Fermentation

24 pages, 8133 KB

Open AccessReview

The Microbial Palette: From Bioprospecting to Genetic Engineering of Microbial Pigments

by Bruna Lise Tusset, Iago Mocelin, Lorenza Corti Villa, Alice Elvira Teixeira dos Santos, Rafael de Matos, Lívia Kmetzsch and Fernanda Cortez Lopes

Fermentation 2026, 12(6), 263; https://doi.org/10.3390/fermentation12060263 - 28 May 2026

Abstract

Microbial pigments are secondary metabolites that represent promising alternatives to synthetic colorants, offering advantages even over other natural sources. These pigments can be produced independently of seasonality and at low cost, especially when using agro-industrial residues as substrates, and their production can be [...] Read more.

Microbial pigments are secondary metabolites that represent promising alternatives to synthetic colorants, offering advantages even over other natural sources. These pigments can be produced independently of seasonality and at low cost, especially when using agro-industrial residues as substrates, and their production can be optimized. Bioprospecting of microorganisms in unexplored environments offers valuable opportunities to discover safer and more efficient pigment producers. Brazil harbors vast biodiversity across multiple biomes, providing a rich reservoir for such discoveries. Biomes such as the Atlantic Forest, Pampa, Pantanal and Coastal Marine are still poorly explored with respect to the bioprospecting of pigment-producing microorganisms, representing a valuable opportunity for the discovery of novel pigments. However, several bottlenecks still hinder the regulatory approval of microbial pigments, particularly those produced by filamentous fungi, due to the frequent co-production of mycotoxins. To overcome these challenges, genetic engineering tools are crucial for eliminating mycotoxin co-production. CRISPR-Cas9, CRISPRi and CRISPR-Cpf1 have become the most widely used techniques for this purpose. Another key application of CRISPR is the enhancement of pigment yields, which can accelerate the industrial adoption of microbial pigments. Together, these two strategies, bioprospecting new environments and genetic engineering, can significantly speed up the transition from synthetic pigments to safer and more eco-friendly microbial alternatives. Full article

(This article belongs to the Special Issue Bioprospecting Pigment-Producing Microorganisms from Different Biomes)

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26 pages, 474 KB

Open AccessReview

The Challenge of Using Non-Saccharomyces Yeasts in Brewing: The Impact of Τorulaspora delbrueckii

by Fotini Drosou, Panagiotis Tataridis, Vassilis G. Dourtoglou and Vassiliki Oreopoulou

Fermentation 2026, 12(6), 262; https://doi.org/10.3390/fermentation12060262 - 27 May 2026

Abstract

Yeasts are among the intrinsic factors affecting the quality of beer due to their impact on flavor. Apart from a long and rich brewing tradition of natural fermentations, involving different yeast and bacterial species in regions such as Belgium, non-Saccharomyces yeasts have [...] Read more.

Yeasts are among the intrinsic factors affecting the quality of beer due to their impact on flavor. Apart from a long and rich brewing tradition of natural fermentations, involving different yeast and bacterial species in regions such as Belgium, non-Saccharomyces yeasts have not been the preferred industrial inoculation strains in both winemaking and brewing sectors. This is mainly due to their slower fermentation rates, lower alcohol tolerance, and limited ability to complete fermentation. This review explores the brewing characteristics of Torulaspora delbrueckii strains, focusing on the aromatic profile of the produced beers, in comparison with the well-known Saccharomyces cerevisiae brewing strains. The effect of fermentation parameters, as well as the use of mono- and mixed cultures with S. cerevisiae, is discussed. Specific T. delbrueckii strains have demonstrated the ability to ferment wort sugars and produce alcohol levels of up to 4–6% (v/v). The main volatile compounds produced include higher alcohols, such as isoamyl and phenyl ethyl alcohol, as well as esters and their acid precursors. Among these, ethyl hexanoate and ethyl octanoate are particularly important due to their contribution to fruity aromas. Mixed fermentations involving T. delbrueckii and S. cerevisiae have been shown to enhance ester production, resulting in improved aromatic complexity in the final product. Full article

(This article belongs to the Section Yeast)

2 pages, 141 KB

Open AccessEditorial

Fermentation and Biotechnology in Wine Making

by Manuel Malfeito-Ferreira

Fermentation 2026, 12(6), 261; https://doi.org/10.3390/fermentation12060261 - 27 May 2026

Abstract

The winemaking sector is currently experiencing a period of deep transformation, driven by the convergence of traditional oenological knowledge with advances in biotechnology, microbial ecology, analytical chemistry, and sustainable production systems [...] Full article

(This article belongs to the Special Issue Fermentation and Biotechnology in Wine Making)

18 pages, 10670 KB

Open AccessArticle

Investigating the Bacteriostatic Activity and Bactericidal Mechanism of Bacteriocin-like YY-1 Produced by Latilactobacillus sakei W-1 Against Escherichia coli

by Xinyue Wang, Yuhang Zheng, Xinyu Wang, Boran Zhang, Wanli Sha, Wenlong Dong and Baishuang Yin

Fermentation 2026, 12(6), 260; https://doi.org/10.3390/fermentation12060260 - 26 May 2026

Abstract

Research has demonstrated that the presence of synthetic preservatives tends to disrupt the balance of the gut microbiota, thereby posing a significant threat to food safety and human health. The present study investigates the antibacterial activity of a novel bacteriocin-like produced by Latilactobacillus [...] Read more.

