Elucidating the physicochemical parameters, bacterial community structure, and correlation characteristics of medium-high temperature Daqu

In this study, the physicochemical characteristics and bacterial community structure of Yunmen medium-high temperature Daqu were investigated. At the same time, the bacterial community structures of medium-high temperature Daqu from Yunmen and Yingtan were compared and analyzed. The results showed that Yunmen medium-high temperature Daqu was rich in culturable bacteria, and the highest number of Bacillus amyloliquefaciens (33.33 %). The moisture content (8.28 % ± 0.62 %) of Yunmen medium-high temperature Daqu was low, but its acidity (9.26 ± 2.08 mmoL/10 g) and starch content (66.20 % ± 2.80 %) were high, which were related to the relative abundance of Latilactobacillus, Companilactobacillus, Weissella, and Bacillus. Compared with Yingtan medium-high temperature Daqu, the significantly lower Shannon index and Simpson index (P < 0.05); the weaker correlation between bacterial networks, especially positive correlation; and the lower relative abundance of core bacterial communities of Yunmen medium-high temperature Daqu. Overall, this study evaluated the quality of Yunmen medium-high temperature Daqu and revealed the bacterial community structure of medium-high temperature Daqu from two different regions. The results could guide the future exploration of fermentation mechanisms in medium-high temperature Daqu.