Multi-omics characterization of new and aged Daqu reveals region-specific microbial succession and metabolic signatures in Maotai-flavor liquor fermentation

ABSTRACT Daqu is an essential fermentation starter that drives the formation of the characteristic flavor of Maotai-flavor liquor, yet the ecological and metabolic mechanisms underlying its regional differentiation and maturation remain poorly resolved. Here, we performed genome-resolved metagenomic and untargeted metabolomic analyses on 48 new and aged Daqu samples collected from four major Maotai-flavor liquor-producing regions in Guizhou Province, China. We reconstructed 163 high-quality metagenome-assembled genomes (MAGs) spanning 16 bacterial and 3 archaeal phyla and identified 2,642 metabolites across ionization modes. Distinct regional microbial signatures were observed, with Jinsha Daqu showing the greatest genomic diversity and unique MAGs, whereas Maotai Daqu exhibited the highest community similarity with other regions. Aged Daqu significantly increased microbial richness and functional capacity, enriching thermophilic and spore-forming taxa (e.g., Bacillus , Lentibacillus , Kroppenstedtia ) and enhancing carbohydrate-active enzymes (GH13, GH43, and GH3), amino acid degradation, lipid metabolism, and secondary metabolic pathways. Metabolomic profiling revealed elevated amino acid derivatives, fatty acids, esters, and phenolic compounds in aged Daqu, indicating intensified biochemical activity. Multi-omics integration linked dominant microorganisms—including Bacillus thuringiensis , Actinomycetaceae bacterium, and Methylocaldum szegediense to pyrazine biosynthesis, amino acid catabolism, and lipid oxidation, forming coordinated microbial–metabolite modules that underlie region-specific flavor precursor formation. These findings establish a mechanistic model in which microbial terroir, aging-driven succession, and metabolic specialization jointly shape the maturation and flavor potential of Maotai-flavor liquor. IMPORTANCE This study provides the first genome-resolved, multi-omics framework for understanding how geographic origin and storage aging co-regulate the ecological assembly, functional specialization, and metabolic transformation of Maotai-flavor liquor. By linking specific MAGs, functional pathways, and key flavor precursors, our results offer mechanistic insights into microbial terroir and provide a scientific foundation for microbiome-guided optimization of Maotai-flavor liquor quality.