Antimicrobial and anti-adhesive activities of cell-bound biosurfactant from Lactobacillus agilis CCUG31450

Abstract

In this work, biosurfactant production by different Lactobacillus strains was studied using the conventional MRS medium for lactic acid bacteria. Lactobacillus agilis CCUG31450 produced a cell-bound biosurfactant that reduced the surface tension of water to 42.5 mN m⁻¹, and exhibited a high emulsifying activity (E₂₄ = 60%). The amount of biosurfactant produced was 84 mg l⁻¹, with a cmc of 7.5 mg ml⁻¹. A preliminary chemical characterization by Fourier transform infrared spectroscopy indicated that the biosurfactant is a glycoprotein. Using cheese whey as an alternative culture medium, biosurfactant production was increased up to 960 mg l⁻¹. The biosurfactant exhibited a considerable anti-adhesive activity against Staphylococcus aureus, as well as antimicrobial activity against S. aureus, Streptococcus agalactiae and Pseudomonas aeruginosa. This study represents the first description of a biosurfactant produced by a L. agilis strain. The results obtained open future prospects for the application of this biosurfactant to reduce or inhibit the adhesion of pathogenic microorganisms (such as S. aureus) in several biomedical applications.