Metabolites and Whole-Genome Analysis of the Lichenysin-Producing Bacillus licheniformis YC7

Lichenysin is a high-performance, environmentally friendly biosurfactant that also has antibacterial activity and flavor-regulating functions. During the solid-state fermentation of Baijiu, lichenysin plays key roles in inhibiting unwanted microbes and stabilizing quality. This study aims to explore the metabolic mechanisms and application potential of lichenysin-producing bacteria. High surfactant-producing strain Bacillus licheniformis YC7 was selected through the oil spreading assay, and tandem mass spectrometry (MS/MS) confirmed that its fermentation broth contains multiple lichenysin homologs. Gas chromatography-mass spectrometry (GC-MS) analysis showed that strain YC7 can produce 35 volatile flavor compounds, with pyrazine compounds being the main components. Whole-genome sequencing revealed that the genome size of YC7 was 4.31 Mb, containing 4590 protein-coding genes. A total of 10 secondary metabolite synthesis gene clusters were predicted, among which the complete lichenysin synthesis gene cluster was included. Gene annotation and functional analysis identified key genes and metabolic pathways related to the synthesis of pyrazine, acetoin, and 2,3-butanediol, indicating a high correlation between the genome and metabolome of strain YC7. In summary, this study revealed that strain YC7 had the dual potential to produce both biosurfactants and flavor compounds, providing a theoretical basis for its targeted applications.