Isolation and Identification of Hydrocarbons- Degrading Bacteria from Panteka Stream, Kaduna, Nigeria, and Assessment of their Potential for Bioremediation

Abstract

Water bodies become hydrocarbon-polluted when petroleum and other toxic organic matters are discharged into them. Panteka, located in northern Kaduna, Nigeria, is home to Panteka market, which is an industrial hub where different kinds of automobile spare parts are sold and mechanic workshops are situated. The Panteka stream flows through an entry point at Rafin guza, through Panteka market and towards the National Eye Centre. The indiscriminate disposal of spent engine oils and the discharge of other untreated effluents from car servicing workshops into the Panteka stream can lead to hydrocarbon contamination. Consequently, there is a need to identify these hydrocarbons and determine the capability of bacteria isolated from the stream to degrade the hydrocarbon pollutants. Using the pour plate method, and Bushnell Haas agar supplemented with 1% used engine oil, five bacterial isolates with the potential to degrade hydrocarbons were identified as Streptococcus pnuemoniae, Klebsiella pneumoniae, Shigella dysenteriae, Streptococcus pyogenes and Salmonella enterica. Salmonella enterica was confirmed by 16S rRNA gene sequencing and Basic Local Alignment search tool (BLAST) with a similarity index of 99%. The ability of the bacterial isolates to tolerate the spent engine oil was determined by turbidi metry. The results show that all the five bacterial isolates were able to tolerate the 1% (v/v) concentration of the spent engine oil. The highest growth rates (O.D 0.565 and O.D 0.695) were obtained from the pure cultures of Streptococcus pyogenes and the mixed bacterial consortium, respectively. The potentials of the bacteria to degrade hydrocarbons in the stream was analysed using Gas Chromatography Flame Ionization Detector (GC-FID), and the results showed reduction of the Total Petroleum Hydrocarbon (TPH) content from 6,056 mg/ml to 100.17 mg/ml (98.3% degradation) after 28 days of treatment with the mixed bacterial culture. The hydrocarbon fractions degraded were n-Nonane, n-Decane, nUndecane, nDodecane, n-Tridecane, n-Tetradecane, n-Heptadecane, Pristane, n-octadecane, Phytane, n-Eicosane, n-Tricosane, n-Tetracosane, n-Octacosane, n-Triacontane, n-Dotriacontane, nTritriacontane, n-Heptriacontane; while n-Pentadecane, n-Hexadecane, n-Nonadecane, nHeneicosane, n-Docosane, n-Pentacosane, n-Hexacosane, n-Heptacosane, n-Nonacosane, nHentriacontane, n-Tetratriacontane, n-Pentatriacontane, and n-Hexatriacontane were not degraded. This study shows that these bacterial strains isolated from the Panteka stream have great potential for bioremediation of the hydrocarbons found in the stream.