Research has demonstrated that the presence of synthetic preservatives tends to disrupt the balance of the gut microbiota, thereby posing a significant threat to food safety and human health. The present study investigates the antibacterial activity of a novel bacteriocin-like produced by Latilactobacillus sakei (L. sakei) against Escherichia coli (E. coli), as well as its mechanism of action. This study aims to validate the significant antibacterial effect of bacteriocin-like YY-1 produced by L. sakei W-1 through dialysis combined with Tricine-SDS-PAGE analysis, and to determine its molecular weight. The results of the study indicate that the molecular weight of the bacteriocin-like is less than 2.7 kDa. Moreover, this bacteriocin-like YY-1 exhibits broad-spectrum antimicrobial properties, demonstrating antibacterial activity against E. coli, S. Typhimurium, A. baumannii, P. mirabilis, S. aureus, L. monocytogenes. Furthermore, bacteriocin-like YY-1 exhibits optimal antibacterial activity at a pH of 4.0, with its activity gradually diminishing as pH increases. It is completely inactivated by trypsin treatment, while papain and proteinase K treatments significantly reduce its antibacterial activity. Additionally, this bacteriocin-like YY-1 has been demonstrated to inhibit the growth of E. coli and disrupt its normal development. The Viable/Necrotic Cell Stain and SEM observations confirmed that the bacteriocin-like compound induces cell death by forming distinct pores through the disruption of the cell membrane’s structural integrity. In summary, YY-1—a bacteriocin-like substance characterised by its low molecular weight (<2.7 kDa), broad-spectrum activity, and pore-forming mechanism—is a highly promising natural alternative to synthetic preservatives, capable of mitigating the damage caused by chemical additives to the gut microbiota. Full article

(This article belongs to the Special Issue Probiotic Lactic Acid Bacteria and Their Applications in Food Safety and Animal Health)

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24 pages, 834 KB

Open AccessReview

Improvement in Crop Growth and Quality with Anaerobic Digestate: Application Benefits and Future Prospects

by Faqinwei Li, Zheng Wang, Chaoyang Wei, Qiuhui Li, Naoto Shimizu and Yongheng Yuan

Fermentation 2026, 12(6), 259; https://doi.org/10.3390/fermentation12060259 - 26 May 2026

Abstract

The overuse of mineral fertilizers has brought about numerous matters such as deteriorating soil health, crop safety concerns, and environmental pollution. The global requirements for effective waste handling and sustainable agricultural production have been growing continuously. Therefore, integrated nutrient management method might be [...] Read more.

The overuse of mineral fertilizers has brought about numerous matters such as deteriorating soil health, crop safety concerns, and environmental pollution. The global requirements for effective waste handling and sustainable agricultural production have been growing continuously. Therefore, integrated nutrient management method might be a key way to achieve circular agriculture, such as replacing chemical fertilizers with organic fertilizers. In modern agriculture, digestate that is a byproduct of anaerobic digestion as a fertilizer is becoming increasingly favored as a viable method for improving crop yield and quality. However, the application of digestate in agriculture have not yet been fully explored. This review addresses a knowledge gap by synthesizing current research on digestate as a fertilizer. Firstly, the physical–chemical and biological properties of digestate are discussed. Following that, this review focuses on its specific impact on crop growth and quality. Lastly, it outlines the challenges faced in the application of digestate and looks ahead to future trends. With appropriate policy support and technological innovation, digestate holds promise for advancing environmental sustainability. This review aims to provide direction and reference for future research on the application of digestate. Full article

(This article belongs to the Special Issue Anaerobic Digestion to High-Value Organic Fertilizer and Biogas)

16 pages, 3438 KB

Open AccessArticle

Regulatory Mechanisms of Issatchenkia orientalis Y1 on Microbial Community Assembly and Potential Functions in Fermented Grains of Strong-Flavor Baijiu

by Jingxin Jiang, Mingyao Wang, Huibo Luo and Dan Huang

Fermentation 2026, 12(6), 258; https://doi.org/10.3390/fermentation12060258 - 26 May 2026

Abstract

Issatchenkia orientalis Y1 is an important functional microorganism during the fermentation of strong-flavor Baijiu and may influence microbial community structure, community assembly mechanisms, and microbial functional potential predicted from sequencing data. In this study, a mixed-culture fermentation system was established using fermented grains [...] Read more.

