Fermentation

11 pages, 269 KB

Open AccessBrief Report

Arachidonic Acid Production by Mortierella alpina on Brewery Spent Malt Enriched with Vegetable Oils Using Solid-State Fermentation

by Silvia Stredanská, Janka Kubincová, Mária Kopuncová, Eugen Kiss, Stanislav Baxa and Miroslav Stredanský

Fermentation 2026, 12(8), 394; https://doi.org/10.3390/fermentation12080394 - 21 Aug 2026

Viewed by 233

Abstract

Arachidonic acid (AA) is a high-value long-chain polyunsaturated fatty acid commonly produced by submerged fermentation of oleaginous fungi. Solid-state fermentation (SSF) using low-cost agro-industrial by-products represents a promising alternative approach for sustainable microbial lipid production. In this study, spent malt, a by-product of [...] Read more.

Arachidonic acid (AA) is a high-value long-chain polyunsaturated fatty acid commonly produced by submerged fermentation of oleaginous fungi. Solid-state fermentation (SSF) using low-cost agro-industrial by-products represents a promising alternative approach for sustainable microbial lipid production. In this study, spent malt, a by-product of the brewing industry, was evaluated as a solid substrate for AA production by Mortierella alpina under SSF conditions. Four M. alpina strains were screened for growth, lipid accumulation, and AA production, and M. alpina 959 was selected as the most promising strain. The effects of nitrogen supplementation and oil incorporation on biomass formation, lipid accumulation, and AA productivity were subsequently investigated. Sunflower oil incorporation into spent malt-based substrates improved AA productivity under the most favorable conditions, resulting in an AA proportion of 38.6% of total fatty acids and 102.5 mg AA g⁻¹ of final dry mass of the SSF system (FDW-SC). Comparison of selected vegetable oils further demonstrated that the lipid source affected AA production, while having only a limited effect on fungal growth and total lipid accumulation. Overall, this study demonstrates the feasibility of spent malt-based SSF for AA production by M. alpina and highlights the valorization of brewery spent malt as a low-cost agro-industrial by-product for the production of value-added microbial lipids. Full article

(This article belongs to the Section Fermentation Process Design)

16 pages, 2899 KB

Open AccessArticle

Effects of Controlled Partial Fermentation on the Composition and Sensory Profile of Pedro Ximénez Wines

by Fernando Sánchez-Suárez, Isidoro Lucena, Nieves López de Lerma and Rafael A. Peinado

Fermentation 2026, 12(8), 393; https://doi.org/10.3390/fermentation12080393 - 21 Aug 2026

Viewed by 306

Abstract

Pedro Ximénez sweet wines are traditionally produced from raisined grapes and are characterised by very high sugar and ethanol contents. However, there is growing interest in wines with lower sweetness and improved sensory balance. The aim of this study was to evaluate the [...] Read more.

Pedro Ximénez sweet wines are traditionally produced from raisined grapes and are characterised by very high sugar and ethanol contents. However, there is growing interest in wines with lower sweetness and improved sensory balance. The aim of this study was to evaluate the effect of controlled partial fermentation of Pedro Ximénez raisined grape must prior to fortification on the chemical and sensory properties of the resulting wines. Fermentations were conducted until ethanol concentrations of 3.0, 5.0, 6.5, and 7.7% (v/v) were reached, after which fermentation was arrested, and all wines were standardized to a final ethanol concentration of 9% (v/v). Fermentation progression resulted in a reduction of residual sugar content from 445 to 313 g/L and significant increases in titratable acidity, volatile acidity, glycerol, higher alcohols, ethyl acetate, and 2-phenylethanol. Hierarchical cluster analysis confirmed that fermentation degree was the main factor driving wine differentiation. Sensory evaluation showed that partial fermentation reduced the intensity of characteristic descriptors such as honey, raisin, and fig while simultaneously decreasing sweetness perception and increasing freshness and overall balance. Wines fermented to 6.5 and 7.7% (v/v) ethanol received the highest preference scores from the expert sensory panel. These results indicate that controlled partial fermentation is a feasible technological strategy for modifying the composition and sensory profile of Pedro Ximénez wines and provide a basis for further optimization of alternative, less sweet Pedro Ximénez-style wines. Full article

(This article belongs to the Special Issue Wine and Beer Fermentation, 3rd Edition)

► Show Figures

Figure 1

25 pages, 2754 KB

Open AccessSystematic Review

Progress in Additives That Promote Humification During Agricultural Waste Composting

by Qian Zhang, Zonglu Yao, Lixin Zhao, Jing Feng, Juan Luo, Jiadong Yu and Ruixia Shen

Fermentation 2026, 12(8), 392; https://doi.org/10.3390/fermentation12080392 - 21 Aug 2026

Viewed by 412

Abstract

Aerobic composting converts agricultural waste into stable, humus-rich products, and the application of exogenous additives is an efficient strategy to enhance humification. This systematic review synthesized studies published between 2023 and 2026 on additives that promote humification during agricultural waste composting. Based on [...] Read more.

Aerobic composting converts agricultural waste into stable, humus-rich products, and the application of exogenous additives is an efficient strategy to enhance humification. This systematic review synthesized studies published between 2023 and 2026 on additives that promote humification during agricultural waste composting. Based on the distribution of the retrieved literature, additives are categorized into inorganic additives, organic additives, biological strategies, and composite systems, and the effects and mechanisms of each category are systematically discussed. Iron-based additives achieve the highest humic acid (HA) increases of 82–267% through Fenton-like redox catalysis. Clay minerals and biochar produce moderate HA enhancements of 25–163% via physical structuring and surface adsorption with broader applicability. Small-molecule precursors and exogenous humic substances achieve HA gains exceeding 100% at sub-percent doses. Biological strategies provide self-sustaining catalytic activity but are sensitive to environmental conditions. Composite additives, the largest category, generally outperform single additives through functional complementarity, though antagonistic effects have also been documented. Cross-study patterns suggest that different feedstocks respond preferentially to distinct additive types, though systematic experimental validation is lacking. Critical gaps between laboratory findings and practical application are identified, including the predominance of small-scale studies, the absence of techno-economic analysis, and the unassessed environmental fate of metal-based additives. Future research priorities include pilot-scale validation under industrial conditions, the establishment of standardized humification metrics, and long-term field monitoring. Full article

(This article belongs to the Special Issue Fermented Biofertilizer Production and Application)

► Show Figures

Graphical abstract

32 pages, 5816 KB

Open AccessReview

A Review on Modeling the Fermentation Process of Dairy Products Using Multi-Omics and Artificial Intelligence Approaches

by Murat Emre Terzioğlu and Zeynep Çağla Tekgül

Fermentation 2026, 12(8), 391; https://doi.org/10.3390/fermentation12080391 - 19 Aug 2026

Viewed by 414

Abstract

In dairy production, the fermentation process is a complex biochemical system that plays a significant role in determining the quality criteria of the final product. Traditional methods for controlling fermentation rely on limited and non-standard process parameters. In recent years, omics technologies have [...] Read more.

In dairy production, the fermentation process is a complex biochemical system that plays a significant role in determining the quality criteria of the final product. Traditional methods for controlling fermentation rely on limited and non-standard process parameters. In recent years, omics technologies have come to the forefront, enabling the monitoring of fermentation dynamics at the molecular level with their current, efficient, and reliable approaches. Thanks to omics approaches such as metabolomics, metagenomics, proteomics, and lipidomics, starter culture behavior, metabolite formation, aroma–texture formation, and microbial interactions in the fermentation process can be characterized more comprehensively. On the other hand, evaluating or calculating high-dimensional omics data using traditional statistical methods presents a challenge. Artificial intelligence applications are overcoming this challenge, offering significant opportunities for the accurate and reliable evaluation of data. Artificial intelligence-powered models hold promise in areas such as predicting fermentation kinetics, process control, optimizing quality criteria, and revealing the therapeutic potential of products through metabolites. This compilation aims to comprehensively address current approaches to modeling the fermentation process and quality parameters of dairy products using multi-omics technologies and artificial intelligence applications. In this respect, it will provide current and important perspectives for industrial applications and future studies. Full article

(This article belongs to the Special Issue Dairy Fermentation from a Microbial Perspective)

► Show Figures

Figure 1

12 pages, 1309 KB

Open AccessArticle

Fermentation Temperature as a Strategy to Limit Hanseniaspora uvarum Proliferation During Spontaneous Wine Fermentation

by Cristobal A. Onetto, Jane McCarthy and Simon A. Schmidt

Fermentation 2026, 12(8), 390; https://doi.org/10.3390/fermentation12080390 - 19 Aug 2026

Viewed by 346

Abstract

Hanseniaspora uvarum is consistently observed as the dominant non-Saccharomyces species in grape juice leading to spontaneous fermentations and is often considered a detrimental factor due to the increased volatile acidity associated with its abundance. This study investigated how fermentation temperature affects the [...] Read more.

