Search Results (1,300)

The low efficiency of the microbial gasification of coal limits the application of bio-coal bed methane technology. The co-fermentation of coal and biomass provides a new approach for improving the degradation rate of coal. In this study, a co-fermentation system comprising five different coal orders with five microalgae was constructed in the laboratory, and the methanogenic characteristics of coal–algae co-fermentation and its microbiological mechanism were systematically investigated in terms of gas production, soluble organic matter, and microbial community characteristics. The results showed that the combination of lignite and Nannochloropsis exhibited optimal methane production, with a methane yield of 26.43 mL/g coal. Biogenic methane yields for lignite–Porphyra and anthracite–Porphyra were 23.43 mL and 21.28 mL, respectively, demonstrating the potential for algae to enhance gas production even in high-rank coals. pH monitoring revealed that algal species played a critical role in the acidification process. Dunaliella caused a continuous pH decrease, reaching 3.76 by day 30, while Nannochloropsis maintained a neutral pH of 6.95, optimizing the fermentation environment. Significant differences in soluble organic matter were observed between the lignite and anthracite fermentation systems, with lignite systems producing more volatile fatty acids, including acetic and butyric acids. Microbial community analysis revealed that Methanosarcina, an acetic acid-utilizing methanogen, was dominant in lignite and anthracite systems, while Syntrophomonas played a key role in lignite–Nannochloropsis co-fermentation. These findings provide valuable insights into optimizing coal microbial gasification and selecting appropriate algal species to enhance methane production efficiency. Full article

Biohydrogen, a low-carbon footprint technology, can play a significant role in decarbonizing the energy system. It uses existing infrastructure, is easily transportable, and produces no greenhouse gas emissions. Four technologies can be used to produce biohydrogen: photosynthetic biohydrogen, dark fermentation (DF), photo-fermentation, and microbial electrolysis cells (MECs). DF produces more biohydrogen and is flexible with organic substrates, making it a sustainable method of waste repurposing. However, low achievable biohydrogen yields are a common issue. To overcome this, catalytic mechanisms, including enzymatic systems such as [Fe-Fe]- and [Ni-Fe]-hydrogenases in DF and electroactive microbial consortia in MECs, alongside advanced electrode catalysts which collectively surmount thermodynamic and kinetic constraints, and the two stage system, such as DF connection to photo-fermentation and anaerobic digestion (AD) to microbial electrolysis cells (MECs), have been investigated. MECs can generate biohydrogen at better yields by using sugars or organic acids, and combining DF and MEC technologies could improve biohydrogen production. As such, this review highlights the challenges and possible solutions for coupling DF–MEC while also offering knowledge regarding the technical and microbiological aspects. Full article

Sour beer production is strongly influenced by the choice of lactic acid bacteria (LAB), yet few studies have systematically compared strain-specific contributions under controlled kettle souring conditions. This study evaluated the fermentation performance and flavor-modulating potential of three LAB species—Lacticaseibacillus paracasei, Pediococcus pentosaceus, and Leuconostoc mesenteroides—in sour India Pale Ale (IPA) brewing. Growing assessments showed that P. pentosaceus exhibited the most rapid and stable proliferation, while L. mesenteroides required a longer adaptation period. Acidification trials demonstrated that L. paracasei achieved the lowest pH (3.26–3.43), contributing to intense sourness, whereas P. pentosaceus and L. mesenteroides yielded milder acidity (pH 3.41–3.65). Gas chromatography-mass spectrometry showed that P. pentosaceus and L. mesenteroides produced significantly higher levels of fruity and floral esters, including 2-pentanol propanoate, which was approximately 4-fold higher than in the control. Principal component analysis further distinguished the beers according to their volatile profiles. These findings highlight the strain-specific potential of LAB in sour beer brewing and provide practical guidance for flavor differentiation in craft beer production. Full article

