Isolation of Biosurfactant-Producing Bacteria : Effect of Carbon Source and Activity of Oil Recovery
Biosurfactant are gaining more and more attention and have already been taken for a number of important industrial uses, due to their several advantages of biodegradability, capability to produce from renewable resources, good functionality under extreme conditions; particularly those pertaining during tertiary crude-oil recovery, and good compatibity to human beings. The biosurfactant solution produced from Bacillus Subtilis PT2, isolated from an oil sludge was studied its properties. The surface tension of nutrient broth was reduced to 26.4 mN/m when PT2 was incubated with 2% palm oil at 37 °C, 51 hours, as compared to an incubation time of 36 hours with sludge oil, suggesting that PT2 is compatible with sludge oil more than palm oil. The critical micelle concentration (CMC) of the produced biosurfactants, after cultivation for 51 hours, was found to be 250 mg/l, corresponding to a minimum surface tension of 26.4 mN/m. From the oil recovery results, the oil recovery efficiency of the produced biosurfactants was 61.6 and 57.1 % for motor oil and palm oil, respectively.