EFFECTS OF PHYSICAL PARAMETERS AND ALGORITHM OF PETROLEUM HYDROCARBONS UTILIZATION BY SOME BACTERIAL ISOLATES FROM BONNY, RIVERS STATE NIGERIA

The ability of some bacterial isolates to utilize crude oil and the effects of pH and various nitrogen sources on the growth and utilization of hydrocarbons were investigated. A total of six bacterial isolates were isolated. These include two different species of Bacilli, three different species of Pseudomonas and Klebsiella species. The effects of pH on the growth of the isolates showed that Pseudomonas sp (A2) had the highest growth of about 2.25?105 cfu/ml at pH 6.5. Baciliussp (A5), Klebsiellasp (A1) recorded growths of 2.04?105 and 1.70?105 cfu/ml at pH 7.5 and 7.0 respectively. These isolates were able to utilize and grow on different nitrogen sources containing ammonium sulphate((NH4)2SO4), sodium nitrate (NaNO3), and ammonium chloride (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. The effects of pH on the utilization of Bonny light crude oil 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 77.5%, 66.8%, and 54.2% after 28 days of incubation for Pseudomonas, Bacillus and Klebsiella species respectively.