Optimization of indigenous hydrocarbon Degrading-microbial niche for effective bioremediation of petroleum contaminated soil

Mishandling of petroleum products has been a significant source of environmental pollution and health hazards. Many microorganisms have the ability to utilize hydrocarbons as the sole source of carbon and these microorganisms are widely distributed in nature. Five (5) sites in Keffi, Nigeria were sampled to isolate hydrocarbon utilizing bacteria and fungi. The hydrocarbon products utilized were petrol, gear oil and engine oil. The hydrocarbon utilization was determined using the spectrophotometric method. A total of two (2) bacteria and two (2) fungi species were identified as the highest utilizers of the hydrocarbon products. The hydrocarbon utilization rate at the best temperature (37OC), pH (7) and time (28 days) was assessed. The utilization (mg/ml) of Pseudomonas aeruginosa for petrol ranges from 1.97±0.05, 1.31±0.034 for gear oil and 1.52±0.035 for engine oil. Alcaligenes faecalis utilization ranges from 2.2±0.022 for petrol, 1.57±0.031, for gear oil and 1.86± 0.034 for engine oil. Trichoderma harzianum ranges from 1.98 ±0.012 for petrol, 1.23±0.003 for gear oil and 1.73±0.008 for engine oil. Purpureocillium lilacinum ranges from 1.98±0.03 for petrol, 0.92±0.006 for gear oil and 1.39±0.035 for engine oil. The effect of microbial consortium on hydrocarbon utilization (mg/ml) for Pseudomonas aeruginosa and Alcaligenes faecalis ranges from 1.83 ±0.035 for petrol, 1.33 ± 0.023 for gear oil and 1.46 ± 0.015 for engine oil. Trichoderma harzianum and Purpureocillium lilacinum range from 1.88 ± 0.041 for petrol, 1.45 ± 0.026 for gear oil and 1.63 ± 0.011 for engine oil. While a microbial consortium of Pseudomonas aeruginosa, Alcaligenes faecalis, Trichoderma harzianum and Purpureocillium lilacinum ranges from 2.09 ± 0.002 for Petrol, 1.85 ± 0.031 for gear oil and 1.97 ± 0.034 for engine oil. P.aeruginosa, A. faecalis, T. harzianum and P. lilacinum constitute an effective microbial consortium for the bioremediation of hydrocarbon polluted soil.