Search Results (289)

This study investigates a rare case of liquid alcohol preserved in a glazed ceramic vase from the tomb of Li Jurou (AD 1226), Jin dynasty, Xi’an, China, to provide new insights into medieval brewing traditions. We employed a multi-proxy approach combining microfossil and isotopic analysis, experimental brewing with sorghum, and incorporated previously published proteomic data to illuminate its origin. Microfossil analysis revealed yeast cells and starch granules with damage patterns diagnostic of enzymatic saccharification and mashing, indicating the use of malted sorghum and wheat, alongside cooked rice and foxnut. The starch damage features observed in the archaeological sample are consistent with patterns documented in experimental beer brewing with sorghum and wheat/barley. Stable isotope analysis yielded a δ¹³C value of –18.5‰, consistent with mixed C₃ and C₄ inputs. Two-component isotopic modeling revealed that C₄ plant (likely sorghum) contributed 40–50% of the ingredients, with C₃ plants such as wheat, rice, and foxnut making up the remainder. These findings align with proteomic results identifying sorghum proteins in the liquid. The combined evidence distinguishes this beverage from qu-based fermentation and links it instead to li-type brewing, rooted in malted cereals and associated with ritual practices. This represents the earliest direct archaeological evidence of sorghum beer in China, highlighting both technological innovation and cultural adaptation in historical alcohol production. Full article

Cordyceps militaris (C. militaris) is a medicinal fungus renowned for its diverse therapeutic properties, largely attributed to bioactive compounds such as cordycepin, polysaccharides, adenosine, D-mannitol, carotenoids, and ergosterol. However, the production and composition of these metabolites are highly influenced by cultivation conditions, highlighting the need for systematic optimization strategies. This review synthesizes current findings on how nutritional factors—including carbon and nitrogen sources, their ratios, and trace elements—and environmental parameters such as oxygen availability, pH, temperature, and light regulate C. militaris metabolite biosynthesis. The impacts of solid-state fermentation (using grains, insects, and agro-industrial residues) and liquid state fermentation (submerged and surface cultures) are compared, with attention to their roles in mycelial growth, fruiting body formation, and secondary metabolite production. Special emphasis is placed on mixed grain–insect substrates and light regulation, which have emerged as promising methods to enhance cordycepin accumulation. Beyond summarizing advances, this review also identifies key knowledge gaps that must be addressed: (i) the incomplete understanding of metabolite regulatory networks, (ii) the absence of standardized cultivation protocols, and (iii) unresolved challenges in scale-up, including oxygen transfer, foam control, and downstream processing. We propose that future research should integrate multi-omics approaches with bioprocess engineering to overcome these limitations. Collectively, this review highlights both current progress and remaining challenges, providing a roadmap for advancing the sustainable, scalable, and application-driven production of bioactive compounds from C. militaris. Full article

Polyhydroxyalkanoate (PHA) bioplastics are produced from wastewater as a carbon recovery strategy. However, the tuneable characteristics of PHAs and wastewater biorefinery potential have not been comprehensively reviewed. The aim of this study is to review the main challenges and strategies for carbon recovery from wastewater feedstocks via PHA production, assessing potential target biopolymer applications. Diverse PHA-accumulating prokaryotes metabolize organic pollutants present in wastewater through different metabolic pathways, determining the biopolymer characteristics. The synthesis of PHAs using mixed microbial cultures with wastewater feedstocks derived from municipal, agro-industrial, food processing, lignocellulosic biomass processing and biofuel production activities are described. Acidogenic fermentation of wastewater feedstocks and mixed microbial culture enrichment are key steps in order to enhance PHA productivity and determine biopolymer properties towards customized bioplastics for specific applications. Biorefinery of PHA copolymers and extracellular polysaccharides (EPSs), including alginate-like polysaccharides, are alternatives to enhance the value-chain of carbon recovery from wastewater. PHAs and EPSs exhibit a wide repertoire of applications with distinct safety control requirements; hence, coupling biopolymer production demonstrations with target applications is crucial to move towards full-scale applications. This study discusses the relationship between the metabolic basis of PHA synthesis and composition, wastewater type, and target applications, describing the potential to maximize carbon resource valorisation. Full article

