Search Results (213)

This study investigated the synergistic effects of liquid fermentation of rapeseed meal (RSM) on feed microbiota, growth performance, and muscle development in growing pigs. RSM was fermented using four compound probiotics and eleven enzyme preparations, and microbial changes were analyzed using 16S rRNA sequencing. Seventy-two Duroc × Jingfen White pigs were randomly assigned to three groups: soybean meal (Ctrl), RSM, and fermented RSM (FRSM). FRSM showed higher trichloroacetic acid-soluble protein (TCA-sp) content and significantly lower neutral detergent fiber (NDF), acid detergent fiber (ADF), anti-nutritional factors (ANFs), and toxins (TS) (p < 0.01). Fermentation increased microbial diversity, with higher abundances of Lactobacillus and Pediococcus. Compared with Ctrl and RSM, the feed-to-gain ratio (F/G) decreased in the FRSM group (p < 0.01). FRSM also improved serum antioxidant capacity, enhanced intestinal villus height (VH)and villus height/crypt depth ratio (VH/CD), and upregulated the expression of tight junction proteins (ZO-1, occludin) and the anti-inflammatory factor IL-10 (p < 0.01). FRSM group also increased myofiber diameter and cross-sectional area in the longissimus dorsi and elevated MyoD, MyoG and Myf5 expression (p < 0.01). RNA-seq revealed 2094 differentially expressed genes enriched in metabolic pathways. Overall, FRSM improved growth performance, intestinal health, and muscle development in growing pigs, which may guide the development of protein resource utilization technologies. Full article

The rumen simulation technique (RUSITEC^®) is a known model for research in rumen microbiology and fermentation. However, our research group observed inconsistencies in gas production across trials. This study investigated the effects of different gas outlet locations on digestibility, ruminal fermentation, gas production, and microbial protein synthesis. Fifteen fermenters tested three different gas outlet locations within the RUSITEC^® equipment: (1) gas outlet directly on the effluent vessel for output liquid (EV); (2) gas outlet directly on fermenter cap (F); and (3) gas outlet on both effluent vessel and fermenter cap (EVF). Data were analyzed using a completely randomized design in SAS (v. 9.4) with the MIXED procedure, and significance was set at p < 0.10. Results showed that altering the gas outlet location did not affect nutrient digestibility (p > 0.10), microbial protein synthesis (p > 0.10), and volatile fatty acid (VFA) production when expressed on a molar basis (p > 0.10). However, total gas production (p = 0.108) was higher in the EVF group and ammonia nitrogen produced in the fermenter was higher in group F (p = 0.081). Furthermore, methane (CH₄) production was underestimated when the gas outlet location was in just one of the locations when compared to the EVF group (p = 0.006). VFA proportion was also affected, with lower acetate (p = 0.005) and higher butyrate (p = 0.014) for group EV. These results indicate that the location of the gas outlet is an important methodological factor affecting fermentation measurements in the RUSITEC system, with outlets positioned in both the effluent and fermenter vessels enhancing gas recovery. Full article

Kombucha fermentation is driven by a Symbiotic Culture of Bacteria and Yeast (SCOBY), a cellulose-rich biofilm that hosts a complex microbial consortium. While most kombucha studies focus on the liquid beverage, the SCOBY pellicle itself remains underexplored, particularly with respect to species-level microbial resolution and its intrinsic biological activities. In this study, a commercial kombucha SCOBY was characterized using full-length 16S rRNA gene and ITS amplicon sequencing based on Oxford Nanopore Technology, enabling species-level taxonomic resolution. In parallel, hydroalcoholic and aqueous extracts of dried SCOBY biomass were evaluated for in vitro antioxidant activity (DPPH and ABTS assays), antidiabetic-related enzyme inhibition (α-glucosidase and dipeptidyl peptidase-4, DPP4), and anti-aging-related enzyme inhibition (tyrosinase and elastase). The SCOBY bacterial community was strongly dominated by acetic acid bacteria, with Komagataeibacter saccharivorans and Acetobacter tropicalis accounting for more than 60% of total reads, reflecting a biofilm structure optimized for cellulose production and oxidative metabolism. The yeast community showed marked unevenness, with Brettanomyces bruxellensis representing over 80% of reads, consistent with its known role in ethanol production and stress tolerance within kombucha systems. In vitro assays revealed that hydroalcoholic SCOBY extracts consistently exhibited higher biological activity than aqueous extracts across all tested assays. However, both extracts showed substantially lower potency than purified reference compounds, indicating moderate but measurable bioactivity typical of complex fermented matrices. These findings support the potential valorization of SCOBY as a fermentation-derived biomaterial and functional ingredient while underscoring the need for further chemical characterization, mechanistic studies, and biological validation beyond enzyme-based assays. Full article

