Characterization of two biosurfactant producing strains in crude oil degradation

Abstract

Pseudomonas sp. BP10 and Rhodococcus sp. NJ2, isolated from crude oil contaminated site, were found to be potential degraders of different fractions of crude oil. Pseudomonas sp. BP10 degraded 60.6% of TPH (total petroleum hydrocarbons) while Rhodococcus sp. NJ2 metabolized only 49.5% after 30 days of incubation in MSM (minimal salt media) with 2% of crude oil at their optimum conditions. A difference in oil degradation ability of the bacteria may be linked to several inherent factors like catabolic enzymes, cell hydrophobicity, biosurfactant production, etc. A significant reduction in the surface tension as a result of higher biosurfactant production by Pseudomonas sp. BP10 might be attributed to its higher degradation ability of crude oil than Rhodococcus sp. NJ2. In both the bacteria, activity of catechol 1,2 dioxygenase was invariably higher than catechol 2,3 dioxygenase. Although both catechol dioxygenases participated in degradation of crude oil, but higher activity of catechol 1,2 dioxygenase in Pseudomonas sp. BP10 than in Rhodococcus sp. NJ2 indicates that this enzyme played a significant role in crude oil degradation. Formation of the intermediates in oil degradation process as measured in terms of resorcinol equivalent was also evidently more in Pseudomonas sp. BP10 than Rhodococcus sp. NJ2.