Screening and Characterisation of Biosurfactant Producing Lactic Acid Bacteria

Biosurfactant is a surface active compound having amphiphilic nature that reduce surface tension and interfacial tension between two insoluble phases. This study is intended to isolate lactic acid bacteria (LAB) and their capabilities to produce biosurfactants. LAB is widely found in milk and milk products, oil contaminated soil, and fruits etc. , and produce biosurfactant during their late exponential and stationary phase of growth. Total 10 samples were collected from various milk and milk products and studied for lactic acid bacteria for production of biosurfactant. LAB are isolated using sterile MRS agar supplemented with 1 % calcium carbonate. Oxidase and catalase negative isolates showing hemolytic activity are screened for biosurfactant production. Modified MRS broth without tween 80 is used for the production of biosurfactant, under static Condition up to 72 hours and centrifuged the broth for obtaining cell free supernatant (CFS) and checked it for biosurfactant production by oil spreading method. Among 10 samples collected, 18 isolates were identified as lactic acid bacteria.10 isolates among were screened and further tested for biosurfactant activity. Anti-adhesive activity of biosurfactant producing LAB was checked against Pseudomonas aeruginosa, Staphylococcus aureus. Thin layer chromatography was carried out to characterized the biosurfactant produced by LAB.