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

Abstract

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.

Systematic Review of Actinomycetes in the Baijiu Fermentation Microbiome

“…Fermented grains undergo three processes: cooling, stacking, and cellar fermentation. In the early stage of stacking fermentation, the FG microbiome contained 11.5% Thermoactinomyces [ 6 ].…”

“… Relative abundance heatmap of Thermoactinomyces and actinomycetes in DQ samples obtained from high-temperature Daqu (HTD), white Daqu (WDQ), yellow Daqu (YDQ), black Daqu (BDQ), low-temperature Daqu (LTD), Taiwanese Daqu (TWDQ), the Daqu-making process (DQMP), Yibin Daqu (YBDQ), 1-year-old pit mud (1aPM), first-grade Daqu (FGDQ), special-grade DQ (SGDQ), 0-day fermented grain (0DFG), Hongtudi distillery Daqu (HDQ), 5th fermentation round FG (5BDQ), M-type Daqu (MDQ), H-type Daqu (HDQ), Zhongxin Daqu(ZXDQ), Zhenjiu Daqu (ZJDQ), and Maotai DQ (MTDQ) [ 6 , 63 , 71 , 72 , 73 , 79 , 80 , 82 , 83 , 84 , 85 , 88 , 91 , 92 , 95 , 107 , 110 , 112 , 114 , 116 , 122 ]. …”

“…Baijiu production consists of four successive stages: (i) saccharification of the grain starch using DQ or Xiaoqu (XQ) as the starter culture; (ii) open solid-state fermentation; (iii) distillation to produce the final liquor product; and (iv) storage aging. The open saccharification fermentation results in a highly complex microbiome, with many interactions between species [ 6 , 7 ]. This huge microbial diversity is responsible for the unique flavor of Baijiu, which is distinct from those of other distilled liquors, such as whisky, vodka, and tequila, which are made by submerged fermentation [ 8 ].…”

Dynamic changes of microbial community structure and flavor compounds formation during Qingzhi compound-flavor Baijiu fermentation

“…The diversity and dynamic changes of microbial community structure in Baijiu fermentation can directly affect the yield and flavor of the products, which have brought great challenges to the regulation of Baijiu quality. Therefore, it is of great value to analyze the microbial community structure and their evolution rules in Baijiu fermentation for regulating the production process and improving the product quality (Zhang et al, 2021b;Zhao et al, 2022).…”

Changes in the microbial community structure during the digitally managed fermentation of medium-temperature Daqu

“…Chinese Baijiu plays a critical role in traditional Chinese culture (Liu & Sun, 2018). Daqu is a fermentation starter for Chinese Baijiu production (Zhao et al, 2022). The flavor substances and precursor substances in Daqu determine the aroma of the Baijiu (He et al, 2019).…”