Decoding the core microbiota during liquor fermentation of sauce-aroma baijiu: Advances in the characteristics of core microbial communities and their regulatory strategies.

Sauce-aroma Baijiu, a traditional Chinese solid-state fermented liquor, owes its unique quality to the synergistic metabolism of core microbiota (bacteria, yeasts, molds) during stacking and cellar fermentation. However, previous studies have predominantly focused on high-temperature Daqu, leaving the core microbiota in fermented grains insufficiently characterized, particularly regarding their succession dynamics, functional attributes, and targeted regulatory approaches. Additionally, the complex interspecific interactions and environmental adaptation mechanisms of core microbiota remain unclear. This review systematically summarizes the identification, isolation approaches, and functional characterization of core microbial taxa (e.g., Bacillus spp., Lactobacillus spp., Saccharomyces spp., Pichia spp.) and their spatiotemporal distribution patterns. Core microbiota employ multi-level molecular strategies, including enhanced tricarboxylic acid (TCA) cycle activity, suppressed pentose phosphate pathway, and upregulated heat shock protein expression etc., to withstand thermal, acidic, and ethanol stresses. They drive enzyme production and flavor compound biosynthesis during multi-round fermentation, where intricate interspecific interactions and environmental forces collectively shape the unique chemical profile of sauce-aroma Baijiu. Furthermore, targeted regulatory strategies are proposed, with functional strain supplementation and synthetic consortia proven effective for improving base Baijiu quality. This study provides a theoretical and practical foundation for harnessing microbial resources, optimizing brewing processes, and promoting the standardization, digitization, and intelligent production of sauce-aroma Baijiu.