Search Results (1,786)

Background/Objectives: This study evaluated the effects of a compound probiotic fermented feed (CPFF) containing Lactobacillus plantarum, Bacillus subtilis, yeast, and Aspergillus niger on rumen in vitro fermentation, in situ feed degradation, and growth performance in beef cattle. Methods: We established a control group (CON) and experimental groups with 2%, 4%, and 8% CPFF supplementation for in vitro fermentation. Results: The results indicated that the NH₃-N concentration in the 4% CPFF group was significantly higher than in the other groups (p < 0.001). Similarly, microbial crude protein (MCP) production was significantly greater in the 4% CPFF group compared to the CON group (p = 0.016). The molar proportions of acetate, butyrate, isobutyrate, and valerate were significantly higher in the 2% and 4% CPFF groups than in the control group (p < 0.001), while propionate levels were significantly lower (p < 0.001). After 48 h, gas production was highest in the 4% CPFF group. Based on improvements in gas production, MCP synthesis, and fermentation intensity, the 4% inclusion level was determined to be optimal for further studies. We conducted an in situ degradation trial using 4% CPFF. Results showed that at 12 h, the neutral detergent fiber (NDF) degradation rate in the 4% CPFF group was significantly higher than in the CON group at 4, 8, 12, and 48 h (p < 0.05). At 48 h, the acid detergent fiber (ADF) degradation rate in the 4% CPFF group was also significantly higher than in the CON group (p < 0.001), and this group exhibited a significant increase in crude protein (CP) degradation (p = 0.030). We analyzed rumen fluid samples from both the CON and 4% CPFF groups after in vitro fermentation using 16S rRNA sequencing and untargeted metabolomics. Microbial community analysis revealed significantly increased abundances of functional bacterial groups such as Rikenellaceae_RC9_gut_group, Christensenellaceae_R-7_group, and UCG-002 in the 4% CPFF group (p < 0.05). Differential metabolites were primarily involved in pathways related to tryptophan metabolism, and tyrosine metabolism signaling. A feeding trial was conducted by adding 4% CPFF to the diet of Angus growing cattle. The results indicated that average daily gain (ADG) (p = 0.004) and average daily feed intake (ADFI) (p = 0.001) were significantly higher in the CPFF group than in the CON group. Conclusions: In conclusion, our results demonstrate that CPFF enhances rumen fermentation activity, optimizes the microbiota and metabolic profiles of rumen fluid, and improves the average daily gain of beef cattle. This research provides a valuable theoretical basis for applying CPFF in beef cattle breeding. Full article

Host-adapted probiotics offer a promising strategy for improving stingless bee nutrition and colony sustainability. In this study, gut-derived lactic acid bacteria (LAB) isolated from Heterotrigona itama were evaluated for probiotic potential and used to develop fermented bee pollen. Of 37 presumptive LAB isolates, three strains (BP-2, BP-3, and BPW-B1) exhibited strong tolerance to simulated gastrointestinal conditions, favorable adhesion-related properties, and acceptable safety profiles. Phylogenetic and biochemical analyses identified the selected isolates as Apilactobacillus kunkeei. The LAB strains were co-cultured with the osmophilic yeasts Zygosaccharomyces bailii TSU_YK2 and Starmerella meliponinorum TSU_YP10 to establish a host-associated LAB–yeast co-fermentation model that mimics stingless bee pollen fermentation. Co-fermentation significantly improved protein digestibility, organic acid production, antioxidant activity, and microbial viability relative to spontaneous fermentation controls (p < 0.05). Feeding experiments demonstrated that probiotic-fermented pollen increased feed intake, body weight, abdominal lipid reserves, hypopharyngeal gland development, and survival among H. itama workers. In addition, probiotic supplementation was associated with shifts in the dominant gut-associated bacterial taxa, including Lactobacillus, Bifidobacterium, and Snodgrassella. This study demonstrates the potential of combining gut-derived A. kunkeei with osmophilic yeasts as a functional fermentation starter culture to develop biologically relevant probiotic feed supplements for stingless bees. Full article

