Analysis of Bacterial Communities and Prediction of Functions and Phenotypes in the Preparation of High Temperature Daqu Using Different Methods

To compare and analyze the similarities and differences in the bacterial community structure of high temperature Daqu prepared by artificial starter-making and mechanical starter-making, this study used Illumina MiSeq high-throughput sequencing technology to analyze the bacterial community composition of two types of high temperature Daqu samples, and predicted the genetic function and phenotype of the bacteria. Through α-diversity found that there was no significant difference in the diversity and richness of bacteria between artificial and mechanical starter-making samples (P>0.05). The β-diversity showed that there were significant structural differences between the two types of high temperature Daqu samples (P<0.01), and the difference of the bacterial flora of the mechanical starter-making samples was relatively smaller. The analysis of bacterial community structure showed that compared with artificial starter-making samples, the content of Lentibacillus from mechanical starter-making samples was significantly higher (P<0.001), while the content of Weissella, Brevibacterium and Pediococcus was relatively lower (P>0.05). Through LEfSe analysis, it was found that Thermoactinomycetaceae was the biomarker of foot bending, and Bacillaceae was the biomarker of mechanism bending. Through gene function prediction, it was found that compared with artificial starter-making, the signal transduction mechanism of the bacteria in the high-temperature Daqu prepared by mechanical starter-making was significantly higher, and the intracellular transport, secretion and vesicle transport were significantly lower (P<0.05). Through phenotype prediction, it was found that the content of gram-positive bacteria in the mechanical starter-making samples was more abundant (P<0.05), while the ability of oxidative stress tolerance in the artificial starter-making samples was stronger (P<0.05). It could be seen that there were significant differences in the bacterial flora structure between the artificial and mechanical starter-making Daqu, which further affected the function and phenotype of the bacteria. This study can provide basic theory and disciplinary basis for promoting the development of Maotai-flavor Baijiu starter-making samples technology.