Environmental assessment of petrophilic bacteria associated with bioremediation and biodegradation of engine oil contaminated soil in Maiduguri

Abstract

Soil contamination by petroleum hydrocarbons is a major problem resulting from activities related to petroleum industry, automobile service stations and accidental release of oil in the soil. Bioremediation/biodegradation can be considered as an effective aid to clean up oil spills, aside from conventional methods that are uneconomical and produce residues that harm the surrounding biota. There are an estimated over 250 mechanic shops with more than 5000 technicians in Maiduguri. Mechanics working therein frequently spill oil which is a potent source of immunotoxicants and carcinogenic to humans and animals. The aim of this study was to screen for petrophilic bacterial isolates from engine oil contaminated soil, that can utilize crude oil as sole source of carbon for growth in Maiduguri Metropolis. Ten isolates from engine oil contaminated soils in Bola and Tashan Kano areas of Borno State were obtained. The bacteria were individually cultured in Bushnell Haas Mineral Salt Medium devoid of carbon source except for crude oil for 21 days at 370C. Bacterial growth from visible increased turbidity was enumerated by
CFU/g on nutrient agar. Pseudomonas sp. isolate exhibited relatively higher ability to grow on crude oil with TNTC followed by Bacillus sp., 6.7×10⁴, Arthrobacter sp.,6.5×10⁴, Flavobacterium sp.,6.2×10⁴, Pseudomonas sp., 6×10⁴, Nocardia sp.,5.9×10⁴, Acinetobacter sp., 5×10⁴, Bacillus sp., 5×10⁴. Proteus sp., 4.7×10⁴ and Flavobacterium sp. 4×10⁴. It is therefore concluded that all the bacterial genera present in this study are effective hydrocarbon oil degraders.