This study examined the physicochemical, microbiological, textural, organic acid, colour, and sensory aspects of cabbage pickles made with fermented dairy by-products as a brine medium. Yoghurt whey, whey, kefir whey, and buttermilk were used as brine media and compared with vinegar. Brine samples showed substantial changes in pH, Brix, colour, and rheology (p < 0.05). Yoghurt whey-based samples had the lowest brine pH (2.87) and Brix (10.04%), while buttermilk samples had the highest pH (3.26) and Brix (10.83%). Vinegar-based brine showed higher a* and b* values, whereas yoghurt whey-based brine had the highest L*. Yoghurt whey-based samples had lower consistency and a lower viscosity index. Pickle samples made with different brine types showed significant differences in physicochemical, microbiological, textural, and organic acid properties (p < 0.05). Pickle samples made with vinegar had the lowest pH (2.99), while samples made with buttermilk had the highest (3.31). Vinegar-based pickles had the highest dry matter (5.27%) and drained weight (64.15%). Yoghurt whey-based samples had the highest counts of Lactobacillus spp. (6.38 log CFU/g) and Lactococcus/Streptococcus (6.81 log CFU/g), while vinegar-based samples had the highest counts of acetic acid bacteria and total aerobic mesophilic bacteria. However, kefir whey-based samples had the highest yeast count (5.72 log CFU/g). The textural analysis showed that yoghurt whey-based samples had the highest hardness (471.72 N) and springiness, whereas buttermilk-based samples had higher adhesiveness and cohesiveness. Whey-based samples had the highest gumminess and chewiness. Yoghurt whey-based samples had the highest levels of lactic acid (14,569.39 mg/L) and citric acid, whereas vinegar-based samples had the highest levels of acetic acid (63,795.64 mg/L) and propionic acid. Kefir whey-based samples had the highest butyric acid content. Yoghurt whey-based pickles were the most popular with panellists, followed by whey and vinegar-based pickles. Buttermilk-based samples scored lowest in sensory rating. Finally, fermented dairy by-products can be used as a functional brine medium for cabbage pickle. Yoghurt whey has shown promise in improving microbiological quality, textural characteristics, and sensory acceptability. Using dairy industry by-products in pickle making is an innovative way to produce sustainable food and add value to by-products. Full article

Coffee cherry pulp (CCP; cascara), a major by-product of coffee processing, has gained increasing attention as a sustainable source of phenolic compounds, dietary fiber, and other bioactive constituents with applications in food, nutraceutical, feed, and biomaterial industries. However, its utilization remains limited by compositional variability, anti-nutritional compounds, and inefficiencies in conventional processing. Controlled fermentation has emerged as a promising strategy to enhance the release, transformation, and bioavailability of CCP-derived bioactive through targeted microbial biotransformation and controlled bioprocessing. This review summarizes recent advances in enzymatic pretreatment, microbial fermentation, and metabolite-directed processing, with emphasis on their effects on phenolic transformation, antioxidant activity, and functional properties. The roles of selected lactic acid bacteria, yeasts, and microbial consortia in improving the nutritional, sensory, and biological characteristics of CCP-derived products are critically discussed. Potential applications of fermented CCP in functional foods and beverages, bioactive ingredients, biopolymers, and animal feed are also highlighted within the framework of an integrated circular bioeconomy. Finally, current challenges and future perspectives related to process scalability, metabolite control, regulatory approval, and AI-assisted bioprocess optimization are addressed. Full article

Saccharomyces cerevisiae yeast products are used to stabilize dairy cattle rumen environments. In this study, multiparous lactating Holstein–Jersey cross cows in late lactation (n = 12; ±150 DIM) were used in a replicated 4 × 4 Latin square design over four 21 d periods to evaluate yeast supplementation on dry matter intake (DMI), milk production, milk components, rumen pH, and redox potential (E_h). A subset of four ruminally cannulated cows were selected for rumen measurements. Treatments included no additive (CON), 14 g yeast culture additive (YCA), 5 g active dry yeast (ADY), and 5 g ADY + 5 g yeast extract additive (YEA) top-dressed once daily. Data were analyzed using GLIMMIX in SAS 9.4, with significance at p ≤ 0.05 and tendencies at p ≤ 0.15. Dry matter intake did not differ among treatments (p > 0.15) but decreased over time (p < 0.05). Milk production, efficiency, lactose, and total solids were not affected (p > 0.15). YCA tended to increase milk fat and fatty acid fractions compared with CON (p < 0.15). Protein in milk was greater in CON (p < 0.05; p < 0.05) than YCA and YEA. Active dry yeast treatments increased the frequency of a buffered rumen (p < 0.05) and promoted a more reducing ruminal environment, characterized by lower redox potential and conditions favorable for anaerobic fermentation (p < 0.05). Overall, supplementing active dry yeasts to dairy cows in late lactation did not affect DMI, production efficiency, or milk quality, but may maintain rumen pH stability. Full article