This study examines the enhancement of dark sequential fermentation and photofermentation of organic solid waste using magnetite and substrate pre-treatment for hydrogen production within the context of transitioning to cleaner energy sources, particularly low-carbon hydrogen. Experimental dark fermentation and photofermentation apparatuses were used, utilizing microorganisms to decompose biomass at a mesophilic temperature (35 °C) of Organic Fraction of Municipal Solid Waste (OFMSW), inoculated with UASB sludge and enhanced with magnetite. A dosage of 120 mg/L of magnetite was the most effective, yielding an average value of 4144 mL H₂/gVS. Additionally, the analysis revealed that the levelized cost of hydrogen (LCOH) decreases as more organic waste is utilized, making biohydrogen production a sustainable option, reaching USD 5/kg of OFMSW. Ultimately, generating hydrogen from organic waste can help reduce greenhouse gas emissions and promote a cleaner energy matrix. Full article

Shubat, a traditional fermented camel milk from Kazakhstan, is renowned for its unique flavor and nutritional properties, though its volatile compound profile remains poorly characterized. In this study, headspace solid-phase microextraction coupled with comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (HS-SPME-GC×GC–ToFMS) was employed to qualitatively identify and semi-quantitatively analyze volatile metabolites in seven Shubat samples collected from four regions of Kazakhstan. Of the 372 volatile organic compounds initially detected, 202 were retained after screening, predominantly comprising esters, acids, alcohols, ketones, and aldehydes. Esters, acids, and alcohol were found to be the most abundant categories. Diversity analyses (α and β) revealed substantial variation across regions, likely influenced by Shubat’s rich and region-specific microbiome. An UpSet analysis demonstrated that 75 volatile compounds were shared among all samples, accounting for over 87% of the total volatile content, indicating a chemically stable core. These findings underscore the chemical complexity of Shubat and provide novel insights into its metabolite composition, thereby establishing a foundation for future sensory, microbial, and quality-related research. 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

Methane (CH₄) is the second largest greenhouse gas (GHG) after carbon dioxide (CO₂), and ruminant production is an important source of CH₄ emissions. Among the six types of livestock animal species that produce GHGs, cattle (including beef cattle and dairy cows) are responsible for 62% of livestock-produced GHGs. Compared to beef cattle, continuous lactation in dairy cows requires sustained energy intake to drive rumen fermentation and CH₄ production, making it a key mitigation target for balancing dairy production and environmental sustainability. Determining how to safely and efficiently reduce CH₄ emissions from dairy cows is essential to promote the sustainable development of animal husbandry and environmental friendliness and plays an important role in improving feed conversion, reducing environmental pollution, and improving the performance of dairy cows. Combined with the factors influencing CH₄ emissions from dairy cows and previous research reports, this paper reviews the research progress on reducing the enteric CH₄ emissions (EMEs) of dairy cows from the perspectives of the CH₄ generation mechanism and emission reduction strategies, and it summarizes various measures for CH₄ emission reduction in dairy cows, mainly including accelerating genetic breeding, improving diet composition, optimizing feeding management, and improving fecal treatment. Future research should focus on optimizing the combination of strategies, explore more innovative methods, reduce EME without affecting the growth performance of dairy cows and milk safety, and scientifically and effectively promote the sustainable development of animal husbandry. Full article

Objectives: The primary objective of this study was to investigate the effects of Macrococcus caseolyticus isolated from Chinese bacon on the quality of Chinese-style sausages. Methods: The physicochemical properties and volatile flavor compounds (VOCs) of sausages inoculated with M. caseolyticus at different concentrations (10⁵, 10⁶, and 10⁷ CFU/g) were investigated. VOCs were detected using gas chromatography–ion mobility spectrometry (GC-IMS). Results: The sausages inoculated with M. caseolyticus showed progressive decreases in Aw, total volatile base nitrogen (TVB-N), malondialdehyde and carbonyl content during fermentation compared to the control sausage. A total of 90 VOCs were identified based on GC-IMS analysis, including 20 esters, 17 aldehydes, 22 alcohols, 12 ketones, 5 acids compounds, and 14 other compounds. M. caseolyticus-inoculated sausages exhibited elevated levels in alcohols and aldehydes, while the content of ketones was reduced compared to the control sausage. Multivariate statistical analysis indicated the significant differences in volatile flavor profiles among the sample and control sausages. Notably, seven VOCs in sausages, including 1-octen-3-ol, isoamyl alcohol, heptanal, hexanal, methyl 2-methylbutyrate, ethyl isovalerate and 2-pinene, were identified as the key aroma compounds (ROAV ≥ 1). Conclusions: The fermented sausages inoculated with different concentrations of M. caseolyticus exhibited significant differences in VOCs. This study provides the support for employing M. caseolyticus to improve the overall quality and flavor profile of Chinese-style sausage. Full article