Hanseniaspora uvarum is consistently observed as the dominant non-Saccharomyces species in grape juice leading to spontaneous fermentations and is often considered a detrimental factor due to the increased volatile acidity associated with its abundance. This study investigated how fermentation temperature affects the competitive interaction between H. uvarum and Saccharomyces cerevisiae, and how these shifts influence microbial community structure during spontaneous grape juice fermentations. Defined single- and co-inoculated fermentations were conducted across a range of temperatures (17, 23, and 25 °C), and cell abundance was quantified by flow cytometry. In parallel, spontaneous fermentations were monitored using ITS metabarcoding to assess temperature-driven changes in fungal community composition. At 17 °C, H. uvarum dominated early fermentation due to its faster growth rate, resulting in slower sugar consumption and prolonged fermentations. Increasing fermentation temperature enhanced the early growth of S. cerevisiae. Consistent patterns were observed in spontaneous fermentations, where higher temperatures increased the relative abundance of S. cerevisiae and shortened fermentation time. These results demonstrate that fermentation temperature is a major driver of yeast competition and suggest that moderate increases in fermentation temperature may help limit excessive H. uvarum proliferation during spontaneous fermentations. Full article

(This article belongs to the Special Issue Wine and Beer Fermentation, 3rd Edition)

► Show Figures

Figure 1

12 pages, 2479 KB

Open AccessArticle

Co-Digestion as a Strategy to Optimize Anaerobic Digestion Without Pretreatment: Implications for Methane Yield and Process Stability

by Aytac Perihan Akan, Kenan Dalkilic and Aysenur Ugurlu

Fermentation 2026, 12(8), 389; https://doi.org/10.3390/fermentation12080389 - 19 Aug 2026

Viewed by 312

Abstract

Rapid population growth, urbanization, and industrialization are continuously increasing global energy demand while intensifying climate change associated with fossil fuel consumption. In this context, renewable energy production from organic waste has gained increasing attention as a sustainable and environmentally friendly strategy. Anaerobic digestion [...] Read more.

Rapid population growth, urbanization, and industrialization are continuously increasing global energy demand while intensifying climate change associated with fossil fuel consumption. In this context, renewable energy production from organic waste has gained increasing attention as a sustainable and environmentally friendly strategy. Anaerobic digestion (AD) offers significant potential for simultaneous waste stabilization and biomethane generation. However, many previous studies investigating lignocellulosic or nutrient-rich substrates have relied on physical, chemical, or thermal pretreatment methods to enhance biodegradability, despite their additional operational costs, energy consumption, and environmental impacts. Therefore, developing low-cost and pretreatment-free co-digestion strategies remains an important research need. This study investigated the biomethane production potentials of untreated chicken manure (CM) and duckweed (Lemna minor-LM) collected from the final sedimentation tanks of wastewater treatment plants under mono-digestion and co-digestion conditions. The study hypothesized that rapidly growing and widely available LM biomass could enhance methane production without requiring pretreatment. Among all reactors, CM0.75 (75% of the total TS derived from CM and 25% from LM and inoculum) achieved the highest performance with a cumulative biogas production of 5350 mL (74.2% of CH4) and a methane yield of 327 mL CH4/g VS, while mono-digestion of CM resulted in the lowest methane yield of 104 mL CH4/g VS. The results demonstrated that LM biomass naturally proliferating in wastewater treatment plants can be directly utilized as an effective co-substrate to improve biomethane production from poultry wastes. The proposed approach provides a cost-efficient, eco-friendly, and circular-economy-oriented alternative by eliminating the need for pretreatment while simultaneously valorizing problematic biomass generated in wastewater treatment facilities. Full article

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

► Show Figures

Figure 1

16 pages, 1641 KB

Open AccessArticle

Effects of Cold Fermentation and Cold Storage on Type I Sourdough and Bread Properties

by Gulhan Turk, Gorkem Ozulku, Saeideh S. Fatemizadeh, Osman Sagdic and Ömer Şimşek

Fermentation 2026, 12(8), 388; https://doi.org/10.3390/fermentation12080388 - 18 Aug 2026

Viewed by 349

Abstract

The aim of this study is to provide an alternative bakery practice by evaluating the effects of cold fermentation (backslopping at 7 and 15 °C) and cold storage (stored at 7 and 15 °C) after backslopping on Type I sourdough characteristics and the [...] Read more.

The aim of this study is to provide an alternative bakery practice by evaluating the effects of cold fermentation (backslopping at 7 and 15 °C) and cold storage (stored at 7 and 15 °C) after backslopping on Type I sourdough characteristics and the technological performance of the corresponding breads. Sourdough characteristics (pH, acidity, and microbial counts), bread quality (texture and color), storage behavior, and volatile compound profiles (VoC) were investigated to compare the extent to which these treatments improve product quality. No significant difference was observed in pH and total titratable acidity among the sourdoughs. However, the fermentation quotient of the cold storage group was higher than that of the cold fermented group. Backslopping at cold fermentation temperatures (7 and 15 °C) caused a significant reduction in lactic acid bacteria counts. Conversely, cold fermentation and cold storage at 15 °C led to a significant increase in yeast counts. From a technological perspective, bread produced with sourdough backslopped at 15 °C exhibited a higher specific volume than breads produced with the other cold-treated sourdoughs. At the end of the storage period, the bread made with cold-backslopped sourdough at 7 °C had the highest hardness value, while others remained similar. Principal component analysis (PCA) of volatile compounds revealed that cold-stored sourdoughs were clustered apart from room-temperature-stored sourdoughs, mainly driven by ethyl hexanoate and hexyl acetate. Heptanoic acid was among the key VOCs contributing to the positioning of breads made with cold-stored sourdoughs in the PCA. In conclusion, these findings demonstrate that backslopping and storage at 15 °C offer an industrially relevant production strategy while improving textural properties and VoC profiles. Full article

(This article belongs to the Special Issue Biotechnology for Smarter Industrial Fermentation)

► Show Figures

Figure 1

23 pages, 7706 KB

Open AccessArticle

Evaluation of Monascus ruber Inoculum Preparation Strategies and Surfactant Supplementation to Enhance Biopigment Production in a Xylose-Based Medium Derived from Ethanol Biorefinery By-Products

by Willian de S. M. Reis, Gabriel L. de Arruda, Silvio S. da Silva, Arnaldo M. R. Prata and Júlio C. dos Santos

Fermentation 2026, 12(8), 387; https://doi.org/10.3390/fermentation12080387 - 17 Aug 2026

Viewed by 284

Abstract

Bioenergy biorefineries generate lignocellulosic by-products rich in fermentable sugars that can serve as renewable feedstocks for the production of high-value bioproducts, including microbial pigments with promising bioactive properties (antioxidant, antimicrobial, and anticancer). Therefore, this study aimed to identify a suitable inoculum preparation strategy, [...] Read more.

Bioenergy biorefineries generate lignocellulosic by-products rich in fermentable sugars that can serve as renewable feedstocks for the production of high-value bioproducts, including microbial pigments with promising bioactive properties (antioxidant, antimicrobial, and anticancer). Therefore, this study aimed to identify a suitable inoculum preparation strategy, to optimize the culture medium, and to evaluate biopigment production using xylose-based media derived from sugarcane bagasse hemicellulosic hydrolysate (SBHH). Different inoculation strategies were evaluated (cell suspension, whole mycelial discs, and fractionated mycelial discs) and supplementation with Tween 80 (TW80). The medium composition was optimized using a Box–Behnken design, with xylose, yeast extract, and TW80 as variables, and fermentations were then conducted under selected inoculum conditions in semi-defined media and SBHH. The mycelial disc inoculation strategy was selected due to its high biopigment production and lower operational complexity, yielding 8.99, 8.48, and 11.78 AU of yellow, orange, and red biopigments, respectively. The optimized culture composition consisted of 55.65 g/L of xylose, 4.18 g/L of yeast extract, and 15.38 g/L of Tween 80. The cultivation of M. ruber in SBHH resulted in 12.73, 10.75, and 14.56 AU of yellow, orange, and red biopigments, respectively. Thus, the strategy of inoculum preparation associated with non-ionic surfactant proved promising for application in bioenergy biorefineries. Full article

(This article belongs to the Special Issue Microbial Processes for Biomass Conversion to Bioenergy)

► Show Figures

Graphical abstract

19 pages, 4029 KB

Open AccessArticle

Vitis vinifera Leaf Extract as a Sustainable Alternative to Sulphur Dioxide in High-Hydrostatic-Pressure-Treated Fiano Wine

by Mamica Ruci, Renata Kongoli, Rosaria Cozzolino, Cristina Matarazzo, Bruno Testa, Onejda Kyçyk, Julian Karaulli, Massimo Di Renzo, Catello Di Martino, Fatbardha Lamçe and Massimo Iorizzo

Fermentation 2026, 12(8), 386; https://doi.org/10.3390/fermentation12080386 - 15 Aug 2026

Viewed by 274

Abstract

The growing demand for clean-label and low-sulphite wines has increased interest in alternative preservation strategies capable of reducing sulphur dioxide (SO₂) usage while maintaining wine quality and stability. In this study, the effectiveness of Vitis vinifera leaf extract as a natural [...] Read more.