Catalpol, one of the primary bioactive components in Rehmannia glutinosa, is an iridoid glycoside with significant pharmacological activities. To expand the microbial sources of catalpol, endophytic bacteria were isolated from R. glutinosa (cultivated in Jiaozuo, China) using the dilution plating method combined with vanillin–sulfuric acid colorimetric assay. High-performance liquid chromatography (HPLC) and liquid chromatography–mass spectrometry (LC-MS) were employed for screening and identification. The isolated strain was identified through morphological characterization and 16S rDNA gene sequence analysis, while single-factor experiments coupled with response surface methodology were utilized to optimize its fermentation conditions. Results indicated that the strain DH14 formed circular, cream-white, opaque colonies and was Gram-negative. It was identified as Brevundimonas olei. The optimal fermentation conditions were determined to be 190 rpm, pH 7.6, 31 °C, and 0% NaCl. Meanwhile, the results revealed a positive correlation between the pH of the fermentation broth and catalpol production. Under the optimized conditions, the maximum catalpol yield reached 0.142 mg/mL after 3 days of cultivation. This study provides a promising microbial resource and optimized fermentation parameters for the microbial production of catalpol. Full article

The endangered ethnomedicinal plant Euchresta tubulosa harbors a valuable community of endophytic fungi, demonstrating significant potential for biotechnological applications. Endophytic fungi were isolated from E. tubulosa and identified to characterize their secondary metabolites and extracellular enzyme activities. Endophytic fungi were isolated from E. tubulosa using tissue explant culture and identified by morphological and molecular (ITS) analysis. The chemical profiles of strain fermentation products were analyzed by LC–MS/MS, while extracellular enzyme production (cellulase, protease, amylase) was assessed through chromogenic plate assays and liquid fermentation. The results indicated that a total of 55 endophytic fungi were isolated from E. tubulosa, assigned to 17 genera. Among these, three genera (Colletotrichum, Fusarium, and Penicillium) constituted the dominant groups, while four strains (including three novel species) represented potential new taxa. LC–MS/MS analysis revealed that fermentation products of the three novel endophytic fungal species contained bioactive compounds such as flavonoids and alkaloids; furthermore, bioactivity assays indicate that they exhibited significant degrees of antibacterial and antioxidant activity. Extracellular enzyme assays demonstrated that three E. tubulosa-derived endophytic strains exhibited multi-hydrolytic enzyme production capabilities. Notably, strain ETG-1-2-1 showed the highest amylase and cellulase activities (10.95 U/mL and 9.68 U/mL, respectively), while strain ETXG-1-1-1 displayed the highest protease activity (2.34 U/mL). This study provides the first systematic report on the diversity of endophytic fungi in E. tubulosa, their secondary metabolite profiles, and extracellular enzyme activities, establishing a theoretical foundation for discovering novel bioactive compounds and developing microbial resources, while also highlighting their ecological roles and biotechnological potential. Full article

In this work, we present the scale-up of a batch anaerobic fermentation system for the production of succinic acid from glycerol using A. succinogenes. The system has been successfully scaled up from an initial bioreactor working volume of 1 L (laboratory scale) to a working volume of 100 L (pilot scale). At the same time, we have developed a hybrid model, combining the intrinsic kinetics of the microbial growth, with a computational fluid dynamics model (CFD) of the bioreactor. The proposed model is able to predict the productivity drop, usually observed while scaling up a bioprocess. In our process, this is a result of the limitations on the mass transfer of CO₂ between the gas and the liquid phase of the system. The model is successfully used to predict the amount of aeration needed in order to achieve increased succinic acid productivity. Using the model, the final succinic acid increased by 4.3%, and the succinic acid productivity increased by 8.5%, while the fermentation by-products decreased by approxiamtely 3% each. Full article