The escalating climate crisis and unsustainable waste management practices necessitate integrated approaches that simultaneously address energy security and environmental degradation. Hydrogen, with its high energy density and zero-carbon combustion, is a key vector for decarbonization; however, conventional production methods are fossil-dependent and carbon-intensive. This systematic review explores biowaste-to-hydrogen (WtH) technologies as dual-purpose solutions, converting organic waste to clean hydrogen while reducing greenhouse gas emissions and landfill reliance. A comprehensive analysis of different conversion pathways, including thermochemical (gasification, pyrolysis, hydrothermal, and partial oxidation (POX)), biochemical (dark fermentation, photofermentation, and sequential fermentation), and electrochemical methods (MECs), is presented, assessing their hydrogen yields, feedstock compatibilities, environmental impacts, and technological readiness. Systematic literature review methods were employed using databases, such as Scopus and Web of Science, with strict inclusion criteria focused on recent peer-reviewed studies. This review highlights hydrothermal gasification and dark fermentation as particularly promising for wet biowaste streams, like food waste. Comparative environmental analyses reveal that bio-based hydrogen pathways offer significantly lower greenhouse gas emissions, energy use, and pollutant outputs than conventional methods. Future research directions emphasize process integration, catalyst development, and lifecycle assessment. The findings aim to inform technology selection, policymaking, and strategic investment in circular, low-carbon hydrogen production. Full article

Fermented vinegars have been highlighted globally for their health benefits. The benefits can differ according to the type of vinegar; therefore, we investigated the differences of 15 grain (GV), 10 persimmon (PV), and 14 apple vinegars (AV) using integrated non-targeted and targeted metabolome analyses. We profiled non-volatile and volatile metabolites using gas chromatography time-of-flight mass spectrometry (GC-TOF-MS), ultra-high-performance liquid chromatography–orbitrap–tandem mass spectrometry, and headspace–solid-phase microextraction–GC-TOF-MS. Among the 132 identified metabolites, 73 non-volatile and 40 volatile metabolites showed significant differences across the three vinegar types. Amino acids, hydroxy fatty acids, phenolic compounds, aldehydes, pyrazines, and sulfides were abundant in GV. Some phenolic compounds, alcohols, and esters were abundant in PV, whereas carbohydrates, flavonoids, and terpenoids were abundant in AV, contributing to nutrients, tastes, and flavors. Bioactivity assays revealed that GV showed notable antioxidant activity, whereas PV and AV had the highest total phenolic and flavonoid contents, respectively. Through quantitative analysis, we revealed that acetic acid, propionic acid, butanoic acid, lactic acid, and alanine were major components in the three types of vinegar, although their composition was different in each vinegar. Our comprehensive qualitative and quantitative metabolite comparison provides insights into the differences among the three vinegar types, classified according to their raw materials. Full article

