523
Abstract
Gluten-free baked goods exhibit reduced texture and taste characteristics compared to their gluten-containing counterparts. As a result, there is a renewed interest in the fermentation of gluten-free cereals with lactic acid bacteria, which is associated with an improvement in the final baked goods. [...] Read more.
Gluten-free baked goods exhibit reduced texture and taste characteristics compared to their gluten-containing counterparts. As a result, there is a renewed interest in the fermentation of gluten-free cereals with lactic acid bacteria, which is associated with an improvement in the final baked goods. Quinoa is garnering growing attention due to its different nutrients and bioactive substances, and it is notably employed to build gluten-free goods. In the present study, quinoa flour was fermented with Enterococcus strains (E. gallinarum SL2 and E. mundtii SL1), and further used in the manufacturing of gluten-free muffins. Several analyses were performed on the obtained sourdoughs and muffins, including a viscosity study, a textural and sensory analysis, and a polyphenol, organic acid, and carbohydrate content analysis. The results showed that the fermented quinoa flour exhibited enhanced nutritional value, with increased levels of organic acids such as lactic and acetic acid, as well as improved polyphenol content. The sensory and textural analyses revealed that both Enterococcus strains positively impacted the sensory characteristics and texture of the muffins. Notably, muffins prepared with E. mundtii SL1 demonstrated superior elasticity and overall taste. These results suggest that fermentation with these strains can significantly improve the nutritional profile and sensory quality of gluten-free baked goods, offering a promising approach for the development of healthier and more appealing gluten-free products. Full article
(This article belongs to the Section Fermentation for Food and Beverages)
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13 pages, 2030 KiB  
Article
High-Titer L-lactic Acid Production by Fed-Batch Simultaneous Saccharification and Fermentation of Steam-Exploded Corn Stover
by Liheng Deng, Changsheng Su, Yilu Wu, Qiang Xue, Changwei Zhang, Yong Wang, Bin Wang and Di Cai
Fermentation 2025, 11(1), 25; https://doi.org/10.3390/fermentation11010025 - 9 Jan 2025
Viewed by 528
Abstract
Steam explosion (SE) is an effective lignocellulose pretreatment technology for second-generation L-lactic acid (L-LA) production. In this study, targeted to produce high-concentration L-LA from corn stover (CS), the fed-batch simultaneous saccharification and fermentation (SSF) of acidic, SE-pretreated CS was developed and demonstrated in [...] Read more.
Steam explosion (SE) is an effective lignocellulose pretreatment technology for second-generation L-lactic acid (L-LA) production. In this study, targeted to produce high-concentration L-LA from corn stover (CS), the fed-batch simultaneous saccharification and fermentation (SSF) of acidic, SE-pretreated CS was developed and demonstrated in a 5 L scale bioreactor under non-strict conditions (without detoxification and sterilization). The results indicated that the fed-batch SSF, with a simple pH control, realized a higher tolerance of the strains to the toxic by-products of hydrolysate, in comparison to the conventional sequential hydrolysis and fermentation (SHF), allowing for 153.8 g L−1 of L-LA production, along with a productivity of 1.83 g L−1 h−1 in a system with a total of 40% (w/v) solid loading. The mass balance indicated that up to 449 kg of L-LA can be obtained from 1 t of dried CS. It exhibited obvious superiorities and laid down a solid foundation for the industrialization of second-generation L-LA production. Full article
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25 pages, 1232 KiB  
Review
Is It Possible to Produce Meat Without Animals? The Potential of Microorganisms as Protein Sources
by Alan Portal D’Almeida and Tiago Lima de Albuquerque
Fermentation 2025, 11(1), 24; https://doi.org/10.3390/fermentation11010024 - 9 Jan 2025
Viewed by 1166
Abstract
Climate change and environmental impacts from greenhouse gas emissions have spurred on efforts to reduce these emissions. Meat production, especially from cattle, is a significant contributor, releasing methane—a greenhouse gas far more potent than CO2—and driving deforestation for pastureland. As a [...] Read more.
