Metagenomic insights into quorum sensing-associated microbial profiling and its correlations with flavor compounds of Maotai-flavor liquor: A case study of stacking fermented grains.

Stacking fermentation is typical process of Maotai-flavor Baijiu and microbial composition determine content of flavors. To date, the knowledge on the driving force of microbial composition was as yet unknown. Since quorum sensing molecule (QSM) plays an important role in modifying microbial interactions. Therefore, the objectives of the present study were: (1) to describe the microbial profile associated with QSM in stacking grains using metagenomics; (2) to elucidate how QSM shapes microbial interactions and accordingly regulates flavor synthesis. Results indicated that bacterial QSM including AI-2, DSF, and AHL as well as fungal QSM aromatic alcohols and farnesol were prevalent in the stacking fermented grains. Thereinto, AI-2 might be an important driving force of microbial composition due to its highest abundance. AI-2 in Limosilactobacillus fermentum, Pediococcus pentosaceus, and Weissella cibaria perhaps modified microbial interactions together with fungal QSM in Schizosaccharomyces pombe and Pichia membranifaciens. The role of AI-2 was much higher than that of fungal QSM. Furthermore, QSM indirectly influenced the synthesis of important flavors such as ethyl lactate, phenylethanol, and ethyl phenylacetate through the dynamic of microbial composition. Together, this current study for the first time explored the effects of QSM on microbial composition and flavor synthesis in the Baijiu field.