The use of Kluyveromyces marxianus in mixed cultures for fermentation processes has become increasingly relevant. This yeast is characterized by rapid growth, thermotolerance, broad sugar utilization, and the ability to produce aroma-active compounds. In this study, we evaluated changes in the growth and volatilome of a K. marxianus strain isolated from agave fermentation under microbial competition induced by co-cultivation interactions and nutritional limitation induced by a nutrient-deficient medium. The results indicate that these stress factors are significant drivers of metabolic changes, leading to substantial increases in the concentrations of key aromatic compounds. Stress-free conditions favor cell growth and the production of stable, reproducible volatile profiles, which is advantageous for batch-to-batch consistency (as in wine or mezcal production). While microbial competition and nutritional limitation induce reduced cell growth and loss of viability, they also lead to increased aromatic diversity, particularly the synthesis of β-phenethyl acetate, ethyl octanoate, and ethyl hexanoate. These findings demonstrate a relationship between environmental stress and the development of volatile profile complexity, offering new insights into harnessing stress-induced changes in the volatilome to optimize the sensory profile of traditional fermentations. Full article

In recent years, the wine industry has searched for alternatives to reduce the use of sulfites, with ultra-high-pressure homogenization (UHPH) emerging as a promising technology. The objective of this study was to evaluate the combined effect of UHPH and non-Saccharomyces yeasts (Lachancea thermotolerans and Metschnikowia pulcherrima) on wine quality. To this end, fermentations were carried out using control Verdejo must, must treated with UHPH, and must treated with 50 mg/L SO₂, using pure cultures and co-inoculations. Enological parameters, volatile compounds, colour, redox potential, and sensory profile were analyzed. The results showed that the co-inoculation of L. thermotolerans and M. pulcherrima reduced the final ethanol content by 0.5% (v/v) and increased lactic acid production, resulting in a decrease in pH of 0.3 units; however, L. thermotolerans in monoculture failed to implant properly in UHPH-treated must. In addition, wines from UHPH-treated musts exhibited 20% lower redox potential, suggesting that treatment with UHPH was effective in inactivating oxidative enzymes, as did those fermented with M. pulcherrima. Regarding volatile compounds, UHPH wines showed a 30% reduction in higher alcohols and carbonyl compounds, resulting in a characteristic aromatic profile that was positively evaluated in sensory analysis. In conclusion, the combination of UHPH and non-Saccharomyces yeasts represents an effective strategy for improving wine quality and reducing the use of sulfites. Full article

This research presents bacterial cellulose (BC) filaments knitted from agro-industrial by-products. The fermentation media came from pressed fruit (beetroot, ginger, grape), vegetable beverages, bagasse with different concentrations (1/2.5, 1/5, 1/7.5, and 1/10), and a control medium with unrefined sugar from sugarcane or panela. The BC filaments were obtained from a mixed culture of bacteria and yeast (SCOBY); functionalized using NaOH purification treatment and glycerol plasticizer; untwisted and twisted with 1-, 2-, and 4-ply; and characterized physically and mechanically by weight, diameter, tensile strength, Young’s modulus, and elongation. The untwisted and 2-ply twisted BC filaments from the fruit medium 1/2.5 showed tensile strength of 272 MPa and 155 MPa, respectively. Finally, control panela filaments with 1-, 2-, and 4-ply and fruit filaments with 2- and 4-ply were knitted in wet states. This research demonstrates the use of by-products to produce BC filaments with knitting properties for textile applications. Full article

Non-fried whole-wheat instant noodles feature high dietary fiber and balanced nutrition but suffer from poor rehydration, texture, and flavor. This study aims to improve the quality of these noodles through mixed fermentation of yeast and lactic acid bacteria (LAB). The rehydration characteristics, textural profile, sensory quality, microstructure, volatile flavor compounds, and in vitro digestibility of non-fried instant whole-wheat noodles were evaluated. Yeast primarily reduced rehydration time and improved mouthfeel, whereas LAB mainly contributed to the formation of a continuous and uniform gluten network as well as the enhancement of noodle flavor. Moderate addition of the mixed culture (1% yeast + 0.05% LAB) promoted the construction of a homogeneous gluten network in non-fried whole-wheat instant noodles, effectively reducing starch digestibility and estimated glycemic index (eGI). However, excessive addition caused opposite effects on these noodles. This study provides an effective processing strategy for the production of high-quality, low-eGI whole-wheat instant noodles, which are suitable for people pursuing healthy diets and controlling blood sugar levels. Full article

