Deciphering the mechanisms underlying regional heterogeneity of high-temperature Daqu through integrated electronic...

High-temperature Daqu (HTD) is crucial for shaping the style of Moutai-flavor Baijiu, but its quality characteristics exhibit geographical and spatial heterogeneity, resulting in diminished typicity of products from non-core production regions. Therefore, this study employed multiphase detection techniques to analyze HTD samples from the typical region (Guizhou) and emerging region (Shandong), along with their surface and inner layers. Guizhou HTD possessed superior biochemical activity (especially on the surface) and higher response values for W1W, W2W, umami, and salty sensors. It also showed higher concentrations of key flavor compounds, such as pyrazines, acids, and alcohols. Targeted amplicon sequencing showed Kroppenstedtia, Thermoascus, and Thermomyces dominated all samples, but Guizhou HTD had greater microbial diversity and richness. Metagenomics indicated a higher proportion of bacteria in Guizhou HTD, represented by Kroppenstedtia eburnea and Oceanobacillus indicireducens, whereas fungi were more prevalent in Shandong HTD, with Paecilomyces varioti, Aspergillus chevalieri, and Rasamsonia emersonii as the dominant species. Functional annotation demonstrated that carbohydrate metabolism and amino acid metabolism were core biological functions of HTD, with gene abundances showing Guizhou > Shandong and inner > surface. Furthermore, species-enzyme contribution and metagenome-assembled genomes analyses confirmed that HTD exhibited functional redundancy at the ecological scale, yet the species responsible for these functions displayed regional specificity, explaining the phenotypic heterogeneity between Guizhou HTD and Shandong HTD. These findings highlight the pivotal role of the production region in HTD quality and offer insights for improving Moutai-flavor Baijiu flavor in non-core regions.