The black soldier fly (Hermetia illucens) has become one of the most promising alternative protein sources in the feed and food industry. The aim of this work was to utilize microbial fermentation to enhance the nutritional properties of black soldier fly larvae (BSFL) as a food ingredient for human consumption by optimizing the amino acid profile and small peptide content. Free amino acids (FAA) have a critical role in human nutrition and bioavailability. Unlike whole proteins that require enzymatic breakdown in the digestive tract, FAA are directly absorbable by the small intestine, allowing for rapid utilization in protein synthesis and metabolic functions. BSFL pastes were fermented using Lacticaseibacillus paracasei (PCB 030) or a mixed starter culture preparation, and results were compared to pea protein and BSFL pastes that were enzymatically hydrolyzed. The resultant hydrolyzed BSFL pastes were analyzed for free amino acids and small peptides. The L. paracasei PCB 030 fermented BSFL pastes yielded significantly higher amounts of free amino acids than the control or pastes fermented using a commercial starter culture (named F-LC). The increased FAA availability in fermented BSFL makes it a more efficient protein source for human consumption. The L. paracasei PCB 030 fermented pastes showed an increase in small peptides after three days fermentation; nearly 80% of normalized abundances of small peptides increased by over 100 times compared to day zero (before the fermentation started). Over 90% of these small peptides consisted of more than 50% hydrophobic amino acids, which may contribute to their antioxidant and antibacterial properties. This study provides a promising and industrially practical process for hydrolyzing BSFL protein to yield a functional protein hydrolysate with an enhanced nutritional profile. Full article

Microbial-enhanced oil recovery (MEOR) is a promising technology for oilfield development. To improve MEOR efficiency, two functional strains—Bacillus mucilaginosus ZZ-8 and Bacillus amyloliquefaciens ZZ-11—were isolated and purified. The growth characteristics, biosurfactant production, and crude oil emulsification performance of these strains were systematically evaluated through single-strain cultures and a co-culture system (ZZ-8: ZZ-11 = 1:1). The results demonstrated that the co-culture system exhibited superior growth and functional performance compared to monocultures. The cell-free supernatant significantly reduced oil–water interfacial tension, decreasing the contact angle from 53.56 ± 1.3° to 28.78 ± 0.82°, thereby enhancing crude oil detachment from rock surfaces and improving oil displacement efficiency. Gas chromatography (GC) analysis further confirmed the co-culture system’s pronounced degradation of long-chain alkanes (C17–C35). In oil sand washing experiments, the 1:1 mixed-strain fermentation broth achieved a crude oil elution rate of 84.39%, representing an 89.80% increase over uninoculated medium. This study not only validates the synergistic effect of the B. mucilaginosus–B. amyloliquefaciens co-culture system in enhancing oil recovery but also provides a theoretical foundation and innovative strategy for its practical application in MEOR technology. Full article

This study aimed to identify and evaluate yeasts and lactic acid bacteria (LAB) isolated from Mexican cocoa mucilage (Theobroma cacao) and coffee pulp (Coffea arabica) for their potential use as sourdough starter co-cultures to improve bread quality. Functional screens included assessments of amylolytic, proteolytic, and phytase activities, CO₂ production, acidification capacity, and exopolysaccharide (EPS) synthesis. Saccharomyces cerevisiae YCTA13 exhibited the highest fermentative performance, surpassing commercial baker’s yeast by 52.24%. Leuconostoc mesenteroides LABCTA3 showed a high acidification capacity and EPS production, while Lactiplantibacillus plantarum 20B3HB had the highest phytase activity. Six yeast–LAB combinations were formulated as mixed starter co-cultures and evaluated in sourdough breadmaking. The B3Y14 co-culture (LABCTA3 + YCTA14) significantly improved the bread volume and height by 35.61% and 17.18%, respectively, compared to the commercial sourdough starter, and reduced crumb firmness by 59.66%. Image analysis of the bread crumb revealed that B3Y14 enhanced the crumb structure, resulting in greater alveolar uniformity and a balanced gas cell geometry. Specifically, B3Y14 showed low alveolar regularity (1.16 ± 0.03) and circularity (0.40 ± 0.01), indicating a fine and homogeneous crumb structure. These findings highlight the synergistic potential of selected allochthonous yeast and LAB strains in optimizing sourdough performance, positively impacting bread texture, structure, and quality. Full article

