Application of a Biosurfactant from Bacillus velezensis GJ1 as an Emulsifier and Antibacterial Agent for Food Systems

초록

The demand for natural and multifunctional ingredients in food systems has increased interest in microbial biosurfactants as potential alternatives to synthetic emulsifiers and antimicrobial agents. However, their practical functionality in food systems remains insufficiently explored. Here, a biosurfactant produced by Bacillus velezensis GJ1 was evaluated as a functional emulsifier and antibacterial agent for food applications. Wholegenome sequencing confirmed the presence of lipopeptide biosynthetic gene clusters associated with surfactin and iturin production, while no genes related to known virulence factors were detected, supporting the safety of the strain. The emulsifying performance of the biosurfactant was assessed using various food-grade oils and compared with commercial surfactants. The biosurfactant formed stable emulsions with canola, corn, grapeseed, olive, soybean, and sunflower oils, exhibiting emulsification indices comparable to those of Tween 80 and Span 80. Microstructural analysis further revealed that emulsions stabilized with the biosurfactant displayed droplet characteristics similar to those formed with Tween 80. In addition to its emulsifying functionality, the biosurfactant exhibited antibacterial activity against Escherichia coli, with minimum inhibitory and bactericidal concentrations of 256 and 512 mu g/mL, respectively, comparable to those of the food-grade antimicrobial nisin. Application in a sausage-based food model resulted in a significant reduction of E. coli populations, achieving a maximum decrease of approximately 2.8 log CFU/g and exceeding the antibacterial effect of nisin under the same conditions. These findings demonstrate that the biosurfactant produced by B. velezensis GJ1 exhibits both emulsifying and antibacterial functionalities, highlighting its potential as a natural multifunctional ingredient for food systems.

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