Freeze–thaw cycles on the Qinghai–Tibetan Plateau inhibit microbial activity and challenge silage preservation. This paper aimed to elucidate how an indigenous, freeze–thaw-resistant Lactobacillus plantarum strain (LP160) improves oat silage quality under such stress. Oats were ensiled for 60 days under constant 20 °C (t) or freeze–thaw cycles (12 h at 20 °C/−5 °C; s) with or without LP160 inoculation. Samples after ensiling and 5-day aerobic exposure were analyzed for fermentation parameters, nutrients, microbiome, and non-targeted metabolomics using liquid chromatography–tandem mass spectrometry (LC-MS/MS). LP160 inoculation improved silage quality, as shown by the lower pH, ammoniacal nitrogen, neutral detergent fiber, acid detergent fiber contents as well as the greater amount of lactic acid. Key findings demonstrated that LP160 inoculation significantly enhanced Lactobacillus dominance, effectively curbed the growth of detrimental bacteria like Mucor, and regulated the microbial structure. During the aerobic exposure phase, the microbial community structures and successions varied under different temperature treatments. When inoculated under freeze–thaw conditions, the genus Bacillus increased, while Paenibacillus was not impeded. A total of 943 metabolites were identified, predominantly comprising amino acids, fatty acids, and the like. The expressions of metabolites with antioxidant and antibacterial properties were upregulated with LP160 inoculation. This led to the inhibition of protein hydrolysis and a reduction in ammonia–nitrogen production. The results of correlation analysis indicated that inoculating LP160 suppressed the proliferation of Mucor and enhanced the abundance of Torulaspora; meanwhile, the expression of L-palmitoylcarnitine involved in the fatty acid degradation pathway and fatty acid metabolism pathway was inhibited along with the generation of ammonia–nitrogen. Consequently, the degradation of fatty acids and proteins was restrained. The results of this paper provided new insights into the silage under freeze–thaw conditions. Full article

Biopolymers from renewable sources are increasingly explored to reduce the carbon footprint of materials and mitigate plastic pollution. This review synthesizes the last five years of progress across the biopolymer value chain, comparing plant, microbial/fermentation, fungal, and marine/algal resources and critically assessing greener extraction and fractionation routes (ultrasound and microwave intensification, subcritical water, supercritical CO₂ with co-solvents, ionic liquids, deep eutectic solvents including natural deep eutectic solvents, and enzymatic or bio-mediated processes). We emphasize yield-selectivity trade-offs, scalability, energy demand, and solvent recovery. Downstream, we summarize purification and performance tuning via crosslinking, derivatization, blending/plasticization, and nanocomposites, and we map advanced characterization to targeted functional properties to bridge processing choices with end-use performance. Applications are organized across food and agriculture, biomedical and pharmaceutical technologies, packaging, and cosmetics, with cross-cutting attention to safety and regulatory compliance, quality-by-design, techno-economics, and life-cycle assessment. Key bottlenecks are feedstock variability, viscosity and recyclability limitations of designer solvents, and persistent gaps in barrier and thermal properties versus petrochemical benchmarks, compounded by uneven composting and recycling infrastructure. Promising directions include low-viscosity or switchable solvents, data- and artificial intelligence (AI)-guided process optimization, engineered biopolymers, and circular end-of-life strategies that align material design with realistic recovery routes. Full article

Indigo dyeing is a traditional microbial fermentation process practiced worldwide using plants that produce indican, a precursor of indigo. In Okinawa Prefecture, Japan, indigo dyeing is traditionally performed using a muddy suspension containing indigo, prepared from Strobilanthes cusia. In this region, the addition of a fully fermented dye liquid, Tomodane, is believed to promote fermentation, although its microbial basis remains unclear. In this study, we developed a laboratory-scale indigo fermentation system with biological replication to investigate the effects of Tomodane supplementation on the dyeing intensity, bacterial community dynamics, and indigo particle size. Fermentation supplemented with Tomodane showed an earlier onset of fabric dyeing than fermentation without Tomodane. Microbial community analyses revealed that the bacterial communities in Tomodane-supplemented fermentation converged more rapidly toward a stable community structure. Additionally, bacterial taxa putatively associated with extracellular electron transfer (EET), a process relevant to indigo reduction, were more abundant in the bacterial community at earlier fermentation stages in the presence of Tomodane. Indigo particle size decreased more rapidly during Tomodane-supplemented fermentation, coinciding with an earlier dyeing onset. These results suggest that Tomodane facilitates indigo fermentation by facilitating the early establishment of a functionally competent microbial community capable of efficient indigo reduction. Full article

