Population dynamics and distribution of hydrocarbon utilizing bacteria in Automobile workshops within Uyo metropolis, Akwa Ibom State

Abstract

Laboratory studies were carried out to assess the bacterial population dynamics and distribution in composite soil samples collected from five (5) different automobile workshops at various locations (Ikpa road, Nwaniba road, Udi street, Idakokpo lane and Mechanic village) within Uyo metropolis. The hydrocarbon utilizing bacteria were isolated and characterized from the soils of automobile workshops using cultural techniques. The total heterotrophic bacterial count (THBC) ranged from 2.5 × 10⁵ to 8.0 × 10⁵ CFU/g of soil sample, while the hydrocarbon utilizing bacterial count (HUBC) ranged from 2.5 × 10⁴ to 4.4 × 10⁴ CFU/g of soil sample. The bacterial isolates which were both Gram positive and Gram negative belonged to the genera; Bacillus, Flavobacterium, Achromobacter, Micrococcus, Citrobacter and Acinetobacter. The total heterotrophic bacterial count (THBC) and hydrocarbon utilizing bacterial count (HUBC) were higher in Ikpa road automobile workshop and Nwaniba road automobile workshops respectively. Bacillus species was found to be present in all the soil samples analysed thus had the highest frequency 5(28%) of occurrence while Achromobacter species had the lowest frequency 1(6%) of occurrence. The presence of these organisms in soils contaminated with spent and unspent lubricating oil and their subsequent growth in enrichment medium supplemented with 1% spent lubricating oil suggest their hydrocarbon utilizing potential, hence, their possible use for the bioremediation of soils impacted with lubricating oil.

Keywords: automobile workshops, hydrocarbon utilizing bacteria, bioremediation, enrichment medium,
lubricating oil