Climate change and environmental impacts from greenhouse gas emissions have spurred on efforts to reduce these emissions. Meat production, especially from cattle, is a significant contributor, releasing methane—a greenhouse gas far more potent than CO2—and driving deforestation for pastureland. As a sustainable alternative, Single-Cell Protein (SCP), derived from microorganisms like bacteria, yeast, and algae, offers high nutritional value with a lower environmental impact. SCP production has advanced through process optimization, the use of eco-friendly substrates such as agro-industrial and food waste, and the cultivation of safe microorganisms classified as Generally Regarded as Safe (GRAS). Innovations in flavor and texture, including the use of myoglobin and natural polymers to mimic meat properties, have further improved SCP’s appeal. Despite these advances, challenges remain in optimizing production parameters, enhancing sensory acceptance, and ensuring regulatory compliance for market introduction. This review explores the potential of SCP to serve as a sustainable protein source, addressing both environmental concerns and nutritional demands. It highlights recent advancements in production techniques and sensory improvements while discussing their role in environmentally friendly and health-conscious food systems. SCP stands out as a promising solution for reducing greenhouse gas emissions, offering an efficient and sustainable alternative to conventional protein sources. Full article
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22 pages, 2307 KiB  
Review
Bacterial Cellulose: From Biofabrication to Applications in Sustainable Fashion and Vegan Leather
by Dheanda Absharina, Mohamad Padri, Csilla Veres and Csaba Vágvölgyi
Fermentation 2025, 11(1), 23; https://doi.org/10.3390/fermentation11010023 - 8 Jan 2025
Viewed by 1099
Abstract
The rising demand for sustainable materials has led to a significant focus on developing resources from renewable systems, particularly through the integration of biological processes. Bacterial cellulose (BC) has emerged as a highly promising biomaterial, gaining attention across multiple industries, such as food, [...] Read more.
The rising demand for sustainable materials has led to a significant focus on developing resources from renewable systems, particularly through the integration of biological processes. Bacterial cellulose (BC) has emerged as a highly promising biomaterial, gaining attention across multiple industries, such as food, pharmaceuticals, materials science, and textiles, due to its renewable, biodegradable, and eco-friendly characteristics. Within the fashion industry, bacterial cellulose (BC) biofabrication presents a groundbreaking method for producing sustainable textiles and vegan leather. This systematic review emphasizes BC’s pivotal role in advancing sustainable materials, addressing challenges like low yields, strain instability, and high production costs, and exploring innovative biofabrication techniques to overcome these barriers. Current advancements aim to enhance the thickness, uniformity, and mechanical properties of BC layers by optimizing the environmental and nutritional conditions during Komagataeibacter cultivation and leveraging coculturing methods. Furthermore, recent innovations in synthetic biology and genetic engineering have opened new avenues for improving BC biosynthesis, making it a viable solution for the sustainable fashion industry. This review explores three core topics: (1) bacterial cellulose and its applications, (2) the biofabrication of BC for vegan leather, and (3) emerging innovations and patents utilizing bacterial cellulose as a sustainable industrial biomaterial. Full article
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24 pages, 10488 KiB  
Article
Meta-Omics Analyses of Conventional and Regenerative Fermented Vegetables: Is There an Impact on Health-Boosting Potential?
by Kylene Guse, Qingqing Mao, Chi Chen and Andres Gomez
Fermentation 2025, 11(1), 22; https://doi.org/10.3390/fermentation11010022 - 7 Jan 2025
Viewed by 528
Abstract
Fermented vegetables contain probiotic microbes and metabolites, which are transformed from fresh vegetables, potentially providing health benefits. The kind of vegetable used to ferment and how it is grown may determine the types of health-promoting properties. To understand the possible benefits of fermented [...] Read more.
