Production and characterization of biosurfactants produced by microorganisms isolated from milk factory wastewaters

Abstract

Biosurfactants or surface‐active compounds are produced by microorganisms. These molecules reduce the surface tension of both aqueous solutions and hydrocarbon mixtures. In this study, the isolation and identification of biosurfactant‐producing microorganisms were assessed. The characterization of biosurfactant produced by microorganisms isolated from milk factory wastewaters was investigated. For this purpose, five different microorganisms were isolated and identified. In order to determine the biosurfactant production, the ‘drop‐collapse’ method was applied and it was determined that only three species, Yarrowia lipolytica MFW5 (yeast), Micrococcus luteus MFW1 (cocci) and Burkholderia cepacia MFW2 (bacillus), were able to produce biosurfactant. Biosurfactants produced by Yarrowia lipolytica, Micrococcus luteus and Burkholderia cepacia were coded as BS‐I, BS‐II and BS‐III, respectively. After the initial biosurfactant production and characterization studies were completed, isolates of these three species were incubated with whey wastewaters at 35°C for 10 days for biosurfactant production. At the end of the incubation period, the biosurfactants were extracted and further characterized with biochemical analysis, FTIR spectra, haemolysis test, emulsification test and determination of the surface tension.

Keywords:

• biosurfactant‐producing microorganisms
• whey
• haemolysis
• emulsification

Acknowledgements

This work was financially supported by the Kirikkale University Research Fund with grant number 2007/47.