Indigenous Bacteria and Fungi Responsible For Bioremediation of Oil-Polluted Soils in Ondo State, Nigeria
*1Olukunle, O. F., 2Boboye, B. and 3Ikuomola, O.T.
Department of Microbiology, Federal University of Technology, P. M. B 704, Akure, Ondo State, Nigeria.
*Corresponding Author:email: firstname.lastname@example.org, Tel. No.: +2348036141743
Accepted on June 8, 2012
In order to reduce or eliminate the effect of oil spillage on the environment and living organisms using biological process, a study was carried out to isolate oil-degrading bacteria and fungi associated with oil-polluted lands in Ondo State, Nigeria. In this study, the indigenous bacteria and fungi, isolated from some oil-polluted sites in Ondo State, Nigeria and which were able to degrade oil were investigated by the use of classical selective enrichment technique. These organisms were further studied to determine their biodegrading activities on hydrocarbons containing 2% (v/v) (diesel, kerosene, petrol) using enrichment medium. The microbial growths were determined using spectrophotometer. The physicochemical properties of the environmental samples were analysed using standard procedures and compared with the unpolluted samples.The bacterial isolates were identified by morphological and biochemical characterization using the taxanomic scheme of Bergey’s Manual of Determinative Bacteriology. The bacteria obtained from the oil-polluted sites were Bacillus firmus, Bacillus sphaericus, Staphylococcus aureus, Microcococcus sp., Acinetobacter sp., Pseudomonas sutzeri and Bacillus pumilus. Fungi isolated from the various sites included Penicillium italicum, Aspergillus niger, Penicillium oxalicum, and Streptothrix atra, based on the microscopic and macroscopic features of the hyphal mass, nature of the fruiting bodies and the morphology of cells and spores. These results showed that all the microbes maximally utilized the oil substrates (petrol, diesel, and kerosene) when supplied as the sole source of carbon and energy. The test on the degrading activity of isolates on oils revealed that B firmus, and Penicillium oxalicum are best degraders of petrol while B. sphaericus and Aspergillus niger and B. sphaericus and Streptothrix atraare bestdegraders of diesel and kerosene respectively. The physicochemical properties of the polluted soils showed higher levels of Pb. Zn and Fe than the unpolluted soil samples. The pH values obtained in this study were not too low or high which supported biodegradation activity of bacteria and fungi in the soil. The bacteria and fungi obtained in the study areas coupled with the pH value, revealed microbial activities during degradation, although at very slow rate. Further research into enhancing the degradation process by altering environmental factors and manipulating the genetic make up of these bacteria and fungi for effective and efficient bioremediation process will be of great relevance in promoting a sustainable development of our environment.