Issatchenkia orientalis Y1 is an important functional microorganism during the fermentation of strong-flavor Baijiu and may influence microbial community structure, community assembly mechanisms, and microbial functional potential predicted from sequencing data. In this study, a mixed-culture fermentation system was established using fermented grains and Huangshui from strong-flavor Baijiu production. I. orientalis Y1, isolated from fermented grains, was inoculated into this system as a perturbation treatment to investigate its effects on microbial diversity, community composition, and functional profiles, as well as its influence on microbial community assembly pathways. The results showed that inoculation with I. orientalis Y1 significantly altered microbial diversity and increased community complexity. The relative abundances of Paenibacillus, Aspergillus, and Acetobacter decreased, with the peak abundance of Paenibacillus declining from 62.8% to 40.2% and that of Acetobacter decreasing from 27.8% to 19.1%, while Aspergillus remained consistently less abundant than in the control group throughout fermentation. In contrast, the relative abundances of Issatchenkia and Lactobacillus increased, with their peak abundances rising from 15.0% to 23.9% and from 7.6% to 27.0%, respectively. In addition, it increased the contribution of deterministic processes in community assembly, with the deterministic proportion rising from 31.1% to 35.5% in bacterial communities and from 28.4% to 48.8% in fungal communities, while the contribution of stochastic processes decreased. These changes suggest that the microbial community became more controllable and functionally more stable after inoculation. Meanwhile, the overall predicted metabolic activity of the microbial community declined. In conclusion, the addition of I. orientalis Y1 reshaped microbial community structure, influenced microbial community assembly processes, and altered the correlations between dominant microorganisms and metabolic pathways. Full article

(This article belongs to the Special Issue Advances in Fermented Foods and Beverages, 2nd Edition)

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22 pages, 1938 KB

Open AccessArticle

Sustainable Bioethanol Production from Cocoa Pod Husk with and Without Reductive Catalytic Fractionation (RCF)

by Sebastian Andrade, Claudia García, Samanta Iturralde, Jorge Delgado-Noboa, Verónica Pinos-Vélez, Mónica Abril-González and Angelica Vele-Salto

Fermentation 2026, 12(6), 257; https://doi.org/10.3390/fermentation12060257 - 25 May 2026

Abstract

The urgent need to reduce greenhouse gas emissions has driven the search for sustainable alternatives to fossil fuels. In this context, cocoa residues emerge as a promising feedstock for bioethanol production. This study evaluated the influence of a catalytic biorefinery treatment on the [...] Read more.

The urgent need to reduce greenhouse gas emissions has driven the search for sustainable alternatives to fossil fuels. In this context, cocoa residues emerge as a promising feedstock for bioethanol production. This study evaluated the influence of a catalytic biorefinery treatment on the bioethanol production potential from cocoa pod husks. Both raw and catalytically treated biomass were characterized using SEM, pore size distribution analysis, and TGA. Subsequently, enzymatic hydrolysis was performed using various cellulase and hemicellulase loadings, followed by anaerobic fermentation with Saccharomyces cerevisiae. Bioethanol production was modeled using the modified Gompertz equation. The results evidenced changes in the structure and composition of the lignocellulosic matrix following catalytic treatment, increasing surface area and reducing hemicellulose content. Although total sugar release during hydrolysis was comparable between the two samples, the biomass processed via the catalytic biorefinery promoted higher sugar consumption and bioethanol concentration, reaching 3.36 g/L with a yield of 112 g kg⁻¹ of dry biomass. The kinetic model showed a strong fit (R² between 0.94 and 0.97). These findings demonstrate that the integration of catalytic biorefinery, enzymatic hydrolysis, and fermentation constitutes a viable alternative for the valorization of cocoa residues. Full article

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

23 pages, 1442 KB

Open AccessArticle

Effects of Sorghum–Sudangrass Hybrid Varieties on Silage Fermentation Quality and Bacterial Community Structure

by Weiqiang Song, He Dong, Xingzhao Zhou, Sen Zong, Xinyu Liu, Zhiyong Tian, Jiakun Du, Yulin Li, Xun Chen, Wenge Li, Meiling Hou and Yanzi Xiao

Fermentation 2026, 12(6), 256; https://doi.org/10.3390/fermentation12060256 - 25 May 2026

Abstract

This study aimed to screen high-yield and high-quality sorghum–sudangrass hybrid varieties suitable for popularization and cultivation in the Hulunbuir region through a comprehensive evaluation of silage fermentation quality and bacterial community. Comparative analyses were conducted on six sorghum–sudangrass varieties, namely, sorghum–sudangrass hybrid 3 [...] Read more.

