Project description:To study the characteristics of proteins in Chinese Chixiang-flavor Baijiu fermentation, a label-free quantitative proteomics approach was established to identify proteins in Jiuqu starter and fermented grains.
Project description:Fen flavor Baijiu needs two rounds of fermentation, which will obtain Dacha after initial fermentation and Ercha after secondary fermentation. The quality of Baijiu is closely related to the microbes within fermented grains. However, the bacterial diversity in Dacha and Ercha fermented grains of Fen flavor Baijiu has not been reported. In the present study, the structure and diversity of bacteria communities within fermented grains of Fen flavor Baijiu were analyzed and evaluated using MiSeq platform's HTS with a sequencing target of the V3-V4 region of the 16S rRNA gene. Through the analysis of physical and chemical indexes and electronic senses, the relationship between bacterial flora, organic acid, taste, and aroma in fermented grains was clarified. The results indicated that Lactobacillus was the main bacteria in Dacha, and the mean relative content was 97.53%. The bacteria within Ercha samples were Pseudomonas and Bacillus, mean relative content was 37.16 and 28.02%, respectively. The diversity of bacterial communities in Ercha samples was significantly greater than that in Dacha samples. The correlation between Lactobacillus and organic acids, especially lactic acid, led to the difference between Dacha and Ercha organic acids, which also made the pH value of Dacha lower and the sour taste significantly higher than Ercha. Lactobacillus was significantly positively correlated with a variety of aromas, which made Dacha the response value of aromas higher. In addition, Bacillus had a significant positive correlation with bitterness and aromatic compounds, which led to a higher response value of bitterness in Ercha and made it present an aromatic aroma. This study provides an in-depth analysis of the difference between different stages of Fen flavor Baijiu, and theoretical support for the standard production and improvement in quality of Fen flavor Baijiu in the future.
Project description:The metabolism and accumulation of flavor compounds in Chinese Baijiu are driven by microbiota succession and their inter-related metabolic processes. Changes in the microbiome composition during Baijiu production have been examined previously; however, the respective metabolic functions remain unclear. Using shotgun metagenomic sequencing and metabolomics, we examined the microbial and metabolic characteristics during light-flavor Baijiu fermentation to assess the correlations between microorganisms and their potential functions. During fermentation, the bacterial abundance increased from 58.2% to 97.65%, and fermentation resulted in the accumulation of various metabolites, among which alcohols and esters were the most abundant. Correlation analyses revealed that the levels of major metabolites were positively correlated with bacterial abundance but negatively with that of fungi. Gene annotation showed that the Lactobacillus species contained key enzyme genes for carbohydrate metabolism and contributed to the entire fermentation process. Lichtheimia ramosa, Saccharomycopsis fibuligera, Bacillus licheniformis, Saccharomyces cerevisiae, and Pichia kudriavzevii play major roles in starch degradation and ethanol production. A link was established between the composition and metabolic functions of the microbiota involved in Baijiu fermentation, which helps elucidate microbial and metabolic patterns of fermentation and provides insights into the potential optimization of Baijiu production.
Project description:To investigate MASH-associated changes in DNA-methylation, a genome-wide DNA methylation profiling of livers from healthy individuals compared to those with MASH was performed using the 850K MethylationEPIC BeadChip Array. Further differential methylation analysis allowed us to identify a MASH epigenetic signature. Both males and females were included in this cohort, consisting of 4 MASH patients and 3 healthy individuals.
Project description:The fermented and distilled Chinese alcoholic beverage strong flavor baijiu (SFB) gets its characteristic flavor during fermentation in cellars lined with pit mud. Microbes in the pit mud produce many key precursors of flavor esters. The over 20 year maturation time of natural pit mud have promoted attempts to produce artificial pit mud (APM) with shorter maturation time. However, knowledge on the molecular basis of APM microbial dynamics and associated functional variation during SFB brewing is limited, and the role of this variability in high quality SFB production remains poorly understood. We studied APM maturation in new cellars till the fourth brewing batch using 16S rRNA gene amplicon sequencing, real-time quantitative PCR and function prediction based on the sequencing results, and metaproteomics and metabolomics techniques. The results provide insight into global APM prokaryotic dynamics and their role in SFB production, which will be helpful for further optimization of APM culture technique and improvement of SFB quality.