Pectinases are a group of enzymes widely applied in agri-food processes. This study aimed to isolate and characterize pectinase-producing yeasts and yeast-like fungi from soil and humus samples collected in a Moroccan argan forest, a region characterized by arid to semi-arid climatic conditions, with emphasis on screening and evaluating their pectinolytic activity. Among nine isolated strains, four exhibited detectable pectinolytic activity on pectin agar medium. Two promising isolates were molecularly identified by ITS region sequencing as Coniochaeta pulveracea PX765016 and Coniochaeta ligniaria PX765017. Notably, C. pulveracea PX765016 showed the highest pectinolytic potential, with a pectinolytic degradation index of 4.2 on pectin agar. This strain also exhibited maximal pectinase production after 96 h of submerged fermentation in YEPD medium under optimized conditions of pH 4, 30–35 °C, and 0.5% (w/v) pectin. The crude enzyme obtained under these conditions exhibited a specific activity of 559.90 ± 11.62 U/mg. The enzyme was subsequently subjected to sequential purification comprising ammonium sulfate precipitation, dialysis, and gel filtration chromatography on a Sephadex G-100 column, yielding a 2.99-fold purification with a final recovery of 14%. The purified enzyme exhibited optimal activity at pH 6.0 and 40–55 °C, with a reaction time of 20 min. Kinetic analysis of pectin hydrolysis revealed a Michaelis–Menten constant (Km) of 7.33 mg pectin per mL and a maximum reaction velocity (Vmax) of 1666.7 U/mg. To the best of our knowledge, this is the first report of pectinase production by a member of the genus Coniochaeta, and the first characterization of pectinase activity from C. pulveracea. Full article

Traditional cheese products harbor complex microbial communities that influence their quality and safety. However, the effects of processing scale and manufacturing stage on the microbial profile of hurood, a traditional Mongolian cheese, remain poorly understood. This study examined microbial indicators, community composition, and succession dynamics across four manufacturing stages (raw milk, yogurt, whey, and hurood) and three processing scales (pastoral household, workshop, and factory) using plate counting and 16S rRNA gene amplicon sequencing. Twenty-four samples were collected from Xilin Gol, Inner Mongolia. Total aerobic plate counts and coliform counts decreased significantly from raw milk (7.30 and 4.49 log CFU/g, respectively) to hurood (2.02 and 0.34 log CFU/g, respectively; p < 0.05), reflecting progressive microbial reduction through acidification and thermal treatment, whereas yeast counts remained stable across stages. Firmicutes dominated the fermented stages, with Lactococcus and Lactobacillus as the predominant genera. Whey harbored an exceptionally high abundance of Acetobacter (21.6%), highlighting its valorization potential. Factory-scale production yielded the lowest mold and coliform counts in finished products despite higher initial coliform levels in industrial raw milk, reflecting the effectiveness of standardized hygiene management. In contrast, workshop-scale samples exhibited a higher relative abundance of environmental indicator bacteria, suggesting a comparatively elevated contamination risk this intermediate production scale. PICRUSt2-based functional predictions indicated stage-specific metabolic potential, including predicted enrichment of pyruvate and fatty acid metabolism in yogurt, amino acid metabolism in whey, and vitamin B6 metabolism in hurood. These findings provide a systematic microbial baseline for hurood, identify scale-specific microbiological risk profiles, and offer a foundation for targeted hygiene control and standardized production strategies. Full article

Immunoglobulins exhibit important biological functions, including the neutralization of cytotoxins, enhancement of phagocytic activity, and activation of the complement system, which have driven their widespread application in both the food and pharmaceutical industries. Due to their low cost and short production cycles, microbial expression systems such as bacteria and yeast have been increasingly developed in recent years for immunoglobulin production. However, microbial systems face considerable challenges in ensuring proper protein folding, accurate chain assembly, and the soluble expression of full-length immunoglobulins. Recent optimization strategies have focused on host engineering (e.g., modulating secretion pathways and chaperone proteins), the coordinated regulation of expression elements (e.g., optimizing the light-to-heavy chain ratio), and regulation of fermentation processes. In addition to summarizing the above strategies, this review discusses the progress made in expressing both full-length immunoglobulins and antibody fragments across different microbial hosts, analyzes the advantages and limitations of each system, and explores potential future directions, aiming to provide a reference for the efficient heterologous expression of immunoglobulins. Full article