This study aimed to screen high-yield and high-quality sorghum–sudangrass hybrid varieties suitable for popularization and cultivation in the Hulunbuir region through a comprehensive evaluation of silage fermentation quality and bacterial community. Comparative analyses were conducted on six sorghum–sudangrass varieties, namely, sorghum–sudangrass hybrid 3 (SS1), sorghum–sudangrass hybrid 4 (SS2), sorghum–sudangrass hybrid 5 (SS3), sorghum–sudangrass hybrid 7 (SS4), sorghum–sudangrass hybrid 8 (SS5), and Super Sugar–Dwarf Sorghum (SS6). The harvested sorghum–sudangrass at the late milk stage was chopped, vacuum-sealed in polyethylene bags (30 cm × 40 cm), and subjected to 60 days of ensiling fermentation. The results revealed significant differences among different varieties (p < 0.05). SS2 achieved the highest fresh herbage yield of 78.26 t/hm², while the fresh yield of SS4 was 57.39 t/hm², approximately 26.7% lower than that of SS2. However, SS4 exhibited superior quality, with the thickest stem diameter of 20.26 mm (p < 0.05). It exhibited the highest crude protein content, reaching 5.72% DM; its silage pH was relatively low, at only 3.71 (p < 0.05); its fiber content was significantly reduced (acid detergent fiber, ADF = 40.03% DM, p < 0.05); and it was rich in Lactococcus and Lactobacillus (p < 0.05). The ensiling process of SS4 highly significantly decreased bacterial diversity (p < 0.01) and shifted the dominant bacterial phylum from Proteobacteria to Firmicutes. Functional prediction indicated that the bacterial community of SS2 possessed the highest predicted abundance of functional genes related to cellulase and beta-glucosidase (p < 0.05). Our findings suggest that SS2 should be prioritized for production systems aiming for maximum biomass accumulation, whereas SS4 is recommended as a superior variety for high-quality animal nutrition systems where fermentation stability and nutrient preservation are paramount. Full article

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

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21 pages, 8487 KB

Open AccessArticle

Scale-Up of a Two-Stage Anaerobic Digestion System: From Laboratory Reactor to Pilot Plant

by Maria Isabella Lima Garção, Joachim Müller and Andreas Lemmer

Fermentation 2026, 12(6), 255; https://doi.org/10.3390/fermentation12060255 - 24 May 2026

Abstract

Two-stage anaerobic digestion systems are extensively researched for enhancing process stability and phase separation when processing complex organic materials. Scaling from laboratory setups to pilot plants necessitates engineering modifications to ensure operational feasibility. In this study, a laboratory-scale system comprising a 100 L [...] Read more.

Two-stage anaerobic digestion systems are extensively researched for enhancing process stability and phase separation when processing complex organic materials. Scaling from laboratory setups to pilot plants necessitates engineering modifications to ensure operational feasibility. In this study, a laboratory-scale system comprising a 100 L horizontal CSTR and a packed-bed reactor was scaled up 100-fold. The design separates solid and liquid retention times, with fibers retained in the first stage while liquids and volatile fatty acids flow into the second. Fiber retention in the lab was achieved using a 100 µm sieve dividing the CSTR into two chambers, allowing prolonged lignocellulosic degradation. During scale-up, a filtration and recirculation system was introduced, able to return the fibers to the first reactor through a 1000 µm edge-gap filter, which separates liquids for the second reactor and recycles undegraded fibers. An economic analysis indicated a scale-up exponent of 0.396, indicating that unit costs decrease with plant size and demonstrating economies of scale. Laboratory-based mass balance estimates biogas production at approximately 16.3 m³ daily at the pilot scale, equivalent to 90 kWh. The modular system aims to be transferred to small farms, promoting cost-effective biogas from manure and local residues to support decentralized renewable energy in agriculture. Full article

(This article belongs to the Special Issue Application of Anaerobic Digestion Technology: Current Progress and New Trends)

18 pages, 699 KB

Open AccessArticle

Orange-Peel Waste Enzymatic Saccharification: Scaling-Up Under Diverse pH-Control Strategies

by Ramón J. Ceballos-Zúñiga and Miguel Ladero

Fermentation 2026, 12(6), 254; https://doi.org/10.3390/fermentation12060254 - 24 May 2026

Abstract

Waste from the fruit juice industry presents high sugar and phenolic contents, high humidity and biological activities and cumbersome disposal or low-added valorization. Orange-peel waste (OPW) represents 35–55% w/w of processed fruit, with oranges being the main citric crop. OPW saccharification [...] Read more.

