Abstract

High on the table of environmental discussions worldwide today is the problems of petroleum hydrocarbon contamination. This research focused on screening for the potentials of five bacterial isolates in utilizing the following hydrocarbon substrates [gasoline, diesel and kerosene (2.0v/v) in Bergs Mineral Salt Medium (BMSM)]. The effects of different nutrients supplementation on biodegradation indices were assessed. The biodegradation indices that were monitored included optical density (OD _{600 mn}), emulsi-fication stability (E₂₄) and gas chromatography (GC) profiles. The results from the GC profiles show that all the isolates had well above 80% reduction in the hydrocarbon substrates. Enterobacter cloacae showed the greatest potential with respect to gasoline degradation efficiency under soy supplement (99.66%). For diesel degradation, Pseudomonas cepacia and the consortium were at par with respect to the degradative efficiency, that is, 99.80%. For kerosene degradation studies, E. cloacae gave the highest degradation efficiency of 95.60%. As compared to the controls, these degradation efficiencies were relatively high. The above results purports that the all the strains especially Enterobacter cloacae and consortium are possible candidates for ameliorating the problem of hydrocarbon contamination.

Key words: Bacteria, hydrocarbons, biodegradation, gas chromatography.