Community diversity and succession in fermented grains during the stacking fermentation of Chinese moutai-flavored liquor making

As an indispensable and crucial part of the Moutai-flavored liquor production process, stacking fermentation facilitates the accumulation of various microbiota as microbial materials in fermented grains used for liquor making. The diversity of and dynamic changes in highly complex microbiota during this fermentation phase were investigated by characterizing microbial communities through high-throughput sequencing with an Illumina PE300 platform. Through community composition and differentially abundant analyses, 12 key bacteria and 12 key fungi were identified, which contributed to major variations in community succession. Bacillus and Saccharomyces were overrepresented in the bacterial and fungal communities, respectively. In addition, differentially abundant analyses showed that the key microbiota were mainly structured from the early period to the middle period of fermentation and functional populations showed a large accumulation in later periods. Further, endogenous factors showed changing trends, and their potential correlations and varied interactions with the key microbiota were explored through PLS-DA modeling. All the findings in the current study enhances knowledge of complex key microbiota in stacking fermentation and provides theoretical support for optimizing microbial structures through the regulation of endogenous factors and improving fermentative quality.