Waste from the fruit juice industry presents high sugar and phenolic contents, high humidity and biological activities and cumbersome disposal or low-added valorization. Orange-peel waste (OPW) represents 35–55% w/w of processed fruit, with oranges being the main citric crop. OPW saccharification leads to sugar-rich hydrolysates that can be further processed via fermentative and catalytic routes. In this work, OPW enzymatic hydrolysis was studied via batch and fed-batch processing using either a 50 mM citrate buffer or a 9 g/L NaCl solution with pH control by adding CaCO₃ to ensure high enzyme activity across the enzymatic process. Preliminary runs showed that particle size of 3.4 mm diameter and a 300 r.p.m. stirring speed, a six-blade Rushton turbine and wall baffles were adequate to reach high sugar yields in batch. Further scale-up in batch at medium solid loading (12.5% w/w) and fed-batch operation at high-solid loading (20% w/w) led to high yields and glucose and fermentable sugars (up to 74 and 136 g/L, respectively, when using the saline solution and CaCO₃ as pH-controlling agent, in only 50 h; notably shorter and higher than when using the citrate buffer). Fractal kinetic models have been shown to accurately represent the compositional change across all batch and fed-batch conditions, highlighting NaCl reaction medium and alkali-driven pH control as the most appropriate approach to achieve high yields at low process times, a promising result for further developments at demonstration and industrial scales using automatic pH control. Full article

(This article belongs to the Special Issue 10th Anniversary of Fermentation: Feature Papers in the “Fermentation Process Design” Section)

13 pages, 3286 KB

Open AccessArticle

Different Concentrations of Copaiba Oil (Copaifera spp.) in Ruminal Fermentation

by Anderson Luiz de Lucca Bento, Raizza Fátima A. Tulux Rocha, Marcelo Vedovatto, Jocely Gomes de Souza, Fábio José Carvalho Faria, Luís Carlos Vinhas Ítavo, Anuzhia Paiva Moreira, Andréa Roberto D. Lopes Souza and Gumercindo Loriano Franco

Fermentation 2026, 12(6), 253; https://doi.org/10.3390/fermentation12060253 - 24 May 2026

Abstract

The use of copaiba oil (COP) in ruminant nutrition is relatively recent, and the results reported in the literature remain controversial. This study evaluated the effects of increasing dietary concentrations of COP on ruminal fermentation in steers. Five rumen-cannulated steers were assigned to [...] Read more.

The use of copaiba oil (COP) in ruminant nutrition is relatively recent, and the results reported in the literature remain controversial. This study evaluated the effects of increasing dietary concentrations of COP on ruminal fermentation in steers. Five rumen-cannulated steers were assigned to a 5 × 5 Latin square design and received the following treatments: Control (0 g kg⁻¹ of COP), 1.25 g kg⁻¹ COP, 2.50 g kg⁻¹ COP, and 3.75 g kg⁻¹ COP dry matter (DM), and monensin (positive control; 40 mg kg⁻¹ DM in the concentrate). Animals were fed a 50:50 forage:concentrate diet. Copaiba oil supplementation (1.25 to 3.75 g kg⁻¹ DM) did not affect ruminal pH, the concentrations of NH₃-N, or propionate (mmol L⁻¹; p > 0.05). Similarly, COP had no effect on intake or nutrient digestibility (p > 0.05). In contrast, monensin increased (p ≤ 0.05) the concentrations of NH₃-N and propionate (mmol L⁻¹). Overall, COP supplementation did not modify ruminal fermentation under the conditions of this study. However, further studies are needed to assess its effects in diets with higher forage proportions, which better represent grazing systems. Full article

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

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24 pages, 3732 KB

Open AccessArticle

Humification and Bacterial Community Changes During Sludge Composting with Copper/Iron-Based Fenton-like Treatments

by Ruicheng Mao, Quanmin Sun, Zexin Xie, Yifa Wang, Fang Luo, Xiangmeng Ma and Zhanbo Hu

Fermentation 2026, 12(6), 252; https://doi.org/10.3390/fermentation12060252 - 22 May 2026

Abstract

Insufficient oxidative capacity can limit humification during municipal sludge composting. This study comparatively evaluated two Fenton-like amendment systems, a homogeneous copper-based treatment (CH) and a heterogeneous nano-iron-based treatment (NFH), for their effects on composting performance, humification-related indices, spectroscopic characteristics, and bacterial community succession. [...] Read more.

Insufficient oxidative capacity can limit humification during municipal sludge composting. This study comparatively evaluated two Fenton-like amendment systems, a homogeneous copper-based treatment (CH) and a heterogeneous nano-iron-based treatment (NFH), for their effects on composting performance, humification-related indices, spectroscopic characteristics, and bacterial community succession. Both amended treatments improved composting performance relative to the control, reaching higher peak temperatures (68.5 °C for CH and 70.3 °C for NFH) and prolonging the thermophilic phase. NFH also showed stronger moisture removal, with the final moisture content decreasing to 58.1%, compared with 65.1% in CH and 64.1% in the control. CH showed the highest apparent humic acid accumulation (1173 mg kg⁻¹), whereas NFH exhibited spectroscopic features commonly associated with lower E₄/E₆ ratios and more pronounced humic-like fluorescence characteristics. Ultraviolet–visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), and excitation–emission matrix fluorescence spectroscopy (EEM) analyses collectively indicated progressive transformation toward more aromatic and humified organic matter in the amended treatments. Bacterial community succession also differed across treatments, and several enriched taxa, including Rhodanobacter and Thermobifida, showed positive associations with reactive oxygen species (ROS)-related variables and humification indices. These results describe treatment-linked dynamics in humification and suggest corresponding changes in microbial succession during sludge composting, with potential implications for process outcomes. Full article