The growing demand for clean-label and low-sulphite wines has increased interest in alternative preservation strategies capable of reducing sulphur dioxide (SO₂) usage while maintaining wine quality and stability. In this study, the effectiveness of Vitis vinifera leaf extract as a natural alternative to sulphur dioxide was evaluated in High Hydrostatic Pressure (HHP)-treated Fiano wines. Three experimental wines were produced: CW (control wine), SW (sulphited wine), and LW (leaf-extract wine). Following alcoholic fermentation, all wines were subjected to HHP treatment (600 MPa for 5 min) and stored at 4 °C for 60 days. Physicochemical parameters, volatile organic compounds (VOCs), and sensory characteristics were evaluated immediately after alcoholic fermentation and after HHP treatment followed by refrigerated storage. Compared with the control wine, LW exhibited approximately 20% higher total polyphenol concentrations, whereas SW showed the greatest preservation of fermentation-derived esters. HHP treatment induced only moderate changes in the volatile fraction, confirming the suitability of this non-thermal technology for wine stabilization. LW wines were characterized by higher abundances of terpene-related compounds, C6 alcohols, medium-chain fatty acids, and phenolic-associated volatiles, resulting in more pronounced floral, balsamic, herbaceous, and vegetal sensory attributes. Principal Component Analysis (PCA) explained 79.0% of the total VOC variability and clearly differentiated LW wines from CW and SW according to their volatile profiles, while sensory analysis confirmed the development of a distinctive aromatic identity associated with grapevine leaf extract. Overall, the results indicate that the combined application of V. vinifera leaf extract and HHP represents a promising strategy for the partial replacement of sulphur dioxide in white winemaking. This integrated approach contributes to wine stabilization while promoting the valorization of grapevine leaves as a sustainable winery by-product within a circular economy framework. Full article

(This article belongs to the Special Issue Recent Advances in the Fermentation of Plant-Based Foods and Beverages)

► Show Figures

Figure 1

21 pages, 968 KB

Open AccessArticle

Effects of Hyperbaric Micro-Oxygenation on the Colour, Total Phenolic Content, Volatile Composition, and Sensory Profile of Vitis vinifera L. cv. Monastrell Grape Must

by Pablo Mompean, José Ramón Acosta-Motos, Llanos Martínez-Martínez, Luis Noguera-Artiaga, Angel A. Carbonell-Barrachina, Patricia Navarro and Antonio José Pérez-López

Fermentation 2026, 12(8), 385; https://doi.org/10.3390/fermentation12080385 - 15 Aug 2026

Viewed by 342

Abstract

Oxygen management during alcoholic fermentation can redirect phenolic reactions and yeast-derived aroma formation, but the use of mild hyperbaric conditions as a micro-oxygenation strategy remains poorly characterized. This study evaluated the effects of hyperbaric micro-oxygenation at 1.40 ATA in a stainless-steel chamber on [...] Read more.

Oxygen management during alcoholic fermentation can redirect phenolic reactions and yeast-derived aroma formation, but the use of mild hyperbaric conditions as a micro-oxygenation strategy remains poorly characterized. This study evaluated the effects of hyperbaric micro-oxygenation at 1.40 ATA in a stainless-steel chamber on the fermentation of Vitis vinifera L. cv. Monastrell must, comparing treated and non-micro-oxygenated samples at the initial, mid-fermentation, and final stages. Physicochemical parameters, CIELAB color coordinates, total phenolic content, volatile organic compounds, and descriptive sensory attributes were analyzed. Hyperbaric micro-oxygenation did not impair fermentation completion, as both treatments reached final residual sugar values of 2.2 g/L and alcohol contents of 15.2–15.4% v/v. The treatment promoted a darker final chromatic profile, with lower L*, the highest overall color difference, and a marked increase in total phenolic content, reaching 1900.9 mg gallic acid equivalents/L compared with 1593.2 mg gallic acid equivalents/L in control. Volatile changes were compound, and stage-dependent, indicating modulation rather than generalized enhancement of aroma formation. Ethyl esters, particularly ethyl octanoate and ethyl decanoate, increased markedly under micro-oxygenation, while acetate esters such as ethyl acetate and hexyl acetate decreased relative to the initial must, reflecting a shift in the balance of aroma-active compounds rather than a uniform increase across all volatile families. These findings support mild hyperbaric micro-oxygenation as a promising non-thermal strategy to modulate Monastrell fermentation quality. Full article

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

► Show Figures

Figure 1

21 pages, 3358 KB

Open AccessArticle

Performance of a Continuous Dark–Photo Fermentation System to Produce Hydrogen from Simulated Sugar–Rich Processing Wastewater Under Suboptimal pH and Temperature Conditions

by Soumya Gupta, Annabel Fernandes, Laura Grasa, Carlos Rubio and Jesús Salafranca

Fermentation 2026, 12(8), 384; https://doi.org/10.3390/fermentation12080384 - 13 Aug 2026

Viewed by 396

Abstract

The integration of coupled dark fermentation (DF) and photofermentation (PF) systems represents a promising approach for concurrent H₂ production and organic load reduction in carbohydrate–rich wastewater. However, their behavior under non–optimized, continuous industrial operation remains inadequately characterized, hindering practical implementation. This case [...] Read more.

The integration of coupled dark fermentation (DF) and photofermentation (PF) systems represents a promising approach for concurrent H₂ production and organic load reduction in carbohydrate–rich wastewater. However, their behavior under non–optimized, continuous industrial operation remains inadequately characterized, hindering practical implementation. This case study evaluated an integrated DF–PF system treating a synthetic sugar mixture mimicking acidic fruit and dairy processing wastewater. The system presented herein (5-L reactors) serves as an initial prototype to facilitate scaling to both pilot (40-L reactors) and, ultimately, industrial (600-L) scales using real effluents within the framework of a research project. The bioreactors were operated continuously with a 10 h hydraulic retention time and an organic loading rate of 2.5 g COD L⁻¹ d⁻¹. The pH and temperature were monitored but intentionally left uncontrolled. The DF stage facilitated by hydrogen–producing bacteria achieved H₂ concentrations of up to 57% (v/v) and a maximum production rate of 177 mL H₂ L⁻¹ d⁻¹; however, it demonstrated notable process instability due to the absence of controls. In contrast, the PF stage exhibited negligible H₂ production (1.8% v/v) attributable to the displacement of Rhodopseudomonas species by microbial competition, thereby functioning predominantly as a polishing step. Overall, the coupled system achieved an average COD removal of 34%, highlighting the functional differentiation between stages and identifying microbial competition as the primary constraint under suboptimal conditions. Full article

(This article belongs to the Special Issue Recent Advancements in Fermentation Technology: Biofuels Production)

► Show Figures

Figure 1

17 pages, 870 KB

Open AccessArticle

Enzymatically Pretreated Red-Fleshed Pitaya (Hylocereus polyrhizus) as a Co-Fermentation Substrate Improves the Nutritional Quality and Sensory Profile of Black Rice Wine

by Chaoyang Zhu, Dina Zhu, Bei Liao, Zhanlei Fan, Yongmei Hu, Shumiao Zhao, Yunxiang Liang and Jinshan Li

Fermentation 2026, 12(8), 383; https://doi.org/10.3390/fermentation12080383 - 12 Aug 2026

Viewed by 270

Abstract

Black rice wine is a traditional cereal-based fermented beverage valued for its colour, flavour and bioactive constituents. However, product innovation is needed to meet increasing consumer demand for fruit-derived aroma, nutritional quality and functional attributes. To address this demand, we developed an integrated [...] Read more.

