Abstract:The high-throughput sequencing technology was used to study the bacterial community structure of Daqu (the medium-temperature Daqu and the high-temperature Daqu) and the workshop air, and explore the correlation between Daqu and air bacterial communities; at the same time, combined with environmental factors and the composition of Daqu bacterial communities, preliminary verification of environmental factors on Daqu microbial community relevance was performed. The results revealed that 33 bacterial genera were obtained from medium temperature Daqu and air, and the number of bacterial species showed an opposite trend to the change of fermentation temperature; 31 bacterial genera were obtained from high temperature Daqu and air, and the number of bacterial species showed a decreasing trend throughout the fermentation process. Principal component analysis showed that the composition of air bacterial communities in Daqu and workshop air at middle-temperature was basically similar in the early stage of fermentation (except the second stage in fermentation), the composition of the high-temperature Daqu bacterial community was similar throughout the fermentation process, and was similar to that of the workshop air bacterial community in the early fermentation stage. Redundant analysis showed that the 6 factors, including starch content, moisture, acidity, humidity, room temperature, and Daqu temperature, explained 57.41% of the species distribution of Daqu community. The Monte Carlo substitution test found that starch content, moisture and acidity are the main factors affecting the composition of Daqu bacterial community. The dynamic change rule and correlation of bacterial community between Daqu and air during Daqu fermentation were revealed, which provided an important reference for Daqu production and research in the future.
