Isolation and Characterization of Bacteria with Potential as Hydrocarbon Component Degraders from Bitumen-contaminated Soil

Abstract

Petroleum hydrocarbons are considered the main energy source and provide raw materials for many industries. There are always environmental problems in places where exploration activities take place, due majorly to spillage. Hydrocarbon contamination poses a significant ecological and health threat in the environment. In this work, bacterial isolates capable of degrading crude oil were isolated from bitumen contaminated soil in Agbabu community Ondo State. Isolation of the hydrocarbon degrading bacteria was carried out on modified minimal salt medium (MSM), with crude oil as the sole carbon source. Isolated bacteria were characterized by biochemical and molecular methods. Biodegradation experiment was carried out using different concentrations of crude oil (10%, 20%, and 30%) in broth. Residual oil was analyzed using gravimetric method and gas chromatography mass spectrometry (GC-MS). Thirty-three (33) bacteria with the ability to use bitumen as sole carbon source were isolated. The six best hydrocarbon degrading bacteria were characterized by 16SrRNA, as Rossellomorea aquimaris, Stutzerimonas stutzeri, Pseudomonas sp1, Pseudomonas sp2, Pseudomonas cironellolis and Kocuria indica. The crude oil degrading ability of the six bacterial characterized showed that the highest degrading activity was observed in Rossellomorea aquimaris at 99%, for 10% concentration of crude oil, while the lowest degrading activity was observed in Kocuria indica at 6% for 30% of crude oil. The chromatograph spectra of the crude oil supplemented broth of the bacteria isolates showed different fractions from C10 to C40 interspersed with Pristane and Phytane at different quantities degraded. In conclusion, the six bacteria isolates have the ability to biodegrade crude oil at different concentrations.  These bacteria could be of huge benefits for land reclamation.