(This article belongs to the Section Industrial Fermentation)

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4 pages, 133 KB

Open AccessEditorial

Development and Application of Starter Cultures, 2nd Edition

by Roberta Comunian and Luigi Chessa

Fermentation 2026, 12(6), 251; https://doi.org/10.3390/fermentation12060251 - 22 May 2026

Abstract

The growing demand to harmonize food safety with preservation of autochthonous sensory phenotypes has catalyzed a paradigm shift in starter culture microbiology [...] Full article

(This article belongs to the Special Issue Development and Application of Starter Cultures, 2nd Edition)

23 pages, 4206 KB

Open AccessArticle

Polyhydroxyalkanoate Production by Gordonia lacunae BS2^T in Hydrolysates of Canola Fines

by Pamela J. Welz, Amrita Ranjan, Thandekile Mthethwa and Marilize le Roes-Hill

Fermentation 2026, 12(5), 250; https://doi.org/10.3390/fermentation12050250 - 21 May 2026

Abstract

Microbial polyhydroxyalkanoates (PHAs) are biodegradable biopolymers that are gaining traction as replacements for conventional petroleum-based plastics. In this study, sugar utilization, growth and polyhydroxybutyrate (PHB) and polyhdroxyvalerate (PHV) production in synthetic and real hydrolysates of Canola fines (SHCF, RHCF) by Gordonia lacunae BS2 [...] Read more.

Microbial polyhydroxyalkanoates (PHAs) are biodegradable biopolymers that are gaining traction as replacements for conventional petroleum-based plastics. In this study, sugar utilization, growth and polyhydroxybutyrate (PHB) and polyhdroxyvalerate (PHV) production in synthetic and real hydrolysates of Canola fines (SHCF, RHCF) by Gordonia lacunae BS2^T were evaluated: (i) in SHCF under different C:N ratios and O₂ availability, and (ii) in SHCF and RHCF (50% and 100%) under shaking v/s static conditions with limited or non-limited O₂. The bacterium was able to utilize glucose, cellobiose, arabinose, and xylose. Athough O₂ limitation reduced growth, higher measured concentrations of 3-hydroxyvalerate (3HV) were achieved under O₂ limitation, translating into slightly higher 3-hydroxybutyrate (3HB)+3HV yields (15.4 ± 2.36%wt.wt.) than under non-O₂ limited conditions (12.4 ± 2.26%wt.wt.). Notably, 50% RHCF was the most suitable medium for growth and PHB+PHV production, while 100% RHCF was the least suitable. The 3HV+3PV concentration (0.35 g/L), 3HV fraction (24%), and yield (15.4%wt.wt.) in 50% RHCF were highest under static, O₂-limited conditions, corresponding with negligible sugar utilization (1.6 mg/day.100 mL⁻¹ glucose) and suggesting alternative metabolic pathways using other substrates in the RHCF for growth. Nuclear magnetic resonance results indicated that Gordonia lacunae BS2^T produces a desirable co-polymer (PHBV), paving the way for ongoing research using this bacterium. Full article

(This article belongs to the Special Issue Novel and Old Insights for Biotechnological Exploitation of Actinomycetota Strain Fermentations)

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24 pages, 2524 KB

Open AccessArticle

Saccharomyces boulardii CNCM I-745 as a Probiotic Adjunct in Kefir: A Proof-of-Concept Study Comparing Traditional Grain and Industrial Starter Cultures

by Büşra Çınar, Deniz Koçan and Fatma Şahmurat

Fermentation 2026, 12(5), 249; https://doi.org/10.3390/fermentation12050249 - 20 May 2026

Abstract

Probiotic yeasts are increasingly proposed as adjuncts in fermented dairy products, but their behavior in kefir is still poorly described. This proof-of-concept study examined the effect of Saccharomyces boulardii CNCM I-745 supplementation on kefir produced with two traditional grain cultures and two industrial [...] Read more.

