Asian Journal of Biotechnology and Bioresource Technology

Degradation of crude oil by bacteria isolated from three plantations soil at Idanre, Nigeria were comparatively investigated. Soil samples collected by hand trowel at 5cm rhizosphere of Cocoa, Orange, and Teak plantations from Idanre, Ondo State. The crude oil – forcados blend was obtained from Warri, Delta State, Nigeria. Gram negative bacteria were isolated from rhizosphere soil sample using standard microbiological methods. Preparation of Biomass was done by centrifuging nutrient broth repeatedly to wash cells. Harvested cells were obtained for the degradation of crude oil. Harvested cells were inoculated with crude oil and then incubated in a shaker. Degradation of crude oil was monitored by using spectrophotometer to read the OD at 540 nm.  The bacteria isolated from rhizosphere of cocoa include: Citrobacter freundii, Yersinia pestis, Edwardsiella tarda,. Serratia marcescens. Rhizosphere of orange; Providencia stuatii while Enterobacter agglumerans, Moellerella wisconsis were isolated from rhizosphere of teak. The most effective hydrocarbon utilizing bacteria was Enterobacter agglumerans, which resulted in increase in population densities and reduction in hydrocarbon contents in the crude oil. Findings from this study shows the effectiveness of degrading hydrocarbon in liquid medium and further confirmed the potency of bacterial cells to degrade crude oil.