Abstract: In order to obtain insights into the fermentation mechanism of Nongxiangxing baijiu, this study employed metagenomics to analyze the dynamic succession and functional characteristics of the microbial community in the fermented grains (Jiupei). Results showed that microbial richness and diversity peaked on day 6 of fermentation and then gradually declined. The community structure exhibited clear temporal succession, divided into three stages: early (0–12 days), middle (18–24 days), and late (30–45 days). In the late stage, Acetilactobacillus became the dominant bacterial genus, with a relative abundance exceeding 92%. The abundance of Maudiozyma increased significantly as fermentation progressed. CAZy annotation revealed that glycoside hydrolase (GH) genes were the most abundant. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated broad microbial involvement in key metabolic pathways such as glycolysis, ethanol synthesis, acid metabolism, and ester synthesis. Pantoea, Bacillus, Aspergillus, Rhizopus, and Acetilactobacillus were identified as core functional contributors. Using metagenomics, this study systematically reveals the stage-specific succession patterns and metabolic foundations of the microbial community in Nongxiangxing baijiu jiupei. These findings provide a theoretical basis and data support for optimizing the production process and improving the quality of baijiu.

Key words: Nongxiangxing baijiu; Jiupei; microbial community; metagenomics; functional analysis