Fermented vegetables contain probiotic microbes and metabolites, which are transformed from fresh vegetables, potentially providing health benefits. The kind of vegetable used to ferment and how it is grown may determine the types of health-promoting properties. To understand the possible benefits of fermented vegetables under different growing conditions, we compared the microbiomes and metabolomes of three different types of naturally fermented vegetables—carrots, peppers, and radishes—that were grown either under conventional or regenerative growing systems. We profiled bacterial and fungal communities via 16S rRNA short-read (V4 region), long-read, and ITS2 sequencing, in tandem with untargeted metabolomics (LC-MS). The results showed that the microbiomes and metabolomes of the fermented vegetables under each growing system are unique, highlighting distinctions in amino acid content and potentially probiotic microbes (p < 0.05). All fermented vegetables contained high amounts of gamma-aminobutyric acid (GABA), a critical neurotransmitter. However, GABA was found to be in higher abundance in the regenerative fermented vegetables, particularly in carrots (p < 0.01) and peppers (p < 0.05), and was associated with higher abundances of the typically probiotic Lactiplantibacillus plantarum. Our findings indicate that the growing system may impact the microbiome and metabolome of plant-based ferments, encouraging more research on the health-boosting potential of regeneratively grown vegetables. Full article
(This article belongs to the Special Issue Advances in Fermented Fruits and Vegetables)
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20 pages, 3067 KiB  
Article
Development of a Gluten Standard from Relevant Sources of Wheat and Investigation into Gluten Content of Supplemental Enzymes Generated During Fermentation
by Pyeongsug Kim, Natasha Kim Leeuwendaal, Jonathon Niño Charari, Joan Colom, John Deaton and Kieran Rea
Fermentation 2025, 11(1), 21; https://doi.org/10.3390/fermentation11010021 - 7 Jan 2025
Viewed by 509
Abstract
During fermentation, bacterial and fungal species synthesize substrate-specific enzymes to obtain nutrients. During this process, potential allergenic products, including immunologically important gluten peptides, can be created. Current protocols for assessing the levels of these peptides often overlook the specific gluten source. In this [...] Read more.
During fermentation, bacterial and fungal species synthesize substrate-specific enzymes to obtain nutrients. During this process, potential allergenic products, including immunologically important gluten peptides, can be created. Current protocols for assessing the levels of these peptides often overlook the specific gluten source. In this study, wheat sources provided by commercial enzyme suppliers underwent gluten extraction before being pooled into a Complete Gluten Mix, which then underwent variations of hydrolysis utilizing the digestive enzymes, pepsin and trypsin complexes. The resulting gluten peptide profiles were examined using the Wes automated Western blot system to confirm the presence of small, immunologically relevant gluten peptides. These hydrolysates were further tested for suitability as a relevant calibrant against commercially available ELISA standards. The PT3 calibrant, a hydrolyzed version of the Complete Gluten Mix, was found to be the most suitable, as it contained <50 kDa gluten peptides and gave similar absorbance readings to the majority of ELISA kit standards tested, and overlaid the GlutenTox® Competitive G12 antibody calibration curve, which was designed against the 33-mer immunogenic peptide from wheat. Additionally, no gluten bands were observed on the Wes for the enzymes of interest, which was confirmed through ELISA analysis. Full article
(This article belongs to the Special Issue Bioactive Compounds in Grain Fermentation: 2nd Edition)
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24 pages, 2714 KiB  
Article
Pleurotus ostreatus: Nutritional Enhancement and Antioxidant Activity Improvement Through Cultivation on Spent Mushroom Substrate and Roots of Leafy Vegetables
by Eirini-Maria Melanouri, Ilias Diamantis, Marianna Dedousi, Eleni Dalaka, Paraskevi Antonopoulou, Seraphim Papanikolaou, Ioannis Politis, Georgios Theodorou and Panagiota Diamantopoulou
Fermentation 2025, 11(1), 20; https://doi.org/10.3390/fermentation11010020 - 7 Jan 2025
Viewed by 702
Abstract
Agricultural residues, including Pleurotus ostreatus spent mushroom substrate (SMS) and roots of (hydroponic) leafy vegetables (RLV), were tested in various proportions as substrates in new P. ostreatus cultivations, where wheat straw was the control. The impact of SMS and RLV was first evaluated [...] Read more.
