Linking microbial ecosystem to key flavor compounds in high-temperature Daqu: Multi-omics insights into Bacillus-driven acetoin-pyrazine pathway

High-temperature Daqu (HTD) is critical for Jiangxiang-type Baijiu (JXBJ), as its complex microbial community and metabolic activities directly determine the flavor quality and typicality of the final product. However, existing studies have largely focused on single manufacturers or limited omics approaches, leaving the interactive effects of production process, manufacturer origin, and Daqu color on microbial communities and flavor compounds poorly understood. This study employed an integrated multi-omics approach to analyze multiple HTD samples from three major manufacturers in Maotai Town, representing different production processes (traditional vs. mechanical) and Daqu colors. Shotgun metagenomics identified Firmicutes as the dominant phylum, with traditional Daqu exhibiting higher microbial richness than mechanical Daqu , attributed to longer fermentation cycles and increased environmental exposure. GC-MS detected 122 VOCs across 10 classes, with esters and pyrazines as dominant categories; tetramethylpyrazine, a key aroma contributor, was most abundant in traditional Daqu . Functional annotation highlighted carbohydrate and amino acid metabolism as core pathways, while redundancy analysis confirmed positive correlations between Bacillus species and pyrazines. By investigating effects of manufacturer origin, production process, and Daqu color on microbial-flavor interactions through multi-omics analysis, this study fills a critical knowledge gap, offering a basis for optimizing production parameters and enhancing JXBJ quality consistency.