INVESTIGATION OF HYDROCARBON BIO-REMOVAL BY THE INDIGENOUS BACTERIA ISOLATED FROM CRUDE OIL CONTAMINATED SOILS

The current study reports hydrocarbon degrading capacity of two bacterial strains isolated from soils contaminated by crude oil. Two indigenous bacterial strains (Bs1 and Bs2) were isolated from polluted soils around oil reservoirs, Ahvaz, Iran. Their abilities to degrade different hydrocarbons, including olive oil, crude oil and coal tar were investigated, using measuring total organic carbon (TOC) supplemented as sole carbon source in the mineral medium. To identify bacterial isolates, morphology and biochemical characteristics along with 16S rDNA analysis were considered. The results showed strain Bs1 was able to consume more than 34 % of coal tar, 61% of crude oil, and 81% of olive oil during 14 days incubation. The hydrocarbon degrading ability of Bs2 was 24, 39, and 68% in the presence of coal tar, crude oil and olive oil, respectively as sole carbon source. Additionally, their mixed culture of two isolates led to a 5% increase in their biodegradation effectiveness. The subsequent morphological and biochemical characterization and phylogenetic analyses showed the close relationship of Bs1 and Bs2 (about 98 and 99%) to Pseudomonas aeruginosa strains of CMG581 and BM8, respectively.