Using wheat flour milling (WFM) co-products in pig diets may reduce feed cost. Still, energy digestibility is lower for WFM co-products than for feed grains. Inadequate information exists about their fermentation characteristics and the relationship between digestible energy (DE) value and chemical characteristics or in vitro energy digestibility. The objectives were to (1) determine the chemical characteristics, in vitro and in vivo DE values, and energy digestibility of WFM co-products in growing pigs; (2) determine their in vitro microbial fermentation characteristics, and (3) establish relationships between in vivo DE value of WFM co-products and their chemical composition, fermentation characteristics, or in vitro digestibility values. Across Canada, 94 WFM co-products were sampled and characterized for their chemical composition and in vitro dry matter (DM) and energy digestibility using pepsin, pancreatin, and a multi-enzyme complex containing arabinase, β-glucanase, hemicellulase, xylanase, and cellulase. The in vivo energy, DM digestibility and DE value of 9 WFM co-products (2 shorts, 5 millrun, 1 middling, and 1 bran) were determined using a corn-based diet and 40 growing pigs in two periods to obtain 8 observations per diet. After in vitro digestion, the 9 WFM co-product samples were subjected to microbial fermentation using fresh fecal inoculum in a cumulative gas-production technique. The WFM co-products had a high content of crude fiber (up to 7.9% in shorts, 9.9% in millrun, 7.1% in middlings, and 12.0% in bran) and crude protein (CP; up to 27.8% in shorts, 20.0% in millrun, 22.1% in middlings, 15.9% in bran). The DE values ranged from 2.84 to 3.74 Mcal/kg DM among WFM co-products. Among chemical characteristics, neutral detergent fiber was the best predictor (R² = 0.81) for in vivo DE value, followed by crude fiber (R² = 0.78), and acid detergent fiber (R² = 0.72). The in vitro DE values predicted (R² = 0.80) in vivo DE values of 9 WFM co-products. Based on principal component analysis, total gas and short-chain fatty acid production varied among WFM co-products and was associated with the CP content of WFM co-products. In conclusion, WFM co-products contain high crude protein and have a high DE value for growing pigs but vary substantially in nutritional value. Full article

The present study develops and optimizes a jet-cutting encapsulation method using a laboratory-scale encapsulator to incorporate herbal dietary supplements into fermented milk products. Sodium alginate and pullulan were selected as core and coating polymers, respectively, after rheological screening demonstrated that 1% alginate (η ≈ 350–450 Pa·s at 22–25 °C) and 2% pullulan (η ≈ 400 Pa·s at 25–30 °C) provide a balance between atomization, shell integrity, and fluidity. Under optimized conditions, capsules of 1.00 ± 0.05 mm diameter and high sphericity (aspect ratio 1.08 ± 0.03) were produced. In vitro gastrointestinal simulation confirmed capsule stability in simulated gastric fluid (pH 2.0) and complete disintegration within 120 min in simulated intestinal fluid (pH 7.2). Inclusion of 8% (w/w) capsules in a fermented milk beverage preserved appearance, texture, flavor, and color while increasing viscosity from 2.0 to 4.0 Pa·s. Titratable acidity rose from 87 °T at 24 h to 119 °T at 120 h, with sensory quality remaining acceptable; substantial gas formation and excessive sourness occurred only after 168 h, defining a 5-day refrigerated shelf life. These findings demonstrate that the 1% alginate–pullulan capsule system successfully protects plant extracts during gastric transit and enables targeted intestinal release, while maintaining the sensory and rheological properties of the fortified fermented milk product. Full article

Pearl millet (Pennisetum glaucum L.) is a promising crop for silage production in the Cerrado biome, but its use is still limited, and the ideal age for ensiling has not been well defined. This study aimed to evaluate the ADRf 6010 pearl millet hybrid at four harvest ages for ensiling: 75, 85, 95, and 105 days after planting (DAP). Forage production (green and dry forage mass), chemical composition, and fermentation parameters were analyzed. Harvested forage was chopped into 2.0 cm particles and treated with a concentration of 1 × 10⁵ CFU/g (Colony Forming Units; Lactobacillus plantarum CNCM I-3736 and Pediococcus acidilactici CNCM I-4622) of fresh forage. Forage mass increased linearly with harvest age. At 105 days of growth, the crop yielded 65,980 kg/ha of fresh forage and 15,569 kg/ha of dry matter. The dry matter (DM) and neutral detergent fiber (NDF) concentrations also increased with advancing harvest age. The concentrations of crude protein (CP), non-fibrous carbohydrates (NFC), and in vitro dry matter digestibility (IVDMD) decreased with increasing harvest age before ensiling. In the silages, pH, ammoniacal nitrogen (NH₃-N), effluent loss, gas losses, and silage density decreased linearly, while DM recovery increased. With advancing harvest age, there was a positive linear increase in the concentrations of DM, NDF, and acid detergent fiber (ADF). On the other hand, CP, NFC, and IVDMD showed a negative linear trend. Based on the results, the ADRf 6010 pearl millet hybrid demonstrated high forage yield and favorable fermentative characteristics when harvested at different growth stages during the summer season. Advancing harvest age resulted in increased forage mass, dry matter content, and dry matter recovery, along with reduced fermentation losses such as effluents and gases. Although later harvests led to reductions in crude protein concentration and in vitro digestibility, these effects were compensated for by the higher dry matter yield per hectare and better preservation conditions. Thus, ADRf 6010 pearl millet is a promising crop for silage production under tropical conditions. Full article

