There is much concern about the effect of oil pollution in the environment which has led to a global interest in the microbial biodegradation of pollutants in the recent years. In order to reduce or eliminate the effect of oil spillage on the environment and living organisms using biological process, a study was carried out to isolate oil-degrading bacteria associated with oil-polluted lands in River State, Nigeria. Crude oil was supplied to the enrichment culture as a sole carbon and energy source. The degradative ability of the isolates was determined by optical density. A total of 10 oil-degrading bacterial strains were isolated from soil and water samples polluted with oil in River state. All isolates were characterized by molecular method. Phylogenetic analyses of 16S rRNA gene sequences were examined in order to determine the evolutionary relationships of the isolates. Six species belong to the gamma subdivisions of Proteobacter, one specie belong to the division Firmicutes (Gram +ve bacteria) while three species could not be assigned to any known phylum. The 16S rRNA analysis revealed that the isolates belonged to the genera Citrobacter, Enterobacter, Klebsiella, Aeromonas, Ewingella and Pseudomonas. The percentages of Proteobacteria and Firmicutes in soil were greater than those in the water samples. The application of molecular methods for rapid detection of diverse strains of oil-degrading bacteria for bioremediation process is of great relevance in promoting a sustainable development of our environment with low environmental impact.
