Abstract: In this study, the structure and diversity of microbial community in Jiang-flavor Daqu processed using highland barley, purple wheat or pure wheat as raw material under the same conditions were analyzed using the Illumina platform, and intergroup separation was investigated and marker microorganisms were identified by multivariate statistical analysis. The results showed that Ascomycetes, Firmicutes, and Actinomycetes were the absolute dominant phyla in each of the three Daqu samples. The bacterial community in pure wheat Daqu (XMQ) was dominated by the genera Kroppenstedtia, Virgibacillus, Lactobacillus, and Weissella. The bacterial community in purple wheat Daqu (ZMQ) was dominated by the genera Kroppenstedtia, Virgibacillus, uncultured_bacterium_f_Bacillaceae, Bacillus, and Scopulibacillus. The bacterial community in QKQ was dominated by Lactobacillus, Weissella, and Thermoactinomyces. Thermoascus and Debaryomyces were dominant fungal genera in all samples. Meanwhile, Byssochlamys, Monascus, Kazachstania, and Torulaspora were dominant fungal genera in XMQ. Monascus, Aspergillus, and Rasamsonia were dominant fungal genera in ZMQ. Kazachstania, Torulaspora, and Thermomyces were dominant fungal genera in QKQ. In addition, principal component analysis (PCA), hierarchical cluster analysis (HCA), and orthogonal partial least squares discriminant analysis (OPLS-DA) revealed a clear separation between the three Daqu samples, and out of the dominant genera, 10 significantly differential bacterial genera and nine significantly differential fungal genera were obtained by linear discriminant analysis as key biomarkers to discriminate among Daqu produced from different raw materials. The results of this study lay a theoretical foundation for the quality improvement of Jiang-flavor Daqu.

Key words: Jiang-flavor Daqu; raw materials; high throughput sequencing; microbial diversity; multivariate analysis; linear discriminant analysis effect size