In this study, we investigated the impact of two native strains of Starmerella bacillaris, used both in pure culture and in a co-inoculation with Saccharomyces cerevisiae, on the volatile profile of a chemically defined fermented model must. The focus of this study was the production of monoterpenes and sesquiterpenes and their potential sensory contributions. Geraniol and linalool were detected in all fermentations with Starmerella bacillaris, in ranges of 26.7–43.9 µg/L and 34.3–41.3 µg/L, respectively, independent of the inoculation strategy used. Both strains produced concentrations above their respective odour thresholds of 20 µg/L and 25.5 µg/L. Odour activity value (OAV) analysis confirmed that fermentations with Starmerella bacillaris, particularly under co-inoculation conditions, generated the highest OAVs for these monoterpenes. Citronellol was only detected in mixed fermentations, while nerolidol and farnesol isomers were produced in variable amounts, depending on the strain and inoculation strategy, at concentrations below the odour threshold. These findings demonstrate the ability of Starmerella bacillaris to facilitate de novo biosynthesis of linalool, geraniol, and sesquiterpenes during alcoholic fermentation—in the case of linalool and geraniol, at concentrations exceeding their respective odour thresholds—highlighting the biotechnological potential of these native strains to enhance aroma in wines, particularly those made from neutral grape varieties. Full article

Controlling dry matter intake (DMI) is one strategy to reduce feed costs and increase efficiency. Including fat at a high concentrate level can increase the energy density of diets fed to ruminants, thus reducing DMI further. Therefore, the objective of this study was to evaluate the effects on fermentation and nutrient digestion of including different fat sources when high-concentrate diets with high-fat inclusion are used under simulating precision feeding in continuous culture. We hypothesized that incorporating different fat sources into the aforementioned program can improve nutrient utilization without affecting rumen fermentation. Four treatments were randomly assigned to eight continuous cultures in a randomized complete block design and ran for two periods of 10 d. Diets included a high concentrate level (HC; 65% DM) with high-fat inclusion starting with a 3% basal level of fat in the diet as the control (0% added fat; CON) and 9% fat in the diet (6% added poultry fat, PF; 6% added coconut oil, CO; and (6% added soybean oil, SO). Data were analyzed using the MIXED procedure of SAS with repeated measures. The DM, OM, NDF, and ADF digestibility coefficients (dCs) were higher for PF and CO, followed by SO and then CON. Starch and FA dCs were higher for different fat sources than for the CON. The total VFA concentration was higher for CON. There was a reduction in acetate and propionate with different fat sources. The mean culture pH and NH₃N were the highest for CO, followed by PF, then SO, and CON. The protozoa population was higher for CON than for the other fat treatments, followed by CO, PF, and SO. These results suggest that simulated precision feeding using continuous culture fermenters with high-concentrate diets up to 65% and high fat up to 6% can improve nutrient digestion approximately to 15% with changes in fermentation rate and profiles. Full article

Fruit and sour beers are popular due to their unique sensory characteristics. Owing to changes in physicochemical parameters, mixed culture fermentation is a promising research area. The aim of the study was to evaluate how ethanol and lactic acid fermentation, combined with the addition of berry fruits during the beer production process, influence the physicochemical and sensory characteristics of sour fruit beers. Three worts differing in hopping system were produced: one classic sweet wort and two lacto-fermented. Strawberries or raspberries were added to the young beer. This research showed that acidification of wort, fruit addition, and limiting of hopping time had a positive effect on both technological and sensory characteristics. Despite pH differences, alcohol content in beers was similar (2.52–3.21% v/v). Production method influenced mainly lactic acid (0–2.30 g/L), pH (3.53–4.79), and glycerol (0.83–1.62 g/L) contents. Non-acidified beers had the highest dextrin (17.64–23.13 g/L) and glycerol (1.36–1.62 g/L) levels. The addition of strawberries increased phenolics (205.21–237.03 mg GAE/L), FRAP (0.82–1.17 mmol TE/L), and refreshment sensation, while raspberries mainly enhanced sensory atributes (colour, foam, fruitiness, aroma). Lactic fermentation did not show a clear effect on polyphenol content or antioxidant activity. The research offers practical insights into functional beer development, with its novelty of using mixed fermentation and fruit addition to shape characteristics. Full article

