Whole genome sequencing analysis of a novel exopolysaccharide-producing Bacillus velezensis and its impact on the quality of soy sauce

This study aimed to develop a novel exopolysaccharides (EPS)-producing strain, Bacillus velezensis KUST4317 (BVK), isolated from soy sauce as a multifunctional starter culture for fermented foods. The evaluation mainly focused on its biosafety, metabolic potential, and functional characteristics. Genomic analysis confirmed the strain's biosafety, identifying only seven non-critical antibiotic resistance genes and no virulence factors. BVK exhibited a high EPS yield (250 mg/L), which contributed to increased soy sauce viscosity (1-1.2 mPa·s) and exhibited strong antioxidant activity (76.4 % DPPH scavenging). Metabolomic profiling revealed that BVK uniquely produces flavor-enhancing compounds (e.g., benzyl alcohol, pyrazines), while preserving essential taste components. Further mechanistic analysis identified ATP-Binding Cassette (ABC) transporters as key pathway involved in EPS biosynthesis. These findings highlight the potential of BVK to enhance both the functional and sensory qualities of fermented foods.