Surfactin-Producing Bacillus velezensis A1 Inhibits Lactic Acid Bacteria in Jiang-Flavor Baijiu Fermentation

Lactic Acid Bacteria contribute to heightened acidity in the fermentation process of Jiang-flavor Baijiu due to their production of lactic acid. High-temperature Daqu may act as a reservoir for beneficial microorganisms and antimicrobial compounds. In this study, we utilized 16S rRNA and ITS amplicon sequencing to identify microbial taxa in high-temperature Daqu that inhibit the primary lactic acid bacterium involved in Jiang-flavor Baijiu fermentation, Acetilactobacillus jinshanensis, followed by the selection of antagonistic strains. The strain exhibiting the strongest antagonistic activity was identified as Bacillus velezensis based on whole-genome sequencing. Genome analysis revealed 12 secondary metabolite biosynthetic gene clusters, from which one lipopeptide was identified. This lipopeptide was demonstrated to antagonize A. jinshanensis AJS1 by disrupting the cell membrane and inducing leakage of intracellular contents. Collectively, strain A1 and its secondary metabolites exhibit considerable promise as antagonistic agents to mitigate acidity increases triggered by A. jinshanensis AJS1 during the fermentation of Jiang-flavor Baijiu.