Microbial Remediation of Used Engine Oil from Contaminated Soil around Automobile Workshop in Calabar Metropolis, Cross River State, Nigeria

Microbial biodegradation of engine oil contaminated soil in Calabar Metropolis was studied for a period of six (6) months (January to June, 2017). The soil samples collected were ice boxed and taken to the laboratory for microbial, total hydrocarbon, total organic carbon and other physico-chemical parameters analysis. A total of thirteen (13) indigenous bacteria species were identified in the soil of the sites analyzed during the study, which includes; Staphylococcus spp., Pseudomonas aeruginosa, Bacillus spp., E. coli, Enterococcus feacalis, Shigella spp., Arthrobacter spp., Alcaligen spp., Acinobacter spp., Azotobacter spp., Aeromonas spp., Xanthomonas spp. and Clostridium spp. The most abundant bacteria in the contaminated site was Staphylococcus spp. (65%) while the least bacteria count in the contaminated site was Clostridium spp. (9%). Staphylococcus spp. was the most abundant indigenous bacterial species and also the most effective biodegradation bacteria. The identified indigenous bacteria utilized the hydrocarbons, multiplied rapidly and then degraded the total hydrocarbon and total organic carbon more in the contaminated site compared to the control site. Site one recorded the highest bacteria count (927) while the least bacteria counts were recorded in the control site (81). The bacteria species showed its degradation and bioremediation capabilities prompting the need for its use in cleaning crude oil contaminated sites, due to the fact that it is cheap and not environmentally harmful.