Black rice wine is a traditional cereal-based fermented beverage valued for its colour, flavour and bioactive constituents. However, product innovation is needed to meet increasing consumer demand for fruit-derived aroma, nutritional quality and functional attributes. To address this demand, we developed an integrated processing strategy combining enzymatic pretreatment of pitaya pulp with stage-specific co-fermentation, an approach that has not been systematically evaluated in rice wine systems. Pitaya pulp was first pretreated with pectinase using an orthogonal design to optimise juice yield and betacyanin retention; the enzymatically pretreated pitaya pulp was then introduced either as pulp or as fermented pitaya wine at the saccharification, tank-flushing or ageing stage. The resulting wines were compared with a pitaya-free control and three commercial black rice wines on the basis of physicochemical indices, phenolic and pigment contents, amino acid composition, mineral composition and fuzzy mathematics-based sensory evaluation. Pitaya pulp added at saccharification (Sample THJ) yielded the strongest functional and nutritional profile, with the highest total phenolic content (629.74 mg/L); high flavonoid content (152.07 mg/L); enrichment in Mg, K and Mn; and a broader taste-active amino acid profile. By contrast, pitaya pulp added during tank flushing (Sample CHJ) achieved the highest sensory score (85.3) and had the highest anthocyanin content. These findings indicate that the timing and form of pitaya addition determine the balance between functional enrichment, pigment retention and sensory quality. Co-fermentation with red-fleshed pitaya, particularly the early addition of enzymatically pretreated pitaya pulp, provides a practical route for the development of fruit-flavoured black rice wine with improved nutritional composition and consumer appeal, suggesting the potential for enhanced functional value. Full article

(This article belongs to the Special Issue Recent Advances in the Fermentation of Plant-Based Foods and Beverages)

► Show Figures

Figure 1

16 pages, 257 KB

Open AccessArticle

Effect of Genotype and Microbial Inoculants on Quality, Fermentation, and In Vitro Digestibility of Barley at Early Dough Stage of Maturity

by Umair Ahsan, Derya Merve Karagöz, Muhammad Shazaib Ramay, Syed Umer Akhter, Anas Tahir, Bekir Tosun, Ifrah Raza, Murat Er, Muhammad Kashif Yar and Eren Kuter

Fermentation 2026, 12(8), 382; https://doi.org/10.3390/fermentation12080382 - 12 Aug 2026

Viewed by 317

Abstract

A 2 × 2 × 2 factorial experiment was conducted to study the individual and combined effects of barley variety (Tarım 92 and Bravo), homofermentative inoculant (HMF; Lactobacillus plantarum and Enterococcus faecium), and heterofermentative inoculant (HTF; Lactobacillus buchneri) on the fermentation [...] Read more.

A 2 × 2 × 2 factorial experiment was conducted to study the individual and combined effects of barley variety (Tarım 92 and Bravo), homofermentative inoculant (HMF; Lactobacillus plantarum and Enterococcus faecium), and heterofermentative inoculant (HTF; Lactobacillus buchneri) on the fermentation characteristics, chemical composition, nutritive value indices, and in vitro digestibility of whole-crop barley silages which were harvested at the early dough stage. Forty-eight laboratory silos (six replicates per treatment) were ensiled for 120 days. Tarım 92 silage exhibited superior fermentation stability across all treatments, with pH ranging from 4.11 to 4.30, Flieg points of 102.94–115.47, and lower NH₃-N concentrations (142.01–173.72 mg/kg TN (total nitrogen)), reflecting better protein preservation than Bravo silage. In contrast, the poorest fermentation outcome (pH 5.24; Flieg 47.06; NH₃-N 307.48 mg/kg TN) was exhibited by the Bravo silage inoculated with only homofermentative inoculants. Significant three-way interaction effects were detected among barley variety, homofermentative inoculant, and heterofermentative inoculant (p < 0.05). The dual-inoculated Tarım 92 silage showed the optimum in vitro digestibility and nutritional value (TDN 77.14%; NEL 1.81 Mcal kg⁻¹ DM; RFV 176.25; ADF 18.75%; IVOMD 65.72%; predicted DMI 3.06% BW), while higher amounts of butyric acid and NH₃-N suggested that better nutritional value was not always accompanied by better protein preservation. The combined inoculation also yielded the best outcomes within Bravo treatments (RFV 144.00), whereas HTF inoculation alone reduced IVDMD and IVOMD below uninoculated controls. Overall, these results show that the response to microbial inoculation is genotype-dependent and a combination of homofermentative and heterofermentative inoculation for high-dry-matter barley varieties can enhance nutritive value and digestibility. However, fermentation quality indicators, particularly butyric acid and NH₃-N, require consideration in the selection of technique. Full article

(This article belongs to the Special Issue Application of Fermentation Technology in Animal Nutrition: 3rd Edition)

18 pages, 1147 KB

Open AccessArticle

Effects of Molasses-Based Liquid Feeds Containing Conventional Urea or Commercial Fat-Coated Urea Product on In Vitro Rumen Fermentation, Gas Kinetics, and Substrate Degradability

by Yotsapon Yangngam, Seangla Cheas, Chanon Suntara, Metha Wanapat, Juan J. Loor and Anusorn Cherdthong

Fermentation 2026, 12(8), 381; https://doi.org/10.3390/fermentation12080381 - 11 Aug 2026

Viewed by 462

Abstract

This study evaluated molasses-based liquid feeds containing conventional urea or a commercial fat-coated urea product marketed as slow-release urea (SRU). The effects on in vitro gas-production kinetics, rumen fermentation, and substrate degradability were examined. Treatments followed a 5 × 3 factorial design. The [...] Read more.

This study evaluated molasses-based liquid feeds containing conventional urea or a commercial fat-coated urea product marketed as slow-release urea (SRU). The effects on in vitro gas-production kinetics, rumen fermentation, and substrate degradability were examined. Treatments followed a 5 × 3 factorial design. The five formulations were 0% urea, 5% urea, 10% urea, 5% SRU, and 10% SRU. Each formulation was supplied at 0.9%, 1.8%, or 2.7% of the 0.5 g basal substrate dry matter (DM). Four independent incubation runs were conducted. A formulation × inclusion-level interaction was detected for gas-production lag time (p = 0.0046). The shortest lag time occurred with 10% SRU supplied at 2.7%. At 48 h, the 0.9% inclusion level resulted in greater dry matter and organic matter degradability than the 1.8% and 2.7% levels. The 5% SRU formulation had the lowest 24 h degradability, whereas 10% SRU had the greatest 48 h dry matter degradability. Ammonia nitrogen (NH₃-N) was analyzed separately at each sampling time. The 10% conventional urea formulation had the greatest NH₃-N concentration at 1 and 2 h. The 10% SRU formulation had the greatest concentration at 4, 6, and 12 h. These within-time differences do not demonstrate different ammonia-release patterns over time. At 12 h, the 10% SRU formulation had the greatest total volatile fatty acid concentration and propionate molar proportion. Protozoal counts were unaffected. The results reflect differences among the complete liquid-feed formulations. They do not provide direct evidence of controlled ammonia release or improved nitrogen–carbohydrate synchronization. Further in vivo studies using compositionally balanced formulations are required. Full article

(This article belongs to the Special Issue Fermentation Technologies for Sustainable Animal Feed)

► Show Figures

Figure 1

31 pages, 12782 KB

Open AccessArticle

Gut Microbiome and Metabolome Responses to Fermented Fish Paste (Kapi-pla) in a Simulated Colonic Model of Alzheimer’s Disease

by Nisa Alfilasari, Nattha Tampanna, Nualpun Sirinupong and Santad Wichienchot

Fermentation 2026, 12(8), 380; https://doi.org/10.3390/fermentation12080380 - 11 Aug 2026

Viewed by 319

Abstract

Bioactive peptides (BPs) are increasingly recognized for modulating the gut microbiome, metabolome, and brain function via the gut–brain axis. Kapi-pla, a traditional Thai fermented freshwater fish paste rich in proteins and peptides, is widely consumed in Southern Thailand. This study profiled the peptides [...] Read more.

Bioactive peptides (BPs) are increasingly recognized for modulating the gut microbiome, metabolome, and brain function via the gut–brain axis. Kapi-pla, a traditional Thai fermented freshwater fish paste rich in proteins and peptides, is widely consumed in Southern Thailand. This study profiled the peptides of Phatthalung Kapi-pla (PK) and Songkhla Kapi-pla (SK) and investigated their impacts on gut microbiota and metabolome using a simulated colonic fermentation model with fecal samples from patients with Alzheimer’s disease (AD). Microbial composition and metabolites were assessed by 16S rRNA sequencing and LC–MS/MS, respectively. After 24 h fermentation, PK modestly increased Shannon diversity relative to the unsupplemented control, with richness indices unchanged, reduced Proteobacteria abundance and opportunistic pathogens such as Escherichia–Shigella and Klebsiella, and selectively increased short- and branched-chain fatty acids, including acetate, propionate, butyrate, and iso-valerate. PK further enhanced neuroactive metabolites relevant to AD pathology, underscoring its potential as a functional food ingredient to ameliorate AD-associated dysbiosis and support gut–brain axis health. Full article

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

► Show Figures

Graphical abstract

17 pages, 429 KB

Open AccessArticle

The Effect of Pre-Fermentative Thermo-Maceration and Apple Pomace Addition on Phenolic Content and Volatile Profile of Hard Cider

by Luis F. Castro, Tessa A. J. Murphree, Kate P. Perry, Sean Kuster and L. Federico Casassa

Fermentation 2026, 12(8), 379; https://doi.org/10.3390/fermentation12080379 - 10 Aug 2026

Viewed by 511

Abstract

The aim of this study was to investigate the effects of thermo-maceration and apple pomace addition on phenolic compound extraction during cider fermentation and on the volatile profile of the final product. Jonagold apples were milled, and the juice was divided into four [...] Read more.

