Isolation and characterisation of biosurfactant-producing bacteria from oil contaminated sources

Abstract

The mam objective of this study was to test a range of micro-organisms for biosurfactant production, with the potential usage of these surfactants in bioremediation. Fourteen isolates were screened for their ability to produce biosurfactants when grown in a minimal salt medium containing cooking oil as sole carbon source. The organisms with the highest emulsification activities were further tested for their ability to utilise different carbon sources for faster biosurfactant production. The results show that B. subtilis, B. cereus and M luteus show optimum emulsification activity in oil after six days, but have the ability to produce biosurfactants on ethanol or glucose after forty-eight hours. Protein, carbohydrate and lipid assays were also performed on the isolated biosurfactants and these results indicate that various types of biosurfactants are produced during the growth of these organisms on the different hydrocarbons. Lastly surface tension measurements were performed on the isolated surfactants, as well as those present in the culture broths. The results of this study show that biosurfactant-producing micro-organisms can successfully be isolated from oil polluted environments.