Agricultural residues, including Pleurotus ostreatus spent mushroom substrate (SMS) and roots of (hydroponic) leafy vegetables (RLV), were tested in various proportions as substrates in new P. ostreatus cultivations, where wheat straw was the control. The impact of SMS and RLV was first evaluated by the mycelial growth rate (Kr, mm/day). Afterwards, mushroom cultivation was conducted in bags, where production characteristics like earliness (the time from substrate inoculation to first harvest) and biological efficiency (BE %, the ratio of fresh mushroom weight to dry substrate weight × 100) were examined. The study also evaluated mushroom quality, nutritional composition and bioactive content. The highest intra-cellular polysaccharide (IPS) value (50.93%, w/w) was observed in the substrate containing SMS 90%, while combining SMS with RLV resulted in higher IPS values compared to mixtures that also included wheat bran (WB) and soybean flour (SF). Furthermore, the use of RLV reduced the fat content compared to the control substrate, except in the case of the SMS 50%–RLV 40% substrate, where the highest fat content was observed in the produced mushrooms (4.68% w/w). Additionally, the protein content increased with the use of RLV. The highest triterpene content was found in the SMS 90%–RLV 10% (11.52 ursolic acid mg/g d.w.). However, the control substrate exhibited the fastest Kr (6.5 mm/d), as well as the highest BE (87.8%) and total phenolic compound value (30.31 mg GAE/g d.w.). Significant antioxidant activity was observed in all extracts, while the total flavonoid content was low. Glucose was the dominant monosaccharide (over 51.5%, w/w), and linoleic acid (18:2; over 57.05%, w/w) was the primary fatty acid across all mushrooms. This study also enhances our knowledge by which SMS and RLV influence the NFE2L2/HMOX-1 molecular pathway, thereby affecting specific antioxidant-related genes. These effects were observed through the impact of P. ostreatus protein and carbohydrate extracts on LPS-challenged THP-1-derived macrophages. A positive impact on the gene expression of HMOX1, CAT and NFE2L2 during incubation with the aforementioned samples was observed. These findings support the sustainable use of agricultural by-products in mushroom cultivation, offering an environmentally friendly approach while producing valuable products like mushrooms. Full article
(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)
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27 pages, 5684 KiB  
Review
Membrane-Assisted Dark Fermentation for Integrated Biohydrogen Production and Purification: A Comprehensive Review
by Octavio García-Depraect, Laura Vargas-Estrada, Raúl Muñoz and Roberto Castro-Muñoz
Fermentation 2025, 11(1), 19; https://doi.org/10.3390/fermentation11010019 - 3 Jan 2025
Viewed by 1047
Abstract
The aim of this review is to provide a comprehensive analysis of the membrane-assisted dark fermentation process for bioH2 production and purification. This review initially analyses the need for and the current state of the art in H2 production through dark [...] Read more.
The aim of this review is to provide a comprehensive analysis of the membrane-assisted dark fermentation process for bioH2 production and purification. This review initially analyses the need for and the current state of the art in H2 production through dark fermentation, evaluating the research landscape and the maturity level of the technology. Key factors influencing the dark fermentation process are then examined, along with emerging research trends in membrane-assisted fermentative H2 production systems. This review subsequently addresses the challenges inherent to dark fermentation and explores potential opportunities to enhance H2 production efficiency. Special attention is given to membrane technology as a promising strategy for process intensification in bioH2 production and recovery. Finally, this review provides an in-depth discussion of inorganic membranes, mixed matrix membranes (MMMs), and thin and ultrathin membranes, evaluating each membrane type in terms of its advantages, limitations, and purification performance. This review offers valuable insights into intensifying the dark fermentation process by leveraging membrane technology to enhance bioH2 production and purification efficiency. Full article
(This article belongs to the Special Issue Bioprocesses for Biomass Valorization in Biorefineries)
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15 pages, 2147 KiB  
Article
Impact of Dried Stems on the Chemical Profile of Passito Wines: A Case Study of Four Veneto Varieties
by Giovanni Luzzini, Loris Colognato, Leonardo Vanzo, Jessica Anahi Samaniego Solis, Naíssa Prévide Bernardo, Rosario Pascale, Beatrice Perina, Giacomo Cristanelli, Maurizio Ugliano and Davide Slaghenaufi
Fermentation 2025, 11(1), 18; https://doi.org/10.3390/fermentation11010018 - 3 Jan 2025
Viewed by 685
Abstract
In winemaking, the use of stems during fermentation is rarely employed due to some undesirable side effects. While the effect of fresh stems on wine is extensively studied, to date limited information is available about the effect of dried stems. This study aimed [...] Read more.
