Application of biosurfactant produced from peanut oil cake by Lactobacillus delbrueckii in biodegradation of crude oil

Lactobacillus delbrueckii cultured with peanut oil cake as the carbon source yielded 5.35 mg ml−1 of biosurfactant production. Five sets of microcosm biodegradation experiments were carried out with crude oil as follows: set 1 – bacterial cells + crude oil, set 2 – bacterial cells + crude oil + fertilizer, set 3 – bacterial cells + crude oil + biosurfactant, set 4 – bacterial cells + crude oil + biosurfactant + fertilizer, set 5 – with no bacterial cells, fertilizer and biosurfactant (control). Maximum degradation of crude oil was observed in set 4 (75%). Interestingly, when biosurfactant and bacterial cells were used (set 3), significant oil biodegradation activity occurred and the difference between this treatment and that in set 4 was 7% higher degradation level in microcosm experiments. It is evident from the results that biosurfactants alone is capable of promoting biodegradation to a large extent without added fertilizers.