Abstract: In this study, high-throughput sequencing was used to analyze the bacterial community structure during the fermentation of Chinese light/sauce-flavored liquor. A total of 14 phyla and 113 genera were detected in the fermented grains. At the beginning of fermentation, Firmicutes, Proteobacteria and Cyanobacteria were dominant with an average relative abundance of higher than 10%. As the fermentation progressed, Firmicutes gradually evolved into the only dominant bacterium. The top 10 most abundant bacterial genera during the fermentation process were Lactobacillus, Bacillus, Weissella, Acetobacter, Gluconobacter, Pediococcus, Kroppenstedtia, Staphylococcus, Enterobacter, and Scopulibacillus. The bacterial community finally evolved to be dominated by Lactobacillus only. In order to explain the sources of bacteria in the fermented grains during thin-layer stacking fermentation, the bacterial community structure in koji was analyzed. Samples without adding koji was set as a control. The bacterial community structure in the fresh and fermented grains as well as the control sample was further analyzed. The results showed that 31.67% of the bacterial genera in the fermented grains came from the environment, 50% from koji, 23.33% from both koji and the environment, and only 5% from the environment. The dominant bacterium Gluconobacter was exclusively from the environment. This study will help in understanding the microecology of bacteria involved in liquor fermentation, which is of great significance to improve the quality, safety and controllable production of liquor.

Key words: light/sauce-flavored liquor; high-throughput sequencing; community structure; stacking; source of bacteria