In winemaking, the use of stems during fermentation is rarely employed due to some undesirable side effects. While the effect of fresh stems on wine is extensively studied, to date limited information is available about the effect of dried stems. This study aimed to investigate the impact of dried stems on the chemical and sensory profile of passito wines. Four withered grape varieties were selected for winemaking: three red and one white from the Verona area. Grapes were fermented with and without withered stems. A major impact on enological parameters, in particular pH and total polyphenols, was observed. In terms of volatile compounds, no release of C6 alcohols—compounds with undesirable herbaceous odors—was detected. Varietal-dependent release of 3-isobutyl-2-methoxypyrazine (IBMP) was also observed; however in most cases, the content was below the odor threshold. Furthermore, dried stems significantly decreased methanethiol content, likely due to adsorption phenomena. Minor differences were observed in acetate esters, terpenes, and norisoprenoids, though these were not consistent across all wine types. From a sensory point of view, a significant variety-dependent effect was observed, mostly due to IBMP, ethyl acetate, and β-damascenone. Full article
(This article belongs to the Special Issue Wine Aromas: 2nd Edition)
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27 pages, 2642 KiB  
Review
Redox Potential and Its Control in Research and Commercial Wine Fermentations
by James Nelson, Roger Boulton and André Knoesen
Fermentation 2025, 11(1), 9; https://doi.org/10.3390/fermentation11010009 - 2 Jan 2025
Viewed by 709
Abstract
Redox potential is a solution property that influences specific yeast and bacterial activities and the rate of fermentation completion. There is a need to control it if reproducible fermentation outcomes are to be achieved and reliable conclusions are drawn at both the research [...] Read more.
Redox potential is a solution property that influences specific yeast and bacterial activities and the rate of fermentation completion. There is a need to control it if reproducible fermentation outcomes are to be achieved and reliable conclusions are drawn at both the research and commercial scale of wine fermentation. Desirable outcomes that have been observed so far in wine fermentation include the prevention of sluggish and incomplete fermentations, an enhancement in cell viability, increases in the maintenance rate of non-growing cells, and the avoidance of hydrogen sulfide formation when elemental sulfur is present. Other expected fermentation outcomes include changes in the ratios of glycerol and succinate to ethanol, certain aroma and flavor components, and sulfite formation from sulfate in the juice. The juice composition determines the redox potential’s initial value, and the yeast strain’s interaction with the changing juice composition determines the pattern of the potential during fermentation. This interaction also establishes the dynamic response of the prevailing redox buffer to disturbances and the ability to control the potential during fermentation. The chemical reaction sequence, entities, and speciation thought to be responsible for establishing the redox potential in juices and wine are described. A quantitative model for control purposes remains elusive. Examples of the role of added iron in juice, different yeast strains, ambient light, and the addition of external hydrogen peroxide on the response of the potential are presented. Recent examples of controlling the redox potential during white wine and red wine fermentation at a commercial scale are presented, and areas for future research are identified. Full article
(This article belongs to the Section Fermentation Process Design)
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13 pages, 978 KiB  
Article
Development of Starter Cultures for Precision Fermentation of Kombucha with Enriched Gamma-Aminobutyric Acid (GABA) Content
by Geun-Hyung Kim, Kwang-Rim Baek, Ga-Eun Lee, Ji-Hyun Lee, Ji-Hyun Moon and Seung-Oh Seo
Fermentation 2025, 11(1), 17; https://doi.org/10.3390/fermentation11010017 - 2 Jan 2025
Viewed by 755
Abstract
Kombucha, a fermented tea beverage, is produced through the symbiotic interaction of several microbial strains, including acetic acid bacteria, lactic acid bacteria, and yeast, collectively known as symbiotic culture of bacteria and yeast (SCOBY). As its health benefits and distinctive flavor gain wider [...] Read more.