Probiotic yeasts are increasingly proposed as adjuncts in fermented dairy products, but their behavior in kefir is still poorly described. This proof-of-concept study examined the effect of Saccharomyces boulardii CNCM I-745 supplementation on kefir produced with two traditional grain cultures and two industrial direct-vat-inoculation cultures during 21 days of cold storage at 4 °C. Microbiological, physicochemical, and sensory parameters were monitored on days 1, 7, 14, and 21. The starter culture type was the main source of variation, with traditional grain kefirs showing higher microbial counts and better sensory scores than industrial cultures. S. boulardii did not change pH, titratable acidity, Lactococcus spp., or total mesophilic aerobic bacteria, indicating that it can be added without disturbing the established kefir microbiota or its acidification pattern. The probiotic yeast increased the total yeast count, slightly modulated Lactobacillus spp., and gave a small improvement in taste–aroma scores. In the yeast-free industrial culture, S. boulardii maintained viable counts above 6 log CFU/g throughout storage, showing that it can act as the sole yeast source in kefir matrices that lack indigenous yeast. Traditional grain kefirs kept a more stable overall sensory quality across 21 days than industrial cultures. The multivariate analysis confirmed two largely independent quality dimensions, one related to lactic acid bacteria and acidity and another to sensory perception. The study supports the use of S. boulardii as a probiotic adjunct in kefir and provides preliminary effect-size information for future, adequately replicated trials. Full article

(This article belongs to the Section Probiotic Strains and Fermentation)

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13 pages, 247 KB

Open AccessArticle

A Blend of Essential Oils (Blend of Eugenol, Linalool, Anethole, and Cinnamaldehyde) Increases Ruminal Propionate and Improves Total Tract Starch Digestibility in Steers Fed a Dry-Rolled Corn-Based Finishing Diet

by Federico Podversich, Jorge Bonilla Urbina, Callie Coble, Zachary K. F. Smith, Warren C. Rusche, Rebecca O’Sullivan, Mark J. Leggett, Sophie L. Parker-Norman and Ana Clara B. Menezes

Fermentation 2026, 12(5), 248; https://doi.org/10.3390/fermentation12050248 - 20 May 2026

Abstract

Feed additives based on essential oils (EOs) have emerged as a potential alternative to ionophores for diets with elevated grain inclusion. Also, on some occasions, EOs have been used in combination with monensin, with variable results. A metabolism trial was conducted using a [...] Read more.

Feed additives based on essential oils (EOs) have emerged as a potential alternative to ionophores for diets with elevated grain inclusion. Also, on some occasions, EOs have been used in combination with monensin, with variable results. A metabolism trial was conducted using a 2 × 2 factorial arrangement of treatments, evaluating supplementation with (A) monensin sodium (0 mg/steer daily vs. 400 mg. steer daily) and (B) a blend of EOs (eugenol, linalool, anethole, and cinnamaldehyde, 0 g/d vs. 14 g/d). Four Red Angus steers (BW = 435 ± 9.0 kg) with ruminal and duodenal cannulas were used, and the study was conducted as a Latin square with four periods of 28 days each. Ruminal fermentation and nutrient digestibility at different levels (ruminal, intestinal, and total tract) were determined. The EOs increased total tract starch digestibility (p = 0.05) by 4.5% and propionate concentration (p = 0.03) by 30.9%. Furthermore, EOs decreased acetate (p = 0.04) by 7.4% as well as the acetate to propionate ratio (p = 0.03). In conclusion, our results suggest that it is safe to combine this EO blend with monensin for feedlot diets. The EO blend improved starch digestibility and increased efficiency of the ruminal fermentation end-products, which suggests it could be beneficial in diets based upon grain. Full article

(This article belongs to the Special Issue Ruminal Fermentation: 2nd Edition)

22 pages, 12139 KB

Open AccessArticle

Ruminal Microbe Consortia for Biogas Production from Lignocellulosic Substrate

by Annabella Juhász-Erdélyi, Márta Huszár, Attila Farkas, Gergely Maróti, Roland Wirth, Márk Szuhaj, Zoltán Bagi, Kornél L. Kovács and Etelka Kovács

Fermentation 2026, 12(5), 247; https://doi.org/10.3390/fermentation12050247 - 19 May 2026

Abstract

Lignocellulose is degraded in the rumen by diverse microorganisms. This study aimed to select the top ruminal microbes associated with an anaerobic fungus (AF) capable of forming consortia that facilitate biogas production from wheat straw. The workflow included the following steps: (1) batch [...] Read more.