The aim of this study was to investigate the effects of thermo-maceration and apple pomace addition on phenolic compound extraction during cider fermentation and on the volatile profile of the final product. Jonagold apples were milled, and the juice was divided into four groups: (1) Control: no apple pomace or thermo-maceration; (2) Control TM: thermo-maceration only; (3) CiderAP: apple pomace addition only; and (4) CiderAPTM: apple pomace addition combined with thermo-maceration. Apple pomace was added at 50% of the average pomace weight created during milling, and thermo-maceration consisted of heating the juice to 60 °C for 1 h prior to fermentation. Ciders were fermented at 20 ± 1 °C for 14 days. CiderAP and CiderAPTM showed higher total phenolic content (TPC) and antioxidant activity than the control treatments. The volatile profile was also modified, with CiderAPTM showing the highest phenylethyl alcohol concentration and esters exhibiting compound-specific responses. Statistical analysis showed that only apple pomace addition significantly increased TPC and antioxidant activity, while both apple pomace addition and thermo-maceration affected the volatile profile. Under the conditions evaluated, thermo-maceration did not increase TPC or antioxidant activity beyond the effect of apple pomace addition but did modify the volatile profile of the ciders. Further research should evaluate different thermo-maceration temperatures and durations to determine its potential application in cider production. The findings of this study provide valuable insights for cider makers on the valorization of apple pomace and potential use of thermo-maceration in cider production. Full article

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

► Show Figures

Figure 1

22 pages, 349 KB

Open AccessArticle

Effects of Replacing Concentrate Feed with Carob (Ceratonia siliqua) Pods on Growth Performance, Carcass Characteristics, Meat Quality, and Rumen Fermentation in Assaf Lambs

by Soha Ghzayel, Ahmed E. Kholif, Alexey Díaz-Reyes, Bassam Abu Aziz, Halimeh Zoabi, Raouia Ben Rhouma, Sawsan Hassan, Secundino López, Adel M. M. Kholif, Silvia Parrini, Andrea Confessore and Hajer Ammar

Fermentation 2026, 12(8), 378; https://doi.org/10.3390/fermentation12080378 - 10 Aug 2026

Viewed by 307

Abstract

This study examined the effects of replacing 25% (P25) or 50% (P50) of concentrate dry matter (DM) with sun-dried carob (Ceratonia siliqua L.) pods on growth performance, apparent nutrient digestibility, carcass traits, meat quality, serum biochemistry, and rumen microbiology in growing Assaf [...] Read more.

This study examined the effects of replacing 25% (P25) or 50% (P50) of concentrate dry matter (DM) with sun-dried carob (Ceratonia siliqua L.) pods on growth performance, apparent nutrient digestibility, carcass traits, meat quality, serum biochemistry, and rumen microbiology in growing Assaf lambs. Twenty-four weaned male Assaf lambs (initial body weight [BW] 27.0 ± 0.5 kg; 2.5 months of age) were randomly assigned to three dietary treatments (n = 8 per group) in a completely randomized design and fed for 16 weeks. P50 achieved the highest ANCOVA-adjusted least squares mean final BW (53.0 kg) and average daily gain (ADG) (220.8 g/d), followed by P25 (51.1 kg; 203.3 g/d) and the control (46.2 kg; 160.2 g/d) (p < 0.001). Feed conversion ratio (FCR) improved from 8.99 in the control to 6.16 and 6.11 in P25 and P50, respectively, with no significant difference between the two carob-supplemented groups (p < 0.001). Apparent DM and organic matter (OM) digestibility increased with carob inclusion at both 3 and 6 months of age (p ≤ 0.0001). Cold carcass weight (CCW) was higher in carob-supplemented lambs (p < 0.001), whereas carcass muscle proportion did not differ among treatments (p = 0.688), and carcass fat proportion was higher in P25 than in the control (p = 0.039). Warner–Bratzler shear force declined progressively with carob inclusion (p < 0.001), indicating improved meat tenderness. Serum total protein was highest in P25, whereas blood urea nitrogen (BUN), low-density lipoprotein (LDL), and glutamate oxaloacetate transaminase (GOT) decreased with carob inclusion (p < 0.001). Rumen pH was highest in P25 (6.40), total bacterial and lactic acid bacteria (LAB) counts increased, and protozoa counts declined (p < 0.001). Because carob pods replaced concentrate, rather than being added to an isonitrogenous diet, the combined effects of pods per se, reduced crude protein supply, and altered energy density must all be considered when interpreting the results. These findings support carob pods as a practical, locally available partial substitute for concentrate feed in Assaf lamb production under Mediterranean and Near Eastern conditions. Full article

(This article belongs to the Special Issue Fermentation Technologies for Sustainable Animal Feed)

17 pages, 786 KB

Open AccessArticle

Effects of Extraction Methods on Inulin, Fructooligosaccharides and Microbial Inulinase Production from Stevia rebaudiana

by Gokce Kucuk, Muge Canatar, Selin Basmak, Selime Benemir Erkan Ünsal, Hilal Nur Gürler Tufan, Ali Ozcan, Mustafa Karhan, Ercan Yatmaz, İbrahim Yavuz and Irfan Turhan

Fermentation 2026, 12(8), 377; https://doi.org/10.3390/fermentation12080377 - 10 Aug 2026

Viewed by 362

Abstract

In this study, Stevia fractions (root, leaf, stem and their mixture) were used for inulin extraction using aqueous extraction, enzyme-assisted extraction and enzyme-assisted decanter extraction. The extracts were used as carbon sources in submerged (SmF) fermentation, whereas the remaining solid residues were used [...] Read more.

In this study, Stevia fractions (root, leaf, stem and their mixture) were used for inulin extraction using aqueous extraction, enzyme-assisted extraction and enzyme-assisted decanter extraction. The extracts were used as carbon sources in submerged (SmF) fermentation, whereas the remaining solid residues were used as substrates in solid-state (SSF) fermentation for inulinase and FOS production by Aspergillus niger. The highest inulin concentration was obtained from the root extract produced by aqueous extraction at a 1:5 (w/v) ratio (197.55 g/L). The highest fructooligosaccharides (FOS) concentration (12.64 g/L) was achieved by root enzyme-assisted extraction. In SmF, the highest total FOS concentration (13.99 g/L) was obtained from leaf enzyme-assisted extracts (LEE), whereas in SSF, the maximum total FOS concentration (20.80 g/L) was achieved using leaf enzyme-assisted decanter extracts. Inulinase from the aqueous root extracts was 609.72 U/mL during SmF and the leaf enzyme-assisted decanter extracts was 450.86 U/mL during SSF. Inulin extraction from fractions of Stevia, high inulinase production in Smf, and enhanced FOS production from residual biomass in SSF enable the generation of multiple value-added products and support circular economy and biorefinery principles. Full article

(This article belongs to the Special Issue Process Intensification in Microbial Biotechnology for Fermentation)

► Show Figures

Figure 1

22 pages, 2707 KB

Open AccessReview

Microorganisms in Fermented Foods and Their Contribution to Oral Health: A Narrative Review

by Georgios Chrysochoou, Socratis Thomaidis, Maria Antoniadou and Theodoros Varzakas

Fermentation 2026, 12(8), 376; https://doi.org/10.3390/fermentation12080376 - 9 Aug 2026

Viewed by 475

Abstract

Fermented foods contain diverse microorganisms that may influence oral microbial ecology and contribute to oral health. This narrative review aimed to examine the current evidence regarding microorganisms present in fermented foods and their role in oral health promotion. Twenty relevant clinical, experimental, observational, [...] Read more.

