Anyanwu, Charles Obinna2026-03-242026-03-242019-12Anyanwu, C. O. (2019). Determination of petroleum product- emulsification potentials of some bacterial isolates from Bonny River, Rivers State [Unpublished Master's Thesis]. Federal University of Technology, Owerri, Nigeriahttps://repository.futo.edu.ng/handle/20.500.14562/2465This thesis is for the award of Master of Science (M.Sc) in BiotechnologyIn this study, the petroleum product-emulsification potentials of some bacteria isolated from Bonny River and its river bank was investigated. A total of ten (10) bacteria isolates, belonging to six genera namely Bacillus, Pseudomonas, Klebsiella, Escherichia, and Salmonella were isolated. Emulsification assay carried out include drop collapse, oil spread and emulsification index test on the isolates using crude oil, kerosene, diesel and coconut oil as the sole carbon source. Emulsification index assay showed statistical significance (p<0.05) in the emulsification potentials of the isolates. Klebsiella sp C4 showed the best emulsification activity with 53.3%, 58.2%, 56.0% and 51.9% emulsification index using diesel oil, coconut oil, kerosene and crude oil respectively. It was followed by Pseudomonas sp HC4 with 51.0%, 48.0%, 54.0% and 49.0% emulsification activity using diesel oil, coconut oil, kerosene and crude oil respectively, Bacillus sp HC6 had emulsification indices of 47.0%, 51.0%, 48.2% and 46.7% for diesel, coconut oil, kerosene and crude oil respectively as sole carbon source. The effects of pH on the growth of the isolates showed that Pseudomonas sp HC4 had the highest growth of about 2.25×105 cfu/ml at pH 6.5. Bacilius sp HC6, Klebsiella sp C4 recorded growths of 2.04×105 and 1.70×105 cfu/ml at pH 7.5 and 7.0 respectively. Statistical analysis showed no significant difference (p>0.05) in the growth of the isolates at the various pH ranges tested. These isolates were able to utilize and grow on different nitrogen sources containing ammonium sulphate ((NH4)2SO4), sodium nitrate (NaNO3), and ammoniumchloride (NH4Cl). NH4Cl was the best utilized nitrogen source with growth of 2.37×105 , 2.17×105 , and 1.93×105 cfu/ml for Pseudomonas, Bacillus and Klebsiella species respectively. Statistical analysis showed a significant difference (p<0.05) between the utilization of nitrogen sources and the growth of the isolates. The effects of pH on the utilization of Bonny light crude oil showed no statistical significance (p>0.05) and revealed percentage utilization of about 76%, 68%, and 58% at pH of 6.5, 7.5 and 7.0 respectively for Pseudomonas, Bacillus and Klebsiella species. Percentage utilization of about 67%, 63%, and 51.8% were recorded for Pseudomonas, Bacillus and Klebsiella species when grown on mineral salt media supplemented with NH4Cl. The isolates were tested for their ability to utilize bonny light crude oil using the gravimetric method. The percentage utilization of all the isolates ranged between 54.2% and 77.5% after 28 days of incubation for Pseudomonas, Bacillus and Klebsiella species respectively.enAttribution-NonCommercial-ShareAlike 4.0 InternationalEmulsificationemulsification indexdrop collapseoil spreadDepartment of BiotechnologyMaster’s Thesis