Isolation of Oil – Degrading Microorganisms in Spent Engine Oil – Contaminated Soil

Abstract

The isolation and characterisation of oil-degrading microorganisms in spent engine oil-contaminated soil were carried out. The density of heterotrophs ranged from 0.2 × 10⁴ cfu/g to 62.5 × 10⁶ cfu/g for bacteria and 1.5 × 10³ cfu/g to 1.5 × 10⁵ cfu/g for fungi. The density of oil-degraders in the soil samples ranged from 0.03 × 10³ cfu/g to 5.0 × 10³ cfu/g for bacteria and 1.0 × 10² cfu/g to 3.0 × 10³ cfu/g for fungal isolates. Micrococcus species were the best bacterial oil-degraders while Aspergillus and Penicillium species degraded the greatest amount of oil among the fungi. Micrococcus and Pseudomonas species were the most predominant organisms in the soil while Klebsiella and Bacillus species occurred less frequently. The concentration of oil correlated with the density of microorganisms in the soil sample.

Keywords: Oil Degradation, Bacteria, Fungi.