Fermented foods contain diverse microorganisms that may influence oral microbial ecology and contribute to oral health. This narrative review aimed to examine the current evidence regarding microorganisms present in fermented foods and their role in oral health promotion. Twenty relevant clinical, experimental, observational, and review studies published between 2016 and 2026 were identified through a structured literature search and critically synthesized according to major thematic areas, including oral microbiota modulation, dental caries prevention, periodontal health, probiotic delivery systems, and evidence from review articles. The findings appear to indicate that fermented food-derived microorganisms may reduce cariogenic and periodontal pathogens, modulate oral biofilms, improve gingival health, and promote microbial homeostasis. Yogurt, kefir, fermented dairy products, and kimchi-derived microorganisms were the most frequently investigated sources. Emerging evidence further suggests that the benefits of these microorganisms are linked to ecological regulation of the oral microbiome and host–microbe interactions rather than direct antimicrobial activity alone. Microorganisms associated with fermented foods may therefore represent promising functional dietary components for supporting oral health and complementing preventive oral healthcare strategies. Further well-designed clinical studies are needed to establish strain-specific recommendations and explore the potential of postbiotic applications in dentistry. Full article

(This article belongs to the Special Issue Microbial Ecosystems in Fermented Foods)

► Show Figures

Figure 1

18 pages, 2280 KB

Open AccessArticle

Bioaugmentation Anaerobic Digestion of Huangshui by Saccharomyces cerevisiae

by Xiaoying Zhang, Yujie Zhang, Zhaoyi Duan, Zhouying Liu, Bowen Xu, Ruixi Wang and Jishi Zhang

Fermentation 2026, 12(8), 375; https://doi.org/10.3390/fermentation12080375 - 9 Aug 2026

Viewed by 260

Abstract

Huangshui (HS) is rich in organic matter from Baijiu production. Anaerobic digestion (AD) of HS offers a hopeful strategy for efficient waste utilization and energy recovery. However, high organic load often causes low methane (CH₄) yield and process instability. The aim [...] Read more.

Huangshui (HS) is rich in organic matter from Baijiu production. Anaerobic digestion (AD) of HS offers a hopeful strategy for efficient waste utilization and energy recovery. However, high organic load often causes low methane (CH₄) yield and process instability. The aim of this study was to explore the mechanism of Saccharomyces cerevisiae (S. cerevisiae) to favor AD systems for more CH₄. And the results revealed that with an inoculation at 8% (v/v) addition of S. cerevisiae, CH₄ yield was 219.7 mL/g COD, representing a 20% increase compared to the control without S. cerevisiae. The main manifestation of augmentation was the increased bioavailability of dissolved organic compounds. In addition, the ethanol produced by S. cerevisiae under anaerobic conditions served as an electron donor to supply metabolic intermediates supporting methanogenesis, enriching Bacteroidetes_vadinHA17, Longilinea and Methanosaeta. This strategy promoted organic matter degradation and increased CH₄ yield, favoring the efforts of the industry to reduce pollution and carbon emissions. Full article

(This article belongs to the Section Industrial Fermentation)

► Show Figures

Figure 1

18 pages, 10527 KB

Open AccessArticle

Effects of Co-Fermentation with Saccharomyces cerevisiae and Lactobacillus plantarum on Volatile Flavor Compounds and Texture Properties of Duck Meat

by Sijia Chen, Lei Dong, Jia Guo, Runmei Zhang and Jun Cai

Fermentation 2026, 12(8), 374; https://doi.org/10.3390/fermentation12080374 - 9 Aug 2026

Viewed by 313

Abstract

This study investigated the changes in flavor and texture of duck meat during co-fermentation with Saccharomyces cerevisiae and Lactobacillus plantarum. Characteristic flavor compounds of duck meat, including hexanal, nonanal, octanal, (E)-2-octenal, and 1-octen-3-ol, were detected. With the extension of fermentation time, the [...] Read more.

This study investigated the changes in flavor and texture of duck meat during co-fermentation with Saccharomyces cerevisiae and Lactobacillus plantarum. Characteristic flavor compounds of duck meat, including hexanal, nonanal, octanal, (E)-2-octenal, and 1-octen-3-ol, were detected. With the extension of fermentation time, the variety and contents of alcohols, ketones, and esters increased. The contents of 1-hexanol, ethanol and 3-hydroxy-2-butanone increased from 0.24 ng/g, 0 ng/g and 0 ng/g prior to fermentation to 11.25 ng/g, 8.93 ng/g and 1.94 ng/g after fermentation. Respectively these compounds endow duck meat with intense fruity, alcoholic and creamy aromas. Meanwhile, the contents of compounds that produce a peculiar smell in duck meat, such as hexanal, heptanal, pentanal, and 1-octen-3-ol, decreased significantly. After fermentation, the hexanal content declined from 11.2 ng/g (before fermentation) to 2.7 ng/g, and the 1-octen-3-ol content decreased from 2.21 ng/g to 1.51 ng/g. Furthermore, under the interaction of S. cerevisiae and L. plantarum, the hardness of duck meat decreased from 1186.44 N to 561.48 N, and the chewiness decreased from 633.63 g to 167.16 g. These results demonstrate that co-fermentation with S. cerevisiae and L. plantarum is an effective approach to improve the flavor and quality of duck meat. This study provides a new strategy for the application of microbial fermentation in processing duck meat to enhance its flavor and quality. Full article

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

► Show Figures

Figure 1

12 pages, 787 KB

Open AccessArticle

Truncation of CYR1 Promoter in Baker’s Yeast to Improve Freeze Tolerance

by Xiaomeng Fu, Liangzi Zhang, Yong Wang, Jingru Zhou, Jingjing Xu and Kunqiang Hong

Fermentation 2026, 12(8), 373; https://doi.org/10.3390/fermentation12080373 - 9 Aug 2026

Viewed by 316

Abstract

Baker’s yeast with high freeze tolerance is essential for frozen-dough technology. The CYR1 gene, which encodes adenylate cyclase, is a central element of the cyclic adenosine monophosphate (cAMP) signaling pathway that regulates cellular stress tolerance. In this study, we aimed to enhance the [...] Read more.

Baker’s yeast with high freeze tolerance is essential for frozen-dough technology. The CYR1 gene, which encodes adenylate cyclase, is a central element of the cyclic adenosine monophosphate (cAMP) signaling pathway that regulates cellular stress tolerance. In this study, we aimed to enhance the freeze tolerance by modulating the expression level of CYR1. A series of diploid strains (BY14-30, BY14-60, BY14-90, and BY14-120) were constructed via a two-step integration method, in which the CYR1 promoter was truncated by 30, 60, 90, and 120 base pairs, respectively. Compared with the parent strain, strains BY14-30 and BY14-60 exhibited 4.3- and 4.2-fold higher survival rates after freezing, 60.0% and 40.0% increases in post-thaw dough-leavening ability, 88.9% and 64.6% increases in trehalose content, and 60.0% and 82.5% increases in proline levels, respectively. Collectively, our results demonstrate a novel strategy for regulating freeze tolerance in baker’s yeast, leading to improved cell viability and fermentation activity after freezing. Full article

(This article belongs to the Collection Yeast Biotechnology)

► Show Figures

Figure 1

21 pages, 2289 KB

Open AccessArticle

Bioconversion of Spent Green Tea Residues via Gamma Irradiation and Yeast Fermentation: Effects on Ruminal Fermentation, Degradability, and Methane Emissions

by Khalil Abid

Fermentation 2026, 12(8), 372; https://doi.org/10.3390/fermentation12080372 - 8 Aug 2026

Viewed by 274

Abstract

Spent green tea residues are an abundant lignocellulosic by-product that poses environmental disposal concerns, while its use in ruminant nutrition is constrained by low ruminal degradability associated with high fiber and phenolic contents. This study investigated the effects of gamma irradiation and solid-state [...] Read more.

Spent green tea residues are an abundant lignocellulosic by-product that poses environmental disposal concerns, while its use in ruminant nutrition is constrained by low ruminal degradability associated with high fiber and phenolic contents. This study investigated the effects of gamma irradiation and solid-state fermentation using Saccharomyces cerevisiae, and their combination, on chemical composition and ruminal fermentation. Gamma irradiation reduced neutral detergent fiber (379 to 336 mg g⁻¹ dry matter), acid detergent fiber (277 to 244 mg g⁻¹ dry matter), and total phenolics (89 to 75 mg gallic acid equivalents g⁻¹ dry matter) while increasing non-fiber carbohydrates (234 to 269 mg g⁻¹ dry matter) and ash (32 to 44 mg g⁻¹ dry matter). These modifications enhanced the gas production rate (3.26 to 3.37% h⁻¹), neutral detergent fiber degradability (38.9 to 46.1%), and the acetate-to-propionate ratio (2.25 to 2.43) while reducing ammonia nitrogen (108 to 96 mg L⁻¹), crude protein degradability (55.1 to 48.8%), and increasing rumen exoglycanase activity by 11% and xylanase activity by 15%. However, the methane proportion in total gas increased from 12.4 to 13.3% and methane yield per unit of degraded dry matter increased from 36.5 to 39.2 mL g⁻¹ degraded dry matter. Solid-state fermentation using Saccharomyces cerevisiae alone did not change the chemical composition or ruminal fermentation of non-irradiated biomass. However, when applied to irradiated biomass, it increased the crude protein from 320 to 383 mg g⁻¹ dry matter and ether extract from 31 to 49 mg g⁻¹ dry matter, improved dry matter degradability (53.3 to 63.1%), organic matter degradability (55.3 to 64.3%), crude protein degradability (48.8 to 54.6%), total volatile fatty acids (49 to 57 mmol L⁻¹), and net energy for lactation (2.43 to 3.02 MJ kg⁻¹ dry matter), and maintained ammonia nitrogen at levels similar to the irradiated biomass. Although the combined treatment increased the methane yield per unit of incubated dry matter (19.2 to 23.4 mL g⁻¹ dry matter), the methane yield per unit of degraded dry matter was lower than that of the irradiated biomass alone (37.0 vs. 39.2 mL g⁻¹ dry matter degraded) and comparable to the untreated control (36.5 mL g⁻¹ dry matter degraded). Overall, the integration of gamma irradiation as a pretreatment followed by solid-state fermentation with Saccharomyces cerevisiae enhances the nutritional value of spent green tea residues, supporting its valorization as a sustainable alternative ruminant feed resource. Full article