Fusarium oxysporum f. sp. cucumerium, a resilient saprophytic fungus, poses a significant risk to cucumber crops. The research investigated the suppressive impact of Bacillus velezensis dhm2 on this pathogen and the synergistic performance of its crude lipopeptide extract with synthetic fungicides. Strain dhm2 inhibited the pathogen by 52.27% in confrontation culture. Its fermentation supernatant showed peak activity at 4 h bacterial age and 60 h fermentation duration, while the crude lipopeptide extract had an EC₅₀ of 9.99 g L⁻¹. Among the six chemical fungicides, prochloraz exhibited the highest toxicity, with an EC₅₀ value of 0.03 μg mL⁻¹. In all mixed combinations of the crude lipopeptide extract and chemical fungicides, there existed synergistic mixing ratios, particularly with difenoconazole (volume ratio 7:3, synergistic ratio 5.88) and propiconazole (7:3, 3.41), as confirmed by Wadley tests. Pot experiments revealed that the combined use of the crude lipopeptide extract and difenoconazole controlled cucumber Fusarium wilt by 80.95%. The mixture showed the highest SOD (315.76 U g⁻¹ FW min⁻¹), POD (281.63 U g⁻¹ FW min⁻¹), and CAT (23.39 U g⁻¹ FW min⁻¹), with increases over single treatments. This study provides an eco-friendly strategy for managing cucumber wilt, advocating reduced fungicide use via synergistic formulations. Full article

Although beer fermentation has traditionally been carried out with Saccharomyces, the boom in craft brewing has led to the use of non-conventional yeast species for beer production. This group also includes non-Saccharomyces starters, which are commonly used in winemaking and which have different technological characteristics compared to standard representatives of the Saccharomyces genus. One of the important characteristics of the non-Saccharomyces group is the richer enzyme profile, which leads to the production of beverages with different taste and aroma profiles. The aim of this study was to investigate sweet and hopped wort fermentation with seven strains of active dry non-conventional yeasts of Lachancea spp., Metschnikowia spp., Torulaspora spp. and a mixed culture of Saccharomyces cerevisiae and Torulaspora delbrueckii. One ale and one lager active dry yeast strain were used as control strains. The extract consumption, ethanol production, degree of fermentation, pH drop, as well as the yeast secondary metabolites formed by the yeast (higher alcohols, esters and aldehydes) in sweet and hopped wort were investigated. The results indicated that all of the studied types of non-conventional yeasts have serious potential for use in beer production in order to obtain new beer styles. For the purposes of this study, statistical methods, principle component analysis (PCA) and correlation analysis were used, thus establishing the difference in the fermentation kinetics of the growth in the studied species in sweet and hopped wort. It was found that hopping had a significant influence on the fermentation kinetics of some of the species, which was probably due to the inhibitory effect of the iso-alpha-acids of hops. Directions for future research with the studied yeast species in beer production are presented. Full article

Coffee is one of the most widely consumed beverages worldwide, primarily due to the stimulating effects attributed to its caffeine content. However, excessive intake of caffeine results in negative effects, including palpitations, anxiety, and insomnia. Therefore, low-caffeine coffee has captivated growing consumer interest, highlighting its significant market potential. Traditional decaffeination methods often lead to non-selective extraction, resulting in a loss of desirable flavor compounds, thereby compromising coffee quality. In recent years, microbial fermentation has emerged as a promising, targeted, and safe approach for reducing caffeine content during processing. Additionally, mixed-culture fermentation further enhances coffee flavor and overcomes the drawbacks of monoculture fermentation, such as low efficiency and limited flavor profiles. Nonetheless, several challenges are yet to be resolved, including microbial tolerance to caffeine and related alkaloids, the safety of fermentation products, and elucidation of the underlying mechanisms behind microbial synergy in co-cultures. This review outlines the variety of microorganisms with the potential to degrade caffeine and the biochemical processes involved in this process. It explores how microbes tolerate caffeine, the safety of metabolites produced during fermentation, and the synergistic effects of mixed microbial cultures on the modulation of coffee flavor compounds, including esters and carbonyls. Future directions are discussed, including the screening of alkaloid-tolerant strains, constructing microbial consortia for simultaneous caffeine degradation for flavor enhancement, and developing high-quality low-caffeine coffee. Full article