Methane (CH₄), originating from ruminants, is a major source of greenhouse gas emissions in the agriculture industry. This study aimed to determine the potential of red seaweed Gracilaria lemaneiformis (G. lemaneiformis) as an anti-methanogenic feed additive for cattle. Three supplementation levels of seaweed (2%, 5%, and 10% of dry matter) were evaluated for their effects on gas production and rumen fermentation characteristics during 48 h in vitro fermentation. The results revealed a significant decrease in total gas production (TGP), CO₂, CH₄, ammonia nitrogen (NH₃-N), and volatile fatty acid (VFA) concentrations, with no differences in pH or dry matter disappearance (DMD). Notably, compared with the control group without seaweed, supplementation with 2% G. lemaneiformis effectively reduces CH₄ emissions by 27.5% (p < 0.05). Supplementation with 2% G. lemaneiformis decreased the abundance of methanogens g_norank_f_Methanomethylophilaceae, responsible for CH₄ generation, and increased the populations of bacteria (Kandleria and Succinivibrio) that compete with methanogens for substrates. Furthermore, upregulating the levels of 13(S)-HOTrE and 9(S)-HOTrE (polyunsaturated fatty acids) could inhibit methanogenic activity. Additionally, lower VFA concentrations will provide less raw materials for methane synthesis, thus further inhibiting methanogenesis. In summary, G. lemaneiformis, as a red seaweed with important economic value, can not only be applied to enhance marine carbon sinks but can also serve as a promising candidate for mitigating biomethane emissions in cattle. Full article

In response to the growing interest in natural cosmetic raw materials with antioxidant and moisturising properties, this study focuses on the use of dandelion leaves (Taraxaci folium) in the co-fermentation process involving selected strains of Saccharomyces cerevisiae and Lactobacillus rhamnosus MI-0272. The aim of the study was to develop an innovative method of co-fermentation of dandelion leaves using waste beet molasses and organic cane biomolasses as substrates to produce lactic acid (LA), which is the main component of fermented cosmetic raw materials (FCRMs). The scope of the research included the determination of antioxidant activity using the DPPH (AA-DPPH) and ORAC (AA-ORAC) methods, determination of total polyphenol content (TPC) using the Folin–Ciocalteu method, assessment of lipophilicity by measuring the log P partition coefficient, assessment of wettability (contact angle), and statistical analysis. The key results indicated that the developed method allows for up to a fivefold reduction in fermentation time, enabling the production of FCRMs with the highest antioxidant activity (AA-DPPH = 3.0 ± 0.1 mmol Tx/L (Trolox equivalents per litre); AA-ORAC = 0.55 ± 0.02 mmol Tx/L) and the highest polyphenol content (TPC = 3589 ± 25 mg gallic acid equivalents per litre (GA/L)), with LA content (determined by GC-MS) up to 37 g/L. In addition, the analysis of the relationship between lipophilicity and membrane wettability showed that the hydrophilic antioxidants contained in FCRMs (log P = −0.9) can accumulate in the aqueous layers of the epidermis, suggesting their potential local protective and antioxidant effects. The results obtained confirm the potential of the developed technology in the production of modern cosmetic raw materials with antioxidant properties. Further research should include qualitative and quantitative analysis of phenolic acids contained in FCRMs and evaluation of the effectiveness of cosmetic preparations containing FCRMs in vivo. Full article