Isolation and Characterization of Hydrocarbon-Degrading Bacteria from Petroleum Storage Facilities in the Kumasi Metropolitan Area.

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Hydrocarbon degrading microorganisms isolated from five different petroleum storage facilities in the Kumasi Metropolitan area were investigated. A total of five bacterial isolates were obtained. Culture-based techniques i.e., isolation, enumeration, purification, biochemical tests were carried out to obtain the aforementioned organisms. The isolates (Pseudomonas cepacia, Pseudomonas aeruginosa, Enterobacter, Proteus and Bacillus), were from petroleum sludge of gasoline, diesel and kerosene. The research also focused on screening for the potentials of the isolates in utilizing the following hydrocarbon substrates (gasoline, diesel and kerosene) in Bergs Mineral Salt Medium (BMSM). The effects of different nutrients (soy and pito waste) supplementation on biodegradation indices were also assessed. The biodegradation indices that were evaluated include Optical Density (OD 600 nm), floating abilities of the isolates, emulsification (E24) indices and Gas Chromatography (GC) profiles. The isolates were able to reduce the hydrocarbon substrates considerably as revealed in the percent area report values over the time frame of two weeks compared to the control (abiotic). The results from the GC profiles showed that all the isolates had well above 80% reduction in the hydrocarbon substrates. Enterobacter cloacae showed the greatest potential with respect to gasoline degradation efficiency under soy supplement thus (99.66%) followed closely by consortium (soy added), Proteus mirabilis (soy added) had 99.4%, followed lastly by Bacillus firmus (97.2%). For diesel degradation, Pseudomonas cepacia (soy added) and the consortium (no nutrients added) were the same with respect to the degradative efficiency of 99.80% followed by Enterobacter cloacae (soy added) with 99.6%, Pseudomonas aeruginosa and consortium each gave an efficiency of 99.55% with soy added. P. Aeruginosa gave the least efficiency of 93.0% under pito waste inclusion. For kerosene degradation studies, Enterobacter cloacae (soy added) gave 96.0%; consortium (no nutrient added) gave 95.60%; Enterobacter cloaeca (no nutrient added) recorded 95.5% with the least efficient being Bacillus (soy added) recording 83.4%. Compared to the controls these degradation efficiencies were relatively high.
A thesis submitted to the School of Graduate Studies, Kwame Nkrumah University of Science and Technology in partial fulfilment of the requirement for the award of Master of Science degree in Biotechnology, March-2013
Hydrocarbon contamination, Bacterial isolates, Biostimulation, Gas chromatography