Boosting baijiu fermentation efficiency through designed microbial community coalescence: Enhanced substrate conversion and flavor output.

In this study, we designed a synthetic community (SynCom) for directedly monitoring the yield of phenolic compounds and other flavor compounds of Baijiu, through inoculating the coalescence of synthetic community and autochthonous starter culture (Daqu). Compared with the fermentation endpoint, this SynCom, comprised of Wickerhamomyces anomalus, Pantoea agglomerans and Bacillus altitudinis, significantly enhanced the substrate utilization and metabolites formation.Specifically, the consumption of starch and protein was increased by 42.68% and 24.37%, respectively, calculated as the relative increase in consumption from the initial to the endpoint in the model group over that in the control group. Meanwhile, the yield of targeted aromatic compounds increased by 25.9%, with 4-methylguaiacol exhibiting a particularly marked increase from trace levels. Furthermore, we deduced W. anomalus exerted a strong priority effect to constitute over 90% niche of the fungal community and reduce 25% diversity of the community in the front fermentation stage. Therefore, the priority species provided a competitive starving and metabolism of the upcoming species (P. agglomerans and B. altitudinis), and their synergism contributed to the enhancement of targeted phenolic compounds and specific esters in the later stage of fermentation. Our study provided insight into monitoring and controlling the formation of desired compounds through the coalescence of a designed community and a common starter culture. This study also provided a validated framework for the rational designed consortia to control and improve the quality and function of complex fermented foods.