Petroleum Degrading Potentials of Bacterial Isolates from River Ethiope, Delta State, Nigeria

Abstract

Water samples were collected from twelve locations along the Ethiope River, Delta State, Nigeria to determine the petroleum degrading potentials of bacterial isolates and their x-ray mutants using standard methods. Bacteria isolated were Bacillus sp, Klesiella sp, Escherichia sp, Micrococcus sp, Pseudomonas sp, Staphylococcus sp and Streptococcus sp. All the isolates and their x-ray mutants possessed ability to degrade 1% (v/v) Forcados crude-oil with Bacillus sp, Escherichia sp and Pseudomonas sp isolated from a location, with reported crude-oil spillage, degrading 2.5% (v/v). X-ray mutation led to % kill that ranged from 3.58 (Micrococcus sp) to 11.59 (Streptococcus sp). There were reduction in crude-oil degradation in mutants from 0.33% (Escherichia sp) to 6.31% (Pseudomonas sp) with parent Pseudomonas sp (1.680 ppm) and mutant Streptococcus sp (1.474 ppm) being highest and least degraders respectively. Statistically significant differences (t= 0.95) in crude-oil degradation were observed for parents and mutants of Streptococcus sp, Escherichia sp and klebsiella sp but not for Bacillus sp, Staphylococcus sp, Pseudomonas sp and Micrococcus sp. Thus, irrespective of source of isolation on the Ethiope River, crude-oil degrading bacteria abound with increased ability on exposure to crude-oil pollution and reduced ability on x-ray mutation. The bacteria encountered in this study could be employed in bioremediation of crude-oil polluted environments.