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PROVIDER: PRJNA1304765 | ENA |
REPOSITORIES: ENA
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Project description:Highland barley liquor is a distilled spirit made from highland barley on the Tibetan Plateau, but its alcohol yield is limited by the high fiber content of the raw material. In the field of biomass resources, functional microorganisms are commonly used in pretreatment to degrade cellulose and other substances, improving fermentation output. In this study, we isolated the cellulose-degrading probiotic Lactobacillus delbrueckii GR-8 (CMCase 6.21 U/mL) from the traditional vegetable-based fermented food "Jiangshui" and applied biological pretreatment to the fermentation of highland barley liquor. During pretreatment, probiotics enhanced cellulase and amylase activities in the fermented grains, resulting in a 25% reduction in cellulose content and a 112% increase in free reducing sugar content. The pretreatment significantly altered the microbial community structure, enhancing microbial diversity. After distillation, alcohol yield increased by 3.5%, and total acid and ester contents rose by 25% and 23%, respectively. Pyrazine compounds increased by 1290%, while higher alcohols like nonanol, phenylethanol, and hexanol decreased. The treated liquor caused less harm to mice, who showed improved memory, motor skills, and lower oxidative liver damage. This study demonstrates that biological pretreatment enhances both fermentation and the quality of Chinese spirits.
2025-03-04 | GSE290678 | GEO
Project description:Biofuel production from lignocellulosic waste and residues is a promising option to mitigate the environmental costs associated to energy production. However, the difficulty to cost-effectively overcome lignocellulose recalcitrance hampers a widespread application of such bioprocesses. Through an integrated approach, we focused on the factors affecting cellulose reactivity and their impact on downstream fermentation. Three cellulosic manufactured materials were characterized in details: facial tissue, Whatman paper, cotton pads. The model mesophilic cellulolytic bacterium Clostridium cellulolyticum was used to study colonization and metabolic patterns during fermentation of these materials. Facial tissue was extensively colonized and exhibited the fastest degradation and the highest ethanol-to-acetate ratio. Comparing facial tissue fermentation to Whatman paper fermentation by label-free quantitative shotgun proteomics and statistical analyses, 187 proteins showed a different behavior; higher concentration levels were detected for many enzymes from the carbohydrate central metabolic pathway; distinct patterns of expression levels were observed for carbohydratases degrading cellulose and hemicellulose. Overall, lower degrees of polymerization, lower crystallinity index, and the presence of hemicelluloses could explain the higher biological reactivity and bioethanol production yields.
2017-01-30 | PXD001051 | Pride
Project description:Biological pretreatment with Trametes versicolor to enhance methane production from lignocellulosic biomass: a metagenomic approach
| PRJEB27282 | ENA
Project description:Volatile fatty acids (VFAs) production through anaerobic fermentation
| PRJEB5881 | ENA
Project description:Background: Lignocellulosic biomass is a promising renewable feedstock for the microbial production of fuels. To release the major fermentable sugars such as glucose and xylose, pretreatment, hydrolysis, and subsequent conditioning of biomass feedstock are needed. During this process, many toxic compounds are produced or introduced which subsequently inhibit microbial growth and in many cases the production titer and rate. An understanding of the toxic effects of compounds found in hydrolysate on the fermentation microorganism is critical to improving biofuel yields in the process. One of the inhibitory compounds is furfural, liberated from hemicelluloses, which strongly inhibits the cell growth and ethanol production especially from xylose. Zymomonas mobilis is a capable ethanologenic bacterium with high ethanol productivity and high levels of ethanol tolerance. The development of robust biocatalyst to tolerate the lignocellulosic pretreatment inhibitors is one of the key elements for economic biofuel production. Results: In this study, the molecular responses of Z. mobilis to furfural, one major pretreatment inhibitor, were investigated using transcriptomic approaches of chip-based microarray. Furfural shock time course experiment with 3 g/L furfural supplemented when cells reach exponential phase and stress response experiment in the presence of 2 g/L furfural from the beginning of fermentation were carried out to study the short and long-term effect of furfural on 8b physiological and transcriptional profiles. The presence and supplementation of furfural negatively affect 8b growth in terms of final biomass and the fermentation time. Transcriptomic studies indicated that the response of 8b to furfural is dynamic, complex and differences exist between short-term shock response and long-term stress response. However, the gene function categories are similar with most downregulated genes related to translation and biosynthesis, while the furfural-upregulated genes were mostly related to cellular processes of general stress response and energy metabolism. Conclusions: Similar to previous report that acetate inhibited the growth of Z. mobilis 8b in RM using glucose or xylose as carbon source, the existence or supplementation of another major hydrolysate inhibitor furfural also inhibited 8b growth with slowing the substrate utilization and ethanol production. The difference between carbon sources is more dramatic than that of the major hydrolysate inhibitors of both NH4OAc (GSE57553) and furfural (this study). Several gene targets have been selected for genetic studies with promising preliminary results.