Spent coffee grounds are an abundant agro-industrial by-product with considerable potential as a functional food ingredient. This study investigated the effects of lactic acid fermentation on the antioxidant and anti-inflammatory activities of spent coffee grounds, as evaluated using their extracts, with a focus on fermentation-induced remodeling of phenolic compounds and the functional implications. Fermentation was conducted using Lactobacillus plantarum, and changes in microbial growth, pH, reducing sugar content, phenolic composition, antioxidant capacity, and anti-inflammatory activity were evaluated. During fermentation, viable cell counts increased from 6.73 log colony-forming units (CFU)/mL at 0 h to 9.27 log CFU/mL at 48 h, accompanied by a decrease in pH and an increase in reducing sugar content, indicating active microbial metabolism. Total polyphenol content increased markedly, reaching 97.44 mg gallic acid equivalents (GAE)/100 g in water extracts fermented for 48 h compared with 62.96 mg GAE/100 g in non-fermented controls. High-performance liquid chromatography analysis revealed significant enrichment of phenolic acids, including caffeic, ferulic, and protocatechuic acids. Correspondingly, fermented extracts exhibited enhanced antioxidant activities, as determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), superoxide dismutase (SOD-like, and catalase assays. In addition, fermented extracts showed improved cellular compatibility and significantly inhibited nitric oxide production (approximately 50–60% at 200–300 μg/mL) and pro-inflammatory cytokine production, with interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) inhibition rates exceeding 60% at 200–300 μg/mL in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. These biological effects were closely linked to fermentation-induced qualitative and quantitative changes in phenolic composition, providing mechanistic insight beyond simple activity enhancement. Overall, lactic acid fermentation enhances the functional properties of spent coffee grounds, highlighting their potential as upcycled, value-added ingredients for functional food and nutraceutical applications. Full article

The rapid expansion of anaerobic digestion (AD) as a key technology for producing renewable energy has led to a substantial increase in digestate generation. This has intensified the need for sustainable management strategies that align with circular economy principles. While the solid fraction of digestate (SD) is traditionally applied to land or composted, its heterogeneous composition, regulatory constraints, and handling challenges restrict its wider use. This review aims to clarify the current state of SD treatment and highlight emerging opportunities to convert this underexploited resource into value-added bioproducts. A systematic bibliographic analysis of the past decade was conducted to identify consolidated and emerging SD valorisation technologies, supported by an evaluation of EU-level regulatory frameworks and the role of mechanical solid–liquid separation in enabling downstream valorisation. In addition, a comprehensive comparative table compiling physicochemical characterisation data of SD from various feedstocks and separation methods is presented, emphasising the significant variability in composition and its implications for valorisation pathways. The results show that, while composting and thermochemical routes, particularly pyrolysis, remain predominant, novel approaches such as advanced drying, pelletisation, vermicomposting, insect bioconversion, and fermentation-based pathways (including submerged and solid-state fermentation) are rapidly gaining interest. These emerging technologies enable the production of high-value products such as biochar, pellets, enzymes, microbial biopesticides, protein sources, and fungal biomass. However, their adoption is currently limited by feedstock heterogeneity, process complexity, scalability constraints, and economic considerations. Overall, SD is a versatile feedstock whose valorisation is expanding beyond agricultural applications. However, regulatory harmonisation, quality assurance, and process optimisation are still needed to encourage industrial uptake and to fully integrate SD into circular bioeconomy frameworks. Full article

Cassava is a major starch crop in Africa, generating substantial amounts of solid (peels and fibres) and liquid (process press water) residues that remain underutilised, particularly in smallholder and semi-industrial processing units. In Mozambique, where cassava is a staple and processed primarily by local farmer associations, these residues—readily available and low-cost feedstocks—have significant potential for value-added applications. This study evaluated the potential of enzymatically hydrolysed cassava residues—peel and fibre hydrolysates—as substrates for independent yeast fermentations targeting microbial lipid and ethanol production. Rhodotorula toruloides CBS 14 efficiently converted sugars from both hydrolysates, producing up to 17.14 g L⁻¹ of cell dry weight (CDW) and 35% intracellular lipid content from the peel hydrolysate, and 16.5 g L⁻¹ CDW with 50% lipids from the fibre hydrolysate. Supplementation with ammonium sulphate accelerated sugar utilisation and reduced fermentation time but did not significantly increase the biomass or lipid yields. Saccharomyces cerevisiae J672 fermented the available sugars anaerobically, achieving ethanol yields of 0.45 ± 0.03 g g⁻¹ glucose from peels and 0.37 ± 0.06 g g⁻¹ glucose from fibres. These findings highlight the regional relevance of valorising cassava processing residues in Mozambique and demonstrate a dual-product valorisation strategy, whereby the same feedstocks are converted into either microbial lipids or ethanol through independent fermentations. This approach supports the sustainable, low-cost utilisation of agro-industrial residues, contributing to circular bioeconomy principles and enhancing the environmental and economic value of local cassava value chains. Full article

