Microbiological and physiochemical analyses of oil contaminated soil from major auto mechanic workshops in Ado-Ekiti metropolis

The ability of microorganisms to utilize used oil in contaminated soil from some selected major mechanic workshops in Ado Ekiti metropolis as a sole source of carbon and energy was studied. Soil samples collected from the two major mechanic workshops at Adebayo, and Irona Quarters in Ado-Ekiti were analyzed for the microbiological and physicochemical qualities using the basic microbiological methods. The physicochemical properties of the soil samples shows that the value of pH range from 5.45 to pH 5.58, percentage of carbon range from 3.98 % to 4.20%, nitrogen content varies from 2.20 to 2.40. The total heterotrophic bacterial counts from the mechanic workshops ranges from 7.52 x 106 to 8.25 x 106cfu/g while the total heterotrophic fungal counts ranges from 5.54 x 106 to 6.25 x 106 cfu/g. The bacterial recovered from the oil contaminated soils include Staphylococcus spp., Pseudomonas aeruginosa, Bacillus spp., E. coli and Acinobacter spp. The frequency of occurrence of the microbial isolates revealed that Bacillus cereus 5 (31.25%) occurred most, followed by Pseudomonas aeruginosa (18.75%), Acinetobacter spp. (18.75%) and E. coli (18.75%) while Citrobacter freundii (12.50%) had the lowest frequency of occurrence. The results of this study have showed that some of the isolated organism can be used for bioremediation of the contaminated soil.