(This article belongs to the Special Issue Fermentations of Agri-Food By-Products for the Development of Functional Foods)

► Show Figures

Figure 1

26 pages, 757 KB

Open AccessArticle

Selection of Lactic Acid Bacteria Based on Antagonistic Activity and Mycotoxin Mitigation Capacity to Develop a Multistrain Consortium for Wheat Bran Fermentation

by Anara Yeleussizova, Modestas Ruzauskas, Gulnur Aliyeva, Saniya Tyshtykbayeva, Rita Šiugždinienė, Vytaute Starkute, Yablochkova Gulmira, Elena Bartkiene and Nurlan Kaumenov

Fermentation 2026, 12(8), 371; https://doi.org/10.3390/fermentation12080371 - 7 Aug 2026

Viewed by 408

Abstract

This study aimed to select lactic acid bacteria (LAB) strains based on their antagonistic activity and mycotoxin mitigation capacity, develop a biocompatible multistrain consortium, and evaluate its application for the fermentation of extruded wheat bran. The selected strains were assessed for biocompatibility, and [...] Read more.

This study aimed to select lactic acid bacteria (LAB) strains based on their antagonistic activity and mycotoxin mitigation capacity, develop a biocompatible multistrain consortium, and evaluate its application for the fermentation of extruded wheat bran. The selected strains were assessed for biocompatibility, and a four-strain consortium comprising Lacticaseibacillus casei, Levilactobacillus brevis, Pediococcus acidilactici, and Latilactobacillus curvatus was established. The consortium was propagated in supplemented sour whey and subsequently applied to wheat bran fermentation. Compared with the two-strain formulations, the four-strain consortium reduced the total bacterial count by 1.6-fold and the yeast and mold count by 1.75-fold after 36 h of fermentation. The consortium also produced the most pronounced acidification of the substrate, reducing the pH from 5.65 to 3.82 and increasing titratable acidity from 0.20 to 4.40 °N (22.0-fold). In contrast, fermentation with the two-strain formulations reduced the pH to 4.02 ± 0.01, while titratable acidity increased by 20.5–20.6-fold. After 36 h of fermentation, the viable LAB count in the substrate fermented with the four-strain consortium reached 7.23 ± 0.11 log₁₀ CFU/g, compared with 6.23 ± 0.02 and 6.42 ± 0.01 log₁₀ CFU/g in the substrates fermented with the two-strain formulations. These findings indicate that the developed four-strain consortium represents a promising starter culture for wheat bran fermentation and highlight its potential for the valorization of cereal by-products into value-added feed material through LAB fermentation. All experiments were conducted in vitro, and the effectiveness of the proposed approach under animal feeding conditions requires further experimental validation. Full article

(This article belongs to the Section Animal and Feed Fermentation)

► Show Figures

Figure 1

22 pages, 3894 KB

Open AccessArticle

Application of Resident Disease Screening Paradigm on Early Warning of Instability of Anaerobic Digestion of Food Waste

by Han Cheng, Xiangwei Li, Salma Tabassum and Hongbo Liu

Fermentation 2026, 12(8), 370; https://doi.org/10.3390/fermentation12080370 - 7 Aug 2026

Viewed by 333

Abstract

Early warning has been widely proven to be reliable in lowering the risk of instability for biological processes. However, it is very difficult for the warning systems used currently to achieve satisfactory accuracy, timeliness and universality simultaneously. This study developed a novel early [...] Read more.

Early warning has been widely proven to be reliable in lowering the risk of instability for biological processes. However, it is very difficult for the warning systems used currently to achieve satisfactory accuracy, timeliness and universality simultaneously. This study developed a novel early warning system for instability in food waste anaerobic digestion (FWAD) by bioimitating the human disease screening paradigm. It consists of single, comprehensive and microbiological indicators. Findings showed that single-factor early warning systems resembled acute patient diagnosis, having high accuracy but low timeliness and poor universality. Each of the chosen single indicators showed distinct early warning performances and clear preferences for diverse inhibitions concerning the instabilities of high organic load rate, high ammonia, and high fat in FWAD. Then, a new comprehensive indicator was developed using the entropy weights of several indicators. Confirmatory tests revealed that the comprehensive indicator-based early warning system was analogue to the resident sub-health diagnostic regarding superior foresight and good operability but poor targeting. Therefore, an early warning system based on microbial changes was proposed for potential instability in FWAD by bioimitating human periodic physical examination. The sensitive bacteria were identified as norank_o_ norank_c_Dojkabacteria and Rikenellaceae_RC9_gut_group. Enlarged tests showed that the developed system could be used for emergent, indistinct and potential early warnings simultaneously while avoiding the shortcomings of existing systems. More preciously, this study provided a paradigm for developing early warning systems of FWAD, which is also suitable to be applied to the intelligent systems that rely on automated machine learning. Full article

(This article belongs to the Special Issue Fermentation Processes: Modeling, Optimization and Control: 3rd Edition)

► Show Figures

Graphical abstract

29 pages, 16570 KB

Open AccessArticle

Enhanced Trehalose Production Through Integrated Chassis and Expression Engineering in Bacillus subtilis

by Jianghua Chen, Yujue Wang, Qiang Wang, Zhiming Rao and Xian Zhang

Fermentation 2026, 12(8), 369; https://doi.org/10.3390/fermentation12080369 - 6 Aug 2026

Viewed by 422

Abstract

Trehalose is a functional disaccharide widely used in the food, pharmaceutical, and cosmetic industries. It is industrially produced via a dual-enzyme process involving maltoligosaccharide trehalose synthase (MTSase) and maltoligosaccharide trehalose hydrolase (MTHase), with Escherichia coli (E. coli) serving as the expression [...] Read more.

Trehalose is a functional disaccharide widely used in the food, pharmaceutical, and cosmetic industries. It is industrially produced via a dual-enzyme process involving maltoligosaccharide trehalose synthase (MTSase) and maltoligosaccharide trehalose hydrolase (MTHase), with Escherichia coli (E. coli) serving as the expression host. Bacillus subtilis (B. subtilis) is an ideal host for industrial trehalose production due to its generally recognized as safe (GRAS) status and low phage susceptibility. However, engineered B. subtilis strains often exhibit slow growth, low heterologous protein expression, and high fermentation costs, thereby limiting their industrial application. To address these challenges, this study employed a synergistic strategy that combined chassis modification, expression element optimization, and knockout of substrate-competition pathways. First, a tryptophan-independent strain was constructed by reverting the trpC2 mutation to shorten the growth cycle. Next, knockout of flgD, yueB, and integration of E. coli-derived glutamate dehydrogenase (gdhA) significantly enhanced biomass accumulation. Expression of MTSase and MTHase was markedly improved through tandem strong promoters (P_HpaII-P₃₆) and ribosome-binding site (RBS) optimization (RBS1), achieving a 10.87-fold and 4.22-fold increase in enzyme activity, respectively. Finally, disruption of the amyE gene reduced non-specific substrate degradation. Using maltodextrin as substrate, the final trehalose conversion rate reached 76%. This study constructed B. subtilis chassis cells that highly express MTHase and MTSase respectively, laying a foundation for subsequent industrial trehalose production. Full article

(This article belongs to the Special Issue Applied Microorganisms and Industrial/Food Enzymes, 3rd Edition)

► Show Figures

Figure 1

19 pages, 2237 KB

Open AccessArticle

Upcycling Jackfruit Seeds as a Sustainable Malt Substitute for Beer Fermentation: Impacts on Physicochemical Quality and Volatile Profile

by Nyan Minn Paing, Witsaponr Jorsungnoen, Sumittra Thaingoea, Shankar Neupane, Do Quyen Nguyen and Nattaya Konsue

Fermentation 2026, 12(8), 368; https://doi.org/10.3390/fermentation12080368 - 6 Aug 2026

Viewed by 354

Abstract

Jackfruit seeds (JFSs) are an underutilized agro-industrial by-product with considerable nutritional and functional potential for sustainable food fermentation. This study evaluated the feasibility of using jackfruit seed flour as a partial malt substitute in beer brewing at replacement levels of 0%, 25%, 50%, [...] Read more.