Pineapple glutinous rice wine is a popular fermented beverage, yet its flavor and quality remain highly affected by yeast strains. This study aimed to explore the effects of four commercial yeasts, namely La Raffinée (Ra), La Bayanus (Ba), La Délicieuse (De), and Angel wine yeast (AWY), on the quality of pineapple glutinous rice wine. Fermentation indices including Brix and alcohol content were dynamically monitored, while final wine samples were analyzed for color difference, sensory quality and aroma components by gas chromatography–ion mobility spectrometry (GC-IMS). Results showed that all yeasts had optimal fermentation efficiency, sugar-to-alcohol conversion, physicochemical properties and sensory quality at an addition level of 0.2 g/L. The 0.2 g/L De group achieved the optimal overall quality with an alcohol content of 10.01% vol, the highest ester content (22.55%) and the lowest acid content (12.18%), presenting a balanced flavor, prominent pineapple aroma and refreshing taste. In contrast, Ba led to higher acidity and Angel wine yeast contributed to greater sweetness. Overall, 0.2 g/L De yeast effectively coordinated pineapple aroma and glutinous rice wine characteristics, providing a practical reference for optimizing the production and quality improvement of pineapple glutinous rice wine. Full article

In many industrial dairy products, yeasts are generally regarded as contaminants. However, in traditional fermented milks, they may contribute to distinctive sensory, technological, and functional properties through associations with bacterial partners, including lactic acid bacteria (LAB). Despite this, a structured synthesis of yeast–bacterium associations across fermented milk typologies is currently lacking. To address this gap, a PRISMA-informed literature search identified 42 studies across 24 traditional fermented milks reporting paired bacterial and fungal communities. A genus-level co-occurrence analysis was used to identify which yeast–bacterium pairs were most frequently co-detected across independently documented products. The main co-occurrence patterns selected for detailed bibliographical discussion were Kluyveromyces with Acetobacter and LAB, including Lactobacillus, Streptococcus, Lentilactobacillus and Lacticaseibacillus; Pichia with LAB; Saccharomyces with LAB, especially Lactobacillus; Kazachstania with Acetobacter; Candida with Leuconostoc and Enterococcus; and Geotrichum with Pseudomonas and Enterococcus. For the selected associations, possible interaction mechanisms and implications for sensory identity, technological potential, and microbiological safety were discussed by integrating evidence from milk co-cultures, controlled model systems, and related fermented foods. Overall, this review provides a structured synthesis of yeast–bacterium associations in traditional fermented milks and identifies candidate consortia for future experimental validation. Full article

The economic viability of second-generation (2G) bioethanol production depends on the availability of robust, multistress-tolerant yeast strains capable of withstanding harsh industrial conditions. This study investigates animal manure as a novel ecological niche for discovering such strains, as microbes in these environments naturally adapt to high organic loading and fluctuating temperatures. From eighty-six initial isolates, twenty-nine demonstrated superior xylose fermentation at 37 °C. Eight high-performing isolates (C2-1, B1-2, B1-6, B2-6, B2-8, G1-4, G1-5, and G2-4) exhibited exceptional tolerance to ethanol, high temperatures, and lignocellulosic-derived inhibitors (acetic acid, formic acid, furfural, and vanillic acid). Molecular identification classified isolate C2-1 as Pichia kudriavzevii and the remaining seven as Candida tropicalis. In synthetic media, C. tropicalis B2-8 produced up to 16.33 g/L of ethanol using xylose (60 g/L) as the sole carbon source. While the undetoxified, highly acidic sugarcane bagasse hydrolysate completely inhibited yeast growth, the industrial potential of these strains was successfully validated using the concentrated, undetoxified enzymatic hydrolysate derived from the acid-pretreated sugarcane bagasse solids, which contained 30.15 g/L glucose and 25.58 g/L xylose. P. kudriavzevii C2-1 achieved ethanol titers of 6.02 g/L and 5.71 g/L at 37 °C and 40 °C, respectively. The C. tropicalis strains outperformed P. kudriavzevii, yielding 6.12–6.35 g/L at 37 °C and maintaining 5.75–6.19 g/L at 40 °C. These findings underscore the potential of manure-derived yeasts as resilient biocatalysts. Although their fermentation yields remain relatively low and require further metabolic optimization, their ability to survive and ferment in this concentrated, undetoxified enzymatic hydrolysate at elevated temperatures makes them promising candidates for further development in high-temperature ethanol fermentation (HTEF), offering a potential pathway toward reducing cooling costs associated with 2G biorefineries. Full article