Bacteria from oil contaminated sites as a viable source of potential biosurfactants with anti-microbial and anti-biofilm activities

Abstract

Biosurfactants are low molecular weight, surface active amphiphatic compounds produced by microorganisms. These molecules could be of wide acceptability in cosmetic, pharmaceutical, food industries and bioremediation processes due to low toxicity and biodegradability. However, there is a limitation in their applicability partially due to our knowledge that revolves around pretty less number of well studied biosurfactants. The aim of the present study is to isolate bacteria from oil contaminated environments (soil from automobile workshops and kitchen waste dumping area), and evaluate them for biosurfactant production and determining the properties of these biomolecules. Isolates were screened for drop collapse activity, emulsification, phenol–sulfuric test and ability of adhesion to hydrocarbons. Isolates selected on the basis of above activities were screened for antimicrobial activity against Bacillus cereus, Escherichia coli, Klebsiella sp., Pseudomonas aeruginosa and Staphylococcus aureus. Biosurfactants with antimicrobial activity were also checked for ability to reduce adhesion of pathogenic microorganisms to solid surface and evaluated for biofilm-disruption activity. The results obtained in this work showed that the biosurfactant from isolate SBM1 identified as Bacillus sp. had all the above properties. Thin layer chromatography (TLC) and Fourier transform infrared spectroscopy (FTIR) analysis confirmed that biosurfactant from isolate SBM1 is of glycolipid type that can be employed as potential agent of biomedical utility.