Different functions can be provided by low temperature Daqu with different appearance features due to variations in the microbial community structure during fermentation

Appearance features serve as pivotal metrics for regulating the Daqu fermentation process and assessing its quality. Nevertheless, uncertainties persist regarding the variances in microbial community structure and potential functions during Daqu fermentation with distinct appearance features. Employing amplicon sequencing technology, this study scrutinized low-temperature Daqu sample groups (Y and C) exhibiting discernible differences in appearance features. The results elucidated that microbial alpha-diversity within the Y group aligned with fluctuations in temperature and moisture during LT-Daqu fermentation, a contrast observed in the C group. Concomitant beta-diversity and dominant microbial succession analyses revealed disparate microbial community structures between these groups. Co-occurrence network analysis indicated heightened microbial interconnectivity within the Y group. Compared with the C group, the Y group showcased a greater abundance of relevant genes in the Glycolysis/Gluconeogenesis pathway. T test analysis delineated markedly distinct microorganisms at various fermentation stages, with Streptomyces, Staphylococcus, and Saccharomycopsis enriched in the Y group, and Lactobacillus, Wickerhamomyces, and Aspergillus in the C group. This comprehensive investigations revealed the difference of microbial community structure and function of LT-Daqu with different appearance features, providing insights for refining fermentation procedures and quality evaluation. Moreover, it contributes to an enhanced understanding of fermentation mechanisms in analogous domains.