Lignocellulose is degraded in the rumen by diverse microorganisms. This study aimed to select the top ruminal microbes associated with an anaerobic fungus (AF) capable of forming consortia that facilitate biogas production from wheat straw. The workflow included the following steps: (1) batch reactors, divided into three compartments with porous membrane bags containing wheat straw, were assembled. The outermost compartment was inoculated with freshly collected rumen content. The first microbes colonizing the wheat straw in the innermost compartment within 72 h were identified. (2) Synthetic consortia were assembled comprising the following identified microbes: an anaerobic fungus (AF) (Neocallimastix lanati); methanogenic archaea (M) (Methanobrevibacter ruminantium or Methanobrevibacter gottschalkii); bacteria (B) (Butyrivibrio hungatei or Succinoclasticum ruminis). (3) Wheat straw was subjected to 7-day pretreatments with these synthetic consortia. (4) The pretreated straw served as substrate in biochemical methane potential (BMP) tests that used a biogas reactor digestate as the inoculum. The pretreated straw produced elevated biomethane yields; nonetheless, this process needs further optimization. The cross-kingdom AF + M + B consortia increased methane production by 35–70%, and superior volatile fatty acid production was confirmed via HPLC. The results suggest novel strategies for advanced practical biogas/biomethane technologies. Full article

(This article belongs to the Section Industrial Fermentation)

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22 pages, 17577 KB

Open AccessArticle

Valorization of Grape Seed By-Products by Lactiplantibacillus plantarum FBL002 Fermentation: Multi-Omics Insights into β-Glucosidase-Mediated Polyphenol Biotransformation and Antioxidant Enhancement

by Yuan Shi, Jianhua Cheng, Litao Hu, Jialiang Lin, Yan Wang, Hao Huang, Zihao Yu, Chunlu He, Wenjie Xu, Wuxia Chen, Yichen Fan, Weikang Cui, Yuan Ban, Shaonian Chang, Haiyang Ye and Haifeng Huang

Fermentation 2026, 12(5), 246; https://doi.org/10.3390/fermentation12050246 - 19 May 2026

Abstract

Grape seeds are a major by-product of grape processing and a rich source of polyphenolic compounds, yet their value remains underutilized. In this study, 12 lactic acid bacteria (LAB) strains were evaluated in a grape seed-based fermentation system to compare their tolerance, metabolic [...] Read more.

Grape seeds are a major by-product of grape processing and a rich source of polyphenolic compounds, yet their value remains underutilized. In this study, 12 lactic acid bacteria (LAB) strains were evaluated in a grape seed-based fermentation system to compare their tolerance, metabolic performance, and ability to promote polyphenol release. Among them, Lactiplantibacillus plantarum FBL002 showed the best overall performance. The strain maintained strong viability and metabolic activity at 5% grape seed concentration and released polyphenols more effectively than the other tested strains. The resulting fermentation broth also showed pronounced intracellular antioxidant activity. To clarify the basis of this phenotype, we further combined metabolomic, genomic, and transcriptomic analyses. Fermentation caused substantial shifts in phenolic metabolites, characterized by a decrease in glycosylated forms and an increase in more bioactive aglycones. Genome annotation revealed an enrichment of β-glucosidase-related genes in FBL002, and transcriptomic analysis showed that these genes were markedly upregulated during fermentation. This pattern was closely associated with the enhanced release of polyphenols. Together, these findings identify β-glucosidase as a key driver of grape seed polyphenol biotransformation by FBL002 and support the sustainable, high-value use of grape seeds in functional foods and cosmetic applications. Full article

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

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19 pages, 8120 KB

Open AccessReview

Lactic Acid Bacteria Exopolysaccharides as Next-Generation Clean-Label Texturizers and Prebiotics in Dairy Systems

by Yang Qiu, Tongyi Wang, Qiao Yang, Xiaoxue Liu, Chen Song and Renpeng Du

Fermentation 2026, 12(5), 245; https://doi.org/10.3390/fermentation12050245 - 19 May 2026

Abstract

Exopolysaccharides (EPSs) produced by lactic acid bacteria (LAB) are natural high-molecular-weight polymers secreted extracellularly during growth. They possess unique rheological properties and emulsifying stability and may exhibit prebiotic-related functionalities. In food systems, EPSs exhibit multiple functional values. In recent years, driven by the [...] Read more.

Exopolysaccharides (EPSs) produced by lactic acid bacteria (LAB) are natural high-molecular-weight polymers secreted extracellularly during growth. They possess unique rheological properties and emulsifying stability and may exhibit prebiotic-related functionalities. In food systems, EPSs exhibit multiple functional values. In recent years, driven by the global “Clean Label” movement and increasing consumer demand for natural and healthy foods, EPSs, as safe and traceable natural food-grade prebiotics, have attracted extensive attention in the dairy industry. This review summarizes EPSs’ structure, properties, and mechanisms in dairy systems. It focuses on their functional effects and mechanisms in typical dairy products such as yogurt, cheese, and ice cream, and analyzes the technical bottlenecks limiting large-scale production, including low yield, high cost, and challenges in separation and purification. This review further outlines several promising research directions for EPS research. These include strain modification via synthetic biology strategies, fermentation optimization using high-throughput screening technologies, and targeted application based on structure–function relationships. It aims to provide systematic theoretical references and practical guidance for the efficient development and innovative application of EPSs in the food industry. Full article

(This article belongs to the Special Issue The Roles of Lactic Acid Bacteria in Food Fermentation)

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