Biodegradation process of crude oil and bioemulsifier activity by a bacterial consortium culture

This study reports the analysis of biosurfactant production by a bacterial consortium
culture (CC) during biodegradation of crude oil. The ability of CC (5% v/v), grown in
Minimal Medium (MM) added with 1% (v/v) Tapis crude oil, to produce biosurfactant under
different incubation times (0, 2, 4, 6 and 8 week) was investigated. Biosurfactant activity was
estimated by water surface tension changes and emulsification index (E24). Maximum
biosurfactant production was observed at 2 weeks incubation period, after which the yield
gradually decreased. The biosurfactant produced by the CC significantly decreased the surface
tension of water from 72 dynes/cm to 52 dynes/cm (p  0.05) at week 4. Emulsification test
indicated that this biosurfactant effectively emulsified the crude oil with an emulsification
index (E24) of 85% (p  0.05). This is significantly better (p  0.05) when compared to other
chemical surfactants tested namely SDS (53.3%), Tween-20 (50.8%) and Triton X-100 (55%).
These results indicate the capability of CC to produce biosurfactant during crude oil
degradation and this can be exploited for enhanced bioremediation in oil contaminated areas