Jackfruit seeds (JFSs) are an underutilized agro-industrial by-product with considerable nutritional and functional potential for sustainable food fermentation. This study evaluated the feasibility of using jackfruit seed flour as a partial malt substitute in beer brewing at replacement levels of 0%, 25%, 50%, and 75% (w/w). Fresh jackfruit seeds were processed into flour, gelatinized, and mashed with pale ale malt in the presence of α-amylase before fermentation with Saccharomyces cerevisiae, Lutra kveik ale yeast. The physicochemical properties of the raw materials, starch hydrolysis during mashing, beer quality attributes, and volatile aroma compounds were investigated. Compared with pale ale malt, JFS contained higher crude protein (13.22%), total phenolic content (476.66 mg GAE/100 g), and antioxidant activity. HPLC-IR analysis demonstrated the formation of fermentable sugars during mashing, although starch conversion from JFS remained incomplete at higher substitution levels. Increasing JFS substitution significantly enhanced beer foamability (up to 142.22%) and foam stability (112.84 s), which was attributed to the higher protein content of the seeds. However, beers containing higher proportions of JFS exhibited darker color and increased turbidity, reaching 680 NTU at 75% substitution. HS-SPME-GC-MS analysis revealed changes in alcohols, esters, and ketones with increasing JFS substitution. These findings demonstrate that jackfruit seed flour can serve as a sustainable malt adjunct for beer production, improving selected quality attributes while valorizing agricultural by-products. The study highlights the potential of jackfruit seeds as a functional brewing ingredient that supports the development of sustainable and next-generation fermented beverages. Full article

(This article belongs to the Special Issue Microbial Fermentation: A Sustainable Approach to Food Production)

► Show Figures

Figure 1

15 pages, 785 KB

Open AccessArticle

Identification of Lactic Acid Bacteria Isolated from Sourdoughs Produced with Flours of Different Cereals in North-Western Spain via MALDI-TOF MS and pheS Gene Analyses

by Lorena Celador-Lera, Rosana Chiva, Ana Jiménez-López, Fernando Sánchez-Juanes, José Antonio Uña, Raúl Rivas, María Ángeles Santos, Encarna Velázquez and Mercedes Tamame

Fermentation 2026, 12(8), 367; https://doi.org/10.3390/fermentation12080367 - 6 Aug 2026

Viewed by 396

Abstract

Lactic acid bacteria (LAB) are Gram-positive cocci or rods from different genera and species that synergistically coexist with yeasts in cereal sourdoughs. Although the production and consumption of sourdough breads have increased in the last decade, there are still few studies that identify [...] Read more.

Lactic acid bacteria (LAB) are Gram-positive cocci or rods from different genera and species that synergistically coexist with yeasts in cereal sourdoughs. Although the production and consumption of sourdough breads have increased in the last decade, there are still few studies that identify the LABs present in sourdoughs of different origins. In this study, we identified LAB strains isolated from wheat sourdoughs sourced from bakeries in north-western Spain and from experimental sourdoughs developed by a baker with four different cereal flours: wheat, rye, spelt, and tritordeum. Through a combination of MALDI-TOF and pheS gene sequence analyses, we identified Lactiplantibacillus plantarum and Levilactobacillus brevis in all analysed sourdoughs. Moreover, Lactiplantibacillus paraplantarum, Lacticaseibacillus paracasei, Lactococcus lactis, Pediococcus pentosaceus, and Weissella paramesenteroides were identified in different sourdoughs. These species were also isolated from sourdoughs obtained in other European countries, although we did not identify the other LAB genera identified in some of them. Our results demonstrate the need to identify the LAB species from sourdoughs of different origins prior to designing suitable starters for inoculated sourdoughs, particularly those produced with innovative flours. To our knowledge, this is the first report on the identity of LABs present in tritordeum sourdoughs in Spain. Full article

(This article belongs to the Special Issue Fermented Cereals and Legumes: Innovation for the Development and Characterization of Functional Foods)

► Show Figures

Graphical abstract

38 pages, 2240 KB

Open AccessReview

Xylitol Biomanufacturing: Production Technologies, Industrial Applications and Future Opportunities

by Yanjie Jia, Wanting Yang, Lulu Zhang, Xinkang Hu, Huanhuan Zhang and Bo Zhang

Fermentation 2026, 12(8), 366; https://doi.org/10.3390/fermentation12080366 - 5 Aug 2026

Cited by 1 | Viewed by 500 | Correction

Abstract

Xylitol is a five-carbon sugar alcohol widely used in the food, pharmaceutical, oral healthcare, and personal care industries because of its low caloric value, low glycaemic index, and non-cariogenic properties. Industrial production is mainly based on catalytic hydrogenation of xylose, which provides high [...] Read more.

Xylitol is a five-carbon sugar alcohol widely used in the food, pharmaceutical, oral healthcare, and personal care industries because of its low caloric value, low glycaemic index, and non-cariogenic properties. Industrial production is mainly based on catalytic hydrogenation of xylose, which provides high conversion efficiency but requires intensive energy input, costly catalysts, and complex purification processes. Microbial fermentation has emerged as a sustainable alternative for producing xylitol from renewable lignocellulosic biomass. This review summarizes recent advances in xylitol production, with a particular focus on microbial biomanufacturing. Key developments in lignocellulosic biomass utilization, metabolic engineering, cofactor balancing, oxygen regulation, and fermentation optimization are discussed. Chemical and biological production routes are critically compared in terms of efficiency, sustainability, and industrial applicability. Recent progress in downstream purification and biorefinery integration is also highlighted. Despite substantial advances, challenges including inhibitor toxicity, limited microbial robustness, low fermentation productivity, and high purification costs continue to hinder large-scale commercialization. Future research should focus on feedstock valorization, systems metabolic engineering, process intensification, and sustainable separation technologies to improve the economic and environmental sustainability of bio-based xylitol production. Full article

(This article belongs to the Special Issue Production of Added-Value Metabolites Through Microbial Fermentation)

► Show Figures

Graphical abstract

16 pages, 2789 KB

Open AccessArticle

pH-Regulated Acidogenic Fermentation of Chicken Manure Promotes Lactic Acid and Acetic Acid Production While Limiting Nitrogen Release

by Tongxin Xue, Jiahao Zhang, Yapeng Song, Ahmed Mahdy and Wei Qiao

Fermentation 2026, 12(8), 365; https://doi.org/10.3390/fermentation12080365 - 4 Aug 2026

Viewed by 275

Abstract

Acidogenic fermentation offers a promising approach to convert chicken manure into carbon-rich liquid products for various practical applications. However, the high nitrogen content in chicken manure hinders acidogenesis and limits product utilization due to ammonium accumulation. To address this, a 320-day fermentation experiment [...] Read more.

Acidogenic fermentation offers a promising approach to convert chicken manure into carbon-rich liquid products for various practical applications. However, the high nitrogen content in chicken manure hinders acidogenesis and limits product utilization due to ammonium accumulation. To address this, a 320-day fermentation experiment was conducted in a two-stage operation (Stage I: uncontrolled pH; Stage II: pH controlled at 5.0). pH adjustment was conducted by adding HCl. The continuously stirred tank fermentation reactor was operated at 37 °C and manually fed daily. Results showed that pH adjustment shifted the metabolic pathway from volatile fatty acid (VFA)-dominated production to lactic acid-enriched production: lactic acid increased from 12.6 to 35.7 g-COD/L, total VFAs decreased by 58%, while acetic acid remained at a relatively high level of chemical oxygen demand (COD) of 17.6 gCOD/L. Total ammonia nitrogen (TAN) decreased from 7.0 to 3.1 g/L, increasing the ratio of soluble COD (SCOD) to TAN from 19:1 to 38:1. The ammonium reduction was primarily due to selective inhibition of uric acid degradation under low pH, while protein hydrolysis remained largely unaffected. These findings demonstrate the potential of pH-regulated chicken manure fermentation liquor as a high-value product. Full article

(This article belongs to the Special Issue Waste and Wastewater Biotreatment for Bioenergy and Bioresource Recovery)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Fermentation, Volume 12, Issue 8 (August 2026) – 54 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI