Study of biodegradation ability of some petroleum derivatives by native bacteria isolated from plants rhizosphere

Some bacteria present a capability in bioremediation of oil derivatives. In this study the bacteria existing in the plant rhizospere of polluted soils were isolated and purified. These bacteria were then exposed to a combination of commonly used petroleum products with different concentration. The bacteria that capable of biodegrading these compounds, were selected and determined using taxonomical keys and biochemical tests. Their efficiencies in removing the petroleum derivatives were compared. Finally, bacteria with the highest capability for degradation of all oil products were introduced. According to our results, Alcaligenese utrupha, Pseudomonas alcaligenes and Pseudomonas aeroginosa were isolated from rhizosphere of the soils contaminated by kerosene and gasoil; Pseudomonas alcaligenes, Bacillus coagulans, and Bacillus circulans were isolated from soils contaminated by kerosene and engine oil; and Pseudomonas alcaligenes was isolated from soils contaminated by gasoil and engine oil. Pseudomonas alcaligenes was able to biodegrade the all types of the studied oil products. The bioremediation efficiencies of this bactrium were 72, 63 and 56% repectively.