Sourdough fermentation has emerged as a promising biotechnological approach to reducing gluten content and modifying gluten proteins in wheat-based products. This review assesses the current scientific literature on the enzymatic degradation and hydrolysis of gluten during lactic acid bacteria (LAB) sourdough fermentation. It explores implications for individuals with gluten-related disorders, including celiac disease, non-celiac gluten sensitivity and intolerance, as well as irritable bowel syndrome (IBS). In addition, LAB sourdough effect on fermentable oligo-, di-, monosaccharides and polyols (FODMAPs), amylase-trypsin inhibitors (ATIs), and phytate are revised. Selected homo- and heterofermentative LAB are capable of degrading gluten proteins, especially the polypeptides derived from the action of native cereal proteases. Mixed cultures of LAB degrade gluten peptides more effectively than monocultures. However, LAB sourdough is not sufficient to remove the toxic peptides to the minimal level (<20 ppm). This goal is achieved only if sourdough is combined with fungal proteases during sourdough fermentation. LAB sourdough directly contributes to lower FODMAPs but not ATIs and phytate. Phytate is reduced by the endogenous cereal phytases activated at acidic pHs (pH < 5.0), conditions generated during sourdough fermentation. ATIs are also lowered by endogenous cereal proteases instead of LAB proteases/peptidases. Despite LAB sourdough not fully degrading the gluten or directly reducing the ATIs and phytate, it participates through peptidases activity and acidic pH that trigger the action of endogenous cereal proteases and phytases. Full article

Ruminant livestock contribute significantly to methane emissions, necessitating sustainable mitigation strategies. Essential oils (EOs) show promise for modulating ruminal fermentation, but their synergistic effects remain underexplored. Two 24 h in vitro experiments evaluated the synergistic effects of EO blends on rumen microbial fermentation. Exp. 1 screened five oils using two triad combinations. Triad 1 tested 10 combinations of thyme (THY), peppermint (PPM), and cinnamon leaf (CIN) oils. Triad 2 tested 10 combinations of anise (ANI), clove leaf (CLO), and peppermint (PPM) oils. Each blend was tested at 400 mg/L, using batch culture methods measuring: pH, ammonia-N (NH₃-N), and volatile fatty acids (VFAs). The two most effective blends, designated as T1 and T2, were selected for Exp. 2 to assess total gas and methane (CH₄) production using pressure transducer methods. All treatments were incubated in a rumen fluid–buffer mix with a 50:50 forage-to-concentrate substrate (pH 6.6). In Exp. 1, data were analyzed according to the Simplex Centroid Design using R-Studio. In Exp. 2, an analysis was conducted using the MIXED procedure in SAS. Mean comparisons were assessed through Tukey’s test. The results from Exp. 1 identified CIN+PPM (80:20) and ANI+CLO (80:20) as optimal combinations, both increasing total VFAs while reducing acetate/propionate ratios and NH₃-N concentrations. In Exp. 2, both combinations significantly reduced total gas and CH₄ productions compared to the control, with CIN+PPM achieving the greatest methane reduction (similar to monensin, the positive control). Specific essential oil combinations demonstrated synergistic effects in modulating rumen fermentation and reducing methane emissions, offering potential for sustainable livestock production. Further in vivo validation is required to optimize dosing and assess long-term effects on animal performance. Full article

The robust structure of algal cell walls presents a major barrier in the recovery of fermentable sugars and intracellular lipids for biofuel production. This study investigates the effectiveness of ultraviolet (UV) radiation and UV-assisted hydrogen peroxide (UV/H₂O₂) pretreatment on a local mixed marine algal culture to enhance biofuel production through cell wall disruption. Local mixed cultures of marine microalgae (LMCMA) were pretreated with UV for various exposure times (5–30 min) and with UV/H₂O₂ using H₂O₂ concentrations ranging from 0.88 to 3.53 mM. The impact of pretreatment was evaluated based on morphological changes (SEM and TEM), elemental composition (C, H, N), sugar release, and downstream fermentation yields of ethanol, methanol, 1-propanol, 1-butanol, and 1-pentanol using Saccharomyces cerevisiae. UV pretreatment at 20–30 min yielded the highest carbohydrate release (up to 0.025 g/gDCW), while UV/H₂O₂ at 1.76 mM achieved maximum sugar liberation (0.0411 g/gDCW). Fermentation performance was enhanced under optimized conditions, with peak ethanol yields of 0.3668 g ethanol/g carbohydrates (UV, 30 min, 48 h) and 0.251 g ethanol/g (UV/H₂O₂, 0.88 mM, 24 h). This study also demonstrated selective production of higher alcohols under varying fermentation temperatures (30–37 °C). These findings highlight the potential of combining oxidative pretreatment and process optimization to enhance biofuel recovery from environmentally relevant algal biomass. Full article