Abstract

The ability of four bacterial species (Pseudomonas sp., Bacillus sp., Klebsiella sp. and Proteus sp.) to utilize some petroleum hydrocarbons (kerosene, engine oil and automotive oil) was studied. Laboratory experiments were conducted over a five day period in Erlenmeyer flasks containing mineral salt medium (MSM) under aerobic conditions using the hydrocarbons as carbon sources. A bacteria consortium capable of utilizing the hydrocarbons was prepared from the bacterial cultures. All the bacterial species utilized the hydrocarbons as sole carbon and energy sources showing increases in cell number and optical density with decreases in pH of the culture media, and carbon dioxide (CO₂) evolution. Data from statistical analyses showed significant difference (p<0.05) in the utilization competence of the bacterial cultures on the three hydrocarbon substrates. A significant variation was observed between the efficiency of single and mixed bacteria cultures. Mixed bacterial cultures showed the most appreciable growth on the substrates tested. It was also observed thatPseudomonas sp. utilized the three hydrocarbons better than the other bacterial species. This study has shown that the mixed bacterial cultures have potential application in the bioremediation of sites polluted with kerosene, engine oil and automotive oil and can assist researchers in developing strategies for removing hydrocarbon pollutants from the environment.

Key words: Biodegradation, bioremediation, mixed bacterial cultures, hydrocarbons, bacterial consortium.