Biodegradation Potentials of Bacterial Isolates from Auto-Mechanic Workshops in Oluku, Edo State, Nigeria

Abstract

The frequent discharge of used petroleum products from automobiles has become a major source of concern due to unguided discharge into the soil environment, hence the need for biodegradation of the products. Bacterial species were isolated from contaminated soil in mechanic workshops and screened for their for hydrocarbon degradation potentials using standard microbiological procedures. Physicochemical properties of the contaminated soil were also analysed using standard techniques. The highest and lowest heterotrophic bacterial counts of 2.82 ± 0.16 ×108 and 2.09 ± 0.32 ×108 cfu/g were from the control soil and site 1 respectively. For hydrocarbon utilizing bacterial, Site 2 had the highest load of 8.33 ± 2.55 ×105 while the control had the least 1.35±0.33× 104 cfu/g. The bacterial isolates from the contaminated soil were found to be Corynebacterium kutsceri, Escherichia coli, Bacillus licheniformis, Bacillus subtilis, Bacillus megaterium, Klebsiella oxytoca, Staphylococcus aureus, Pseudomonas aeruginosa and Micrococcus luteus. The highest and lowest in the frequency of occurrence among the isolates were B. subtilis (27.5 %) and E. coli (1.4%) respectively. The screened hydrocarbon utilizing bacterial isolates were C. kutseri, B. subtilis and P. aeruginosa. The ability to degrade crude oil revealed that bacterial consortium had the highest growth profile of 12.90 ×105 while the least was C. kutsceri with values of 8.20 ×105 cfu/g. The consortium bacteria had the highest percentage of hydrocarbon products degradation. The ability of the consortium bacteria to remove a high percentage of crude oil components makes it potentially useful for bioremediation of site highly contaminated with petroleum hydrocarbon.