Abstract: In order to further analyze the complex microbial system during the traditional solid-state fermentation process of Moutai-flavor Baijiu, we investigated the bacterial community structure in fermented grains from the first round of pile and pit fermentation by high-throughput sequencing technology. The results showed that the diversity and richness of bacteria during pile fermentation were higher than those during pit fermentation. After the start of pit fermentation, the diversity and richness of bacteria showed a sharp decline. At the phylum and genus levels, the species of total bacteria, major bacteria and dominant bacteria during pile fermentation were more than those during pit fermentation, and after the start of pit fermentation, rapid microbial community succession occurred from the complex structure containing multiple bacteria to a homogenous one dominated by Lactobacillus. There were 13 dominant genera during pile fermentation, including Lactobacillus, Escherichia-Shigella and Bacillus. The dominant genus during pit fermentation was Lactobacillus. There were significant positive correlations among the top 25 most abundant genera during pile and pit fermentation. The inhibitory effect of Lactobacillus on other bacteria was stronger during pile fermentation than during pit fermentation. The results of this study lay a scientific foundation for understanding the mechanism of the traditional solid-state fermentation of Baijiu and promoting industrial development.

Key words: Moutai-flavor Baijiu; high-throughput sequencing; pile fermentation; pit fermentation; bacterial community structure