Asian Journal of Microbiology and Biotechnology

The disposal of spent oil into open vacant plots and farms, gutters and water drains is an environmental risk. This study was conducted to explore the bioremediation of spent engine oil polluted soil enhanced with blends of poultry manure and pig dung, as well as its effects on microbiological composition of the soil. Top soil (0-15 cm depth) samples were collected from areas with history of spent engine oil contamination within Anyigba, Kogi State, Nigeria. One kilogram of soil was measured into nine clean dry containers of three litres each. The prepared blends of poultry manure and pig dung (PMPD) was mixed with the soil samples at the rate of 0, 50 and 100 g kg^-1 soil in triplicates. The experiment used a Completely Randomized Design. Soil samples were taken from each container at 0 and 28 days for hydrocarbon utilizing bacteria and total petroleum hydrocarbon determination using standard methods. Data obtained from the experiment were subjected to descriptive and inferential statistics. The species identified were Enterobacter sp and Pseudomonas aeuginosa. Enterobacter sp was the most predominant isolate. The total petroleum hydrocarbon (mgkg^-1) of the soil on day 0 was 59.78±1.84. After the amendments (at control, 50 and 100 g kg-¹), the total petroleum hydrocarbon (mgkg^-1) values were 44.92 ±2.26, 35.54 ± 2.78 and 29.52±1.28 at 28 days respectively. The blends of PMPD and the high level carbon utilizing bacteria, Enterobacter sp, showed promising potentials in the bioremediation of spent engine oil polluted soil by significantly enhancing the biodegradation process, as an impressive 50.62% remediation efficiency was achieved 28 days after amendment in soil treated with 100g of PMPD blend.