Analysis of dominant microorganisms and core enzymes in Qingke Baijiu Daqu by high-throughput sequencing and proteomics

Daqu plays a crucial role in Qingke Baijiu production by providing essential raw materials, microorganisms, and enzymes for fermentation. In order to further investigate the impact of microorganisms and enzymes in Qingke Baijiu Daqu, the physicochemical properties, dominant microorganisms, as well as enzyme system composition of Qingke Baijiu Daqu were studied. The results revealed 8 dominant bacterial genera and 4 dominant fungal genera in Daqu. Through the analysis of metaproteomics, 422 enzyme proteins were identified, including 121 oxidoreductases, 108 transferases, 74 hydrolases, 33 lyases, 41 isomerases, 32 ligases and 13 translocase. The activity of key enzymes in the main metabolic pathways of Daqu was measured, and it was found that the activity of saccharifying enzyme was the highest, which was the primary hydrolase of Daqu. Finally, correlation analysis showed that Erwinia was positively correlated with saccharification power. This study can provide valuable insights for controlling the quality of Daqu and Qingke Baijiu.