Production of biosurfactant from a new and promising strain of Leucobacter komagatae 183

The Leucobacter komagatae 183 strain, isolated from mangrove sediment in Trang, southern Thailand, was evaluated as a potential biosurfactant producer. The biosurfactant production was carried out by using a mineral salt medium with commercial sugar and monosodium glutamate as the carbon and nitrogen source, respectively. The microbial growth was investigated and the best cultivation time for the biosurfactant was found to be 54 h. After the microbial cultivation at 30°C under optimized conditions, the biosurfactant produced was found to reduce the surface tension of pure water to 26.5 mN/m with the critical micelle concentration of about 9 mg/l. The stability of the biosurfactant at different salinities, pH and temperature and also its emulsifying activity has been investigated. It is an effective surfactant at very low concentrations over a wide range of temperatures, pHs and salt concentrations. The crude biosurfactant showed a broad spectrum of antimicrobial activity and also had the ability to emulsify oil and enhance PAHs solubility.