This study first adopted a liquid microbial-enzymatic co-fermentation process to enhance the nutritional value of walnut meal (WM) and sesame meal (SM), and systematically evaluated its effect on the nutrient digestibility of growing pigs. WM and SM are two underutilized high-protein by-products, whose application is hindered by anti-nutritional tannin and fiber. Optimal fermentation parameters were determined via single-factor experiments and response surface methodology, utilizing a consortium of Lactobacillus I, Candida utilis, and protease. Fermentation significantly reduced tannin (39.41% in WM) and crude fibre (28.79% in WM), reduced tannin (18.67% in SM) and crude fibre (4.00% in SM), while elevating crude protein (10.63% in WM, 7.47% in SM) and acid-soluble protein in both WM and SM. Results of the microstructure of fermented WM and SM revealed structural loosening, surface porosity, and polysaccharide degradation. Microbial community shifts highlighted the dominance of Lactobacillus and Bacillus in fermented substrates. In growing pigs, fermented WM and SM exhibited improved standardized ileal digestibility (SID) of key amino acids (threonine, tryptophan, valine; p < 0.05), alongside enhanced digestible energy (DE) and metabolizable energy (ME) for SM (p < 0.05). These findings demonstrate that liquid co-fermentation effectively degrades anti-nutritional factors, enhances nutrient bio-availability, and positions WM and SM as viable alternatives to conventional protein sources in swine diets, supporting strategies to reduce reliance on soybean meal. Full article

Microbial lipid production from renewable carbon sources, particularly lignocellulosic hydrolysates, is a promising alternative to plant-derived oils and fats for food applications, as it can minimize the land use by utilizing agricultural wastes and byproducts from food production. In this context, a standard approach to prevent oxygen limitation at reduced air gassing rates during long-term aerobic microbial processes is to operate bioreactors at increased pressure for elevating the gas solubility in the fermentation broth. This study investigates the effect of absolute pressures of up to 2.5 bar on the conversion of the carbon sources (glucose, xylose, and acetate), growth, and lipid biosynthesis by Cutaneotrichosporon oleaginosus converting a synthetic nutrient-rich lignocellulosic hydrolysate at low air gassing rates of 0.1 vessel volume per minute (vvm). Increasing pressure delayed xylose uptake, reduced acetic acid consumption, and reduced biomass formation. Lipid accumulation decreased with increasing pressure, except for fermentations at 1.5 bar, which achieved a maximum lipid content of 83.6% (±1.6, w/w) (weight per weight in %). At an absolute pressure of 1.5 bar, a lipid yield from glucose, xylose, and acetic acid of 38% (w/w) was reached after 6 days of fermentation. The pressure sensitivity of C. oleaginosus may pose challenges on an industrial scale due to the dynamic changes in pressure when the yeast cells pass through the bioreactor. Increasing liquid heights in full-scale bioreactors will result in increased hydrostatic pressures at the bottom, substantially reducing lipid yields, e.g., to only 23% (w/w) at 2.0–2.5 bar, as shown in this study. However, further scale-up studies with dynamic pressure regimes (1–2.5 bar) may help to evaluate scale-up feasibility. Full article

China annually produces around 20 million tons of distiller’s grains, whose utilization is important for resource efficiency. These grains are rich in crude protein (CP), crude fiber (CF), and other nutrients, though their composition varies by grain type. This study applied a microbial–enzyme synergistic liquid fermentation process to two types—strong-aroma and soy-sauce-aroma grains—using a composite inoculant (Lactobacillus, Saccharomyces cerevisiae, Bacillus, each >1 × 10⁹ CFU/g) along with xylanase, cellulase, and protease. Optimal fermentation conditions were identified: for strong-aroma grains—water-to-grain material ratio 1.8, inoculum 0.25%, 25 °C, 16 h; for soy-sauce-aroma grains—ratio 1.8, inoculum 0.3%, 25.5 °C, 13 h. After fermentation, CP increased by 13.62% and CF decreased by 30.37% in strong-aroma grains, while in soy-sauce-aroma grains an 8.83% CP increase and 31.31% CF reduction were observed. Structural analysis of both grains showed looser fibrous formations and changes in protein secondary structure. Full article