Kombucha, a fermented tea beverage, is produced through the symbiotic interaction of several microbial strains, including acetic acid bacteria, lactic acid bacteria, and yeast, collectively known as symbiotic culture of bacteria and yeast (SCOBY). As its health benefits and distinctive flavor gain wider recognition, consumer demand and research on kombucha fermentation have increased. This study focused on developing starter cultures to produce functional kombucha through precision fermentation technology using selected microbial strains newly isolated from food sources. The isolated bacterial and yeast strains were evaluated and selected based on their fermentation characteristics. Notably, a lactic acid bacterial strain was chosen for its ability to overproduce the γ-amino butyric acid (GABA), a functional food component known to enhance cognitive function and reduce mental stress. To produce the GABA-fortified kombucha, selected single strains of Acetobacter pasteurianus, Lactiplantibacillus plantarum, and Saccharomyces cerevisiae were mixed and used as starter cultures. By optimizing the inoculation ratios and initial sugar concentration, a functional kombucha enriched with acetic acid, lactic acid, and GABA was successfully produced. The resulting kombucha demonstrated 2.2 mg/L of GABA production and 1.15 times higher antioxidant activity after the fermentation, highlighting its enhanced health-promoting properties. Full article
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28 pages, 3185 KiB  
Review
Extremophilic Exopolysaccharides: Bioprocess and Novel Applications in 21st Century
by Chandni Upadhyaya, Hiren Patel, Ishita Patel and Trushit Upadhyaya
Fermentation 2025, 11(1), 16; https://doi.org/10.3390/fermentation11010016 - 2 Jan 2025
Viewed by 1118
Abstract
Extremophiles, microorganisms blooming in extreme environmental conditions, hold particular significance in the domain of microbial research. This review paper focuses on extremophilic microorganisms, emphasizing their adaptations and the diverse products they generate, with a particular emphasis on exopolysaccharides (EPSs). EPSs, high molecular weight [...] Read more.
Extremophiles, microorganisms blooming in extreme environmental conditions, hold particular significance in the domain of microbial research. This review paper focuses on extremophilic microorganisms, emphasizing their adaptations and the diverse products they generate, with a particular emphasis on exopolysaccharides (EPSs). EPSs, high molecular weight carbohydrate biopolymers, stand out as valuable products with applications across various industries. The review explores EPS production by bacteria in extreme conditions, including thermophilic, halophilic, and psychrophilic environments. Noteworthy examples, such as B. thermantarcticus and H. smyrnensis AAD6T, highlight the vast potential of extremophiles in EPS production. Additionally, the paper explores the major synthesis pathways of EPSs, shedding light on the factors influencing biosynthesis. The commercial significance of EPSs, especially for extremophiles, is underlined by their applications in medicine, food, environmental protection, agriculture, cosmetics, and more. Furthermore, the review sheds light on the role of extremophiles in various ecosystems, such as acidophiles, alkaliphiles, halophiles, hyperthermophiles, oligotrophs, osmophiles, piezophiles, and radioresistant organisms. This comprehensive analysis highlights the broad impact of extremophilic microorganisms and their EPS products in scientific exploration and commercial innovation. Full article
(This article belongs to the Section Fermentation Process Design)
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