Isolation and characterization of carbonoclastic bacteria diversity in oil-contaminated soil in Cape Coast Metropolis, Ghana

Abstract

Aims: The study aimed at the quantification, isolation and characterization of hydrocarbon degrading bacteria in oil-contaminated and pristine soils. Methodology: Soil samples from petroleum hydrocarbon polluted sites at auto-mechanic workshops, a mechanic village, as well as pristine (control) soils, comprising of 14 sampling locations within Cape Coast Metropolis in the Central Region of Ghana were collected using standard sampling techniques. Collected soil samples were treated and cultured while enumerations, isolations and characterization of carbonoclastic bacteria associated were evaluated. Results: Bacterial populations isolated from hydrocarbon-polluted sites had higher aerobic counts ranging from 7.24-8.02 log10 cfu/g of soil when compared with the pristine sites (from 6.79-7.61 log10 cfu/g of soil). Also, soil samples from the mechanic village (8.76 to 7.48 log10 cfu/g of soil) recorded more bacterial counts than those from the mechanic garages (8.02 to 7.24 log10 cfu/g of soil). The calculated percentage profiles of all the hydrocarbon utilizing bacteria in the total culturable heterotrophic bacteria were low throughout the study, even though the percentage scores were all above 50%. A total of 19 hydrocarbon degraders were isolated. The isolates identified belong to the genera Pseudomonas, Proteus, Bacillus and Enterobacter. Conclusion: The outcome of the study based on the bacteria populations, identification profiles, coupled with their survival and multiplications in designated medium amended with crude oil as the carbon and energy sources, suggest their petroleum hydrocarbon degrading capabilities, hence may be used in bioremediation applications