Biodegradation of Selected Petroleum Hydrocarbons Using Indigenous Microorganisms

Bioremediation make use of microorganisms to remove contaminants from the environment, the use of indigenous microorganisms in the bioremediation of hydrocarbon pollutant to clean up environment has become a valuable technique. This study was aimed to biodegrade some petroleum hydrocarbon using indigenous microorganism from the petroleum contaminated soil. Top soil sample was collected from petroleum contaminated site in Minna, Nigeria. The petroleum was obtained from a local petrol bunk. The indigenous microorganism with biodegrading potential was obtained by plating the aliquot of the soil sample on minimal salt medium containing petroleum as the only source of carbon. The bacterium was identified by cultural and biochemical test and the fungi were identified by both macroscopic and microscopic examinations. The isolates with optimal potential were then subjected to biodegradation for 25 days. A control was setup without the isolate. Three bacterial isolate and four fungi isolate were isolated from the petroleum contaminated site, the bacterial isolates were Corynebacterium xerosis with maximal rate of degradation on day 20 (86%), the control had 12%, Proteus vulgaris maximal rate of biodegradation was on day 35 (80%) while that of control is 40%, and Bacillus subtilis maximal rate of biodegradation was on day 10 (49.73%) while that of control is 2.2%. The fungi isolates were identified as Aspergillus niger, A. versicolar , Trichophyton verrucosum Bodin and Saccharomyces cerivisiae . Trichophyton verrucosum Bodin on day 25 had the highest percentage (88%) of biodegradation in comparison with the control 41%. While A. niger highest biodegradation was observed on day 15 (24%). There was a gradual increase in the count of all the isolate during the course of biodegradation. The result of this study showed that these isolates were able to degrade petroleum hydrocarbon and can be useful for large scale bioremediation of petroleum contaminated soils.