Evaluation of Crude Oil Biodegradation Potentials of Some Indigenous Soil Microorganisms

Abstract

This study evaluated the crude oil degradation potentials of some indigenous soil microorganisms. The microbial isolates were among those obtained from crude oil contaminated and uncontaminated agricultural soils of Awoye, Orioke-Iwamimo, Igodan-Lisa and Oba-Ile all in Ondo State, Nigeria. The isolates were tested for crude oil degradation potentials by visual turbidity, extent of breakdown of overlaid oil and the optical density by spectrophotometry method at the wavelength of 540 nm. Brevundimonas diminuta, Bacillus subtilis, Flavobacterium species, Enterobacter species, Klebsiella pneumoniae, Pseudomonas aeruginosa, Alcaligenes faecalis, Bacillus megaterium, Klebsiella edwardsii, Bacillus aryabhattai, Aspergillus flavus, Kodamaea ohmeri, Cephalosporium species, Mucor mucedo, Paecilomyces variotii, Candida parapsilopsis and Trichoderma species were among the sixteen bacterial and seven fungal isolates tested. The findings in this study revealed varying optical densities of 0.324-0.647 for bacteria and 0.497 -0.812 for fungi at days 11 and 17 respectively thus suggesting different responses and potentials to breakdown crude oil. The highest degradative ability was shown by Klebsiella edwardsii (OD 0.647) followed by Pseudomonas aeruginosa (OD 0.575) and Klebsiella pneumoniae (OD 0.490). Paecilomyces variotii showed the highest degradative ability (OD 0.812) among the fungi. The results also suggest that these microorganisms with high degradative ability may be useful in seeding petroleum hydrocarbon polluted agricultural soils for bioremediation.