2016-11-18 | GSE63540 | GEO
Project description:Hydrogen production by dark fermentation
| PRJNA347863 | ENA
Project description:Mixed culture cathodic xylose electro-fermentation for VFAs production
| PRJEB79100 | ENA
Project description:Caldicellulosiruptor saccharolyticus is an extremely thermophilic, gram-positive anaerobe which ferments a broad range of substrates to mainly acetate, CO2, and hydrogen gas (H2). Its high hydrogen-producing capacity make this bacterium an attractive candidate for microbial biohydrogen production. However, increased H2 levels tend to inhibit hydrogen formation and leads to the formation of other reduced end products like lactate and ethanol. To investigate the organismM-bM-^@M-^Ys strategy for dealing with elevated H2 levels and to identify alternative pathways involved in the disposal of the reducing equivalents, the effect of the hydrogen partial pressure (PH2) on fermentation performance was studied. For this purpose cultures were grown under high and low PH2 in a glucose limited chemostat setup. Transcriptome analysis revealed the up-regulation of genes involved in the disposal of reducing equivalents under high PH2, like lactate dehydrogenase and alcohol dehydrogenase as well as the NADH-dependent and ferredoxin-dependent hydrogenases. These findings were in line with the observed shift in fermentation profiles from acetate production under low PH2 to a mixed production of acetate, lactate and ethanol under high PH2. In addition, differential transcription was observed for genes involved in carbon metabolism, fatty acid biosynthesis and several transport systems. The presented transcription data provides experimental evidence for the involvement of the redox sensing Rex protein in gene regulation under high PH2 cultivation conditions. Overall, these findings indicate that the PH2 dependent changes in the fermentation pattern of C. saccharolyticus are, in addition to the known regulation at the enzyme/metabolite level, also regulated at the transcription level. Two conditions: low H2 partial pressure and high H2 partial pressure, both at steady state growth were harvested for a dye-flip microarray experimental design. Biological replicates were harvested for both conditions and combined prior to cDNA synthesis. Both conditions were labeled with cy3 and cy5 dyes allowing for a technical replicate of hybridization in addition to the biological replicates.
2013-08-28 | E-GEOD-40430 | biostudies-arrayexpress
Project description:Gas fermentation is emerging as an economically attractive option for the sustainable production of fuels and chemicals from gaseous waste feedstocks. Clostridium autoethanogenum can use CO and/or CO2 + H2 as its sole carbon and energy sources. Fermentation of C. autoethanogenum is currently being deployed on a commercial scale for ethanol production. Expanding the product spectrum of acetogens will enhance the economics of gas fermentation. To achieve efficient heterologous product synthesis, limitations in redox and energy metabolism must be overcome. Here, we engineered and characterised at a systems-level, a recombinant poly-3-hydroxybutyrate (PHB)-producing strain of C. autoethanogenum. Cells were grown in CO-limited steady-state chemostats on two gas mixtures, one resembling syngas (20% H2) and the other steel mill off-gas (2% H2). Results were characterised using metabolomics and transcriptomics, and then integrated using a genome-scale metabolic model reconstruction. PHB-producing cells had an increased expression of the Rnf complex, suggesting energy limitations for heterologous production. Subsequent optimisation of the bioprocess led to a 12-fold increase in the cellular PHB content. The data suggest that the cellular redox state, rather than the acetyl-CoA pool, was limiting PHB production. Integration of the data into the genome-scale metabolic model showed that ATP availability limits PHB production. Altogether, the data presented here advances the fundamental understanding of heterologous product synthesis in gas-fermenting acetogens.
2019-02-03 | GSE115837 | GEO
Project description:The implementation of a cost-effective lignocellulosic ethanol production requires developing efficient high gravity processes (i.e. working at high substrate concentrations). During the fermentation processes, the presence of high concentration of insoluble solids leads to lower glucose consumption rates, reduced ethanol volumetric productivities, and the accumulation of intracellular reactive oxygen species (ROS). Major repressed biological processes include cell cycle progression, trehalose and glycogen biosynthesis, DNA repair mechanisms, and certain genes involved in the general cell stress response. On the other hand, genes related to the glutathione, thioredoxin and methionine scavenging systems are induced.
2019-08-23 | GSE115460 | GEO