High throughput sequencing of the bacterial composition and dynamic succession in Daqu for Chinese sesame flavour liquor

Sesame flavour liquor is a traditional Chinese distilled spirit with fruity, sweaty, roasted sesame and floral aromas. High temperature Daqu production is one of the key processes in the formation of sesame flavour liquor. The composition and changes in the microbial community during the making of Daqu have a significant impact on the quality of Daqu liquor. In this study, microbial diversity based on high throughput sequencing technology was used to reveal the bacterial community structure and succession law in the four critical stages of high temperature Daqu production. The results show that Firmicutes had a significant advantage (76.7%-98.2%) in the four stages as Proteobacteria and Actinobacteria reached peak values in the first and second periods, and decreased in the later periods. At the genus level, Kroppenstedtia, Lactobacillus, Weissella, Lentibacillus, Bacillus and Saccharopolyspora were detected as the main bacterial groups in the high temperature Daqu of Chinese sesame flavour liquor. The abundance of Lactobacillus and Weissella was greater than that of other microbes in the Daqu entry period. During the first Daqu flipping, the number of bacterial genera reached a peak in the production process. Then, the bacterial diversity continued to decrease until the last period, while Kroppenstedtia, Saccharopolyspora and Lentibacillus adapted to the high temperature environment and accumulated during the second Daqu flipping and the Daqu exit. This research used high throughput sequencing technology to reveal, for the first time, the bacterial composition and dynamic succession in high temperature Daqu production of Chinese sesame flavour liquor. This work will contribute to a deeper understanding of the correlation between the formation of flavour substances in sesame flavour liquor and the microorganisms used in its production. (C) 2019 The Institute of Brewing & Distilling