Utilization of palm oil decanter cake as a novel substrate for biosurfactant production from a new and promising strain of Ochrobactrum anthropi 2/3

Abstract

A biosurfactant-producing bacterium, isolate 2/3, was isolated from mangrove sediment in the south of Thailand. It was evaluated as a potential biosurfactant producer. The highest biosurfactant production (4.52g/l) was obtained when the cells were grown on a minimal salt medium containing 25% (v/v) palm oil decanter cake and 1% (w/v) commercial monosodium glutamate as carbon and nitrogen sources, respectively. After microbial cultivation at 30°C in an optimized medium for 96h, the biosurfactant produced was found to reduce the surface tension of pure water to 25.0mN/m with critical micelle concentrations of 8.0mg/l. The stability of the biosurfactant at different salinities, pH and temperature and also its emulsifying activity was investigated. It is an effective surfactant at very low concentrations over a wide range of temperatures, pH and salt concentrations. The biosurfactant obtained was confirmed as a glycolipid type biosurfactant by using a biochemical test, fourier-transform infrared spectroscopy, MNR and mass spectrometry. The crude biosurfactant showed a broad spectrum of antimicrobial activity and also had the ability to emulsify oil and enhance polyaromatic hydrocarbons solubility.