Pure Culture and Ultra-high Deep Metagenomic Sequencing for Analysis of the Differences in Microbial Diversity of High Temperature Daqu from Two Distilleries in Maotai Town

In this study, the microbial diversity of high temperature Daqu from different distilleries in Maotai town was analyzed by the pure culture technique and macrogenomic sequencing. The results showed that a total of 212 Bacillus strains were isolated and identified including B. sonorensis (77 strains), B. licheniformis (39 strains) and B. amyloliquefaciens (19 strains). A total of 55 high-quality genomes were obtained by metagenomic binning, including 18 new strains suspected of being Bacillus sp., Lactobacillus sp. and Weissella sp.. The analysis of the microflora structure showed that the dominant bacteria in Daqu were Desmospora sp. 8437, B. sonorensis and B. amyloliquefaciens, and the relative abundance of B. sonorensis and B. amyloliquefaciens in Daqu from distillery A were significantly lower than that from distillery B (P < 0.05). The diversity and abundance of microorganisms in high temperature Daqu from distillery A were significantly lower than those in Daqu from distillery B (P < 0.05), and there was a significant difference in microflora structure between them. In terms of functions, the differential metabolic pathways with higher abundance in high temperature Daqu from distillery A were mainly related to the biosynthesis of amino acids, while those from distillery B was mainly related to the degradation of L-rhamnose. This study is of positive significance for improving the fermentation process and screening excellent strains in the future.