Seasonal changes driving shifts in core microbes of Nongxiangxing Daqu: a integrated multi-omics analysis and deep...

Core microorganisms play a crucial role in determining the quality of Daqu (a fermentation starter), and their identification and regulation are vital for further controlling the quality of Daqu and Baijiu. Therefore, this study revealed the flavor dynamics and microbial succession in Daqu under seasonal and pressing pattern variations and based on these, the core microorganisms and community assembly were revealed by integrating high-throughput sequencing with deep learning. Physicochemical properties and flavor compounds analysis of 120 Daqu samples revealed that Daqu produced in spring exhibited higher enzyme activity, diversity and abundance of esters and pyrazines. Moreover, methyl stearate and 2-undecanone were identified as the differential flavor compounds distinguishing Daqu produced in different seasons. The dominant bacteria were all associated with heat-tolerant microorganisms and acidity-related microorganisms like Bacillus, Thermoactinomyces, Staphylococcus and Weissella, and the fungi were mainly composed of Thermoascus and Thermomyces in all seasons. The core microorganisms of Daqu produced in different seasons were revealed by an investigation of interactions among microbes, physicochemical properties, and flavor compounds and validated through a data-driven keystone species identification (DKI) framework. Geotrichum and Clavispora were identified as core microorganisms independent of seasonal variations and pressing patterns. Further analysis based on βNTI and RC_bray was employed to investigate the community assembly process of Daqu and the results indicated that stochastic drift consistently dominated community assembly during seasonal variations. These findings may offer scientific guidance for optimizing the production of Nongxiangxing Daqu in different season, and subsequently enhancing the quality of Daqu.