Abstract

Effluents released from petroleum refining typically contain microbes that are naturally adapted to using these hydrocarbons for their metabolic needs. In this study, the ability of Pseudomonas putida and Bacillus megaterium isolated from a petroleum refinery effluent to degrade diesel and spent engine oil was assessed; they were identified among the bacteria isolated using conventional biochemical and phenotypic tests. The strains (Pseudomonas putida C15a and Bacillus megaterium N9a) showing the highest potential were selected for the biodegradation studies; they were tested individually and in consortium for their ability to utilize the hydrocarbons by monitoring the hydrocarbon utilizing bacterial counts (HUB) and percentage hydrocarbon degradation. The consortium performed least efficiently than the individual strains; Pseudomonas putida C15a degraded 98.3% of diesel hydrocarbons with a HUB count of 1.85 x 10 7 CFU/mL. The strain of Pseudomonas putida (C15a) isolated in this study is a very good candidate for bioremediation studies of petroleum hydrocarbons.