Diversity, Community, and Function of Lactic Acid Bacteria in the Brewing of Strong-Flavor Baijiu: A Review

Lactic acid bacteria (LAB) are the core functional microbes in strong-flavor Baijiu brewing. Through lactate metabolism, they maintain the ecological balance of the fermentation pit, regulate the synthesis of organic acids and esters, and thus critically influence flavor compound formation and quality stability. Current research focuses on screening functional LAB strains and analyzing fermentation mechanisms and metabolic networks, yet challenges remain regarding complex species lineage, unclear ecological interaction mechanisms, and difficulties in dynamic regulation. This review summarizes LAB diversity in the brewing system, their metabolites and regulation, community interaction networks, niche advantages, and diversified applications. Specifically, it investigates LAB species in distinct ecological niches such as fermented grains (Jiupei), pit mud, and Daqu; clarifies metabolic pathways and products and their associations with flavor substances; and evaluates dynamic changes in LAB during brewing and interactive mechanisms with other fermentative microorganisms. In addition, the review presents findings on probiotic functions of LAB, their applications in food preservation, and their roles in environmental protection, and proposes future research directions. The aim is to provide novel insights for functional utilization of LAB in the brewing system and quality enhancement of Baijiu, as well as a reference for broader and diversified applications.