Removal Efficiency of Total Petroleum Hydrocarbons from Water by Pseudomonas aeruginosa A Case of Lake Albert, Uganda

Abstract

Oil exploration and production has recently intensified in the Albertine Graben of Uganda with no emphasis placed on remediation methods to combat the spill that will happen. The current study was done to explore the extent to which Pseudomonas aeruginosa can remediate petroleum hydrocarbon (PH) contaminants of Lake Albert water in western Uganda. 2 liters of water of Lake Albert were collected and kept in sterile flask. The water was placed on Ice in a cooler box and transported to Makerere University Chemistry pesticide laboratory. The sample was then refrigerated for 10 hours. Ten percent (10% m/v) (100 g/L) contamination was intentionally made for this Lake Albert water sample using selected various amounts of PHs of known amounts. A sample of petroleum hydrocarbon contaminated water (10 ml), was quantitatively placed in a 250 ml flask containing a nutrient broth (100 mL). An aliquot of Pseudomonas aeruginosa starter culture (3.0 × 107 CFU)/mL) was introduced. Amount of PHs left after the remediation was quantified using GC-MS unresolved complex mixtures approach. Pseudomonas aeruginosa significantly (p<0.05) remediates the petroleum hydrocarbon from lake albert water with the highest removal efficiency registered at the end of the sixth day of the remediation process and this is 89.3% of n-hexane soluble PH. At the end of 6 days, the 100 g/L of PHs that was introduced on water was reduced to 10.7 g/L (89.3%) after inoculating with 3.0 x 107 CFU/mL at the beginning of the experiment. The control experiment also showed presence of PHs ranging from 9-32 g/L. In conclusion, the Lake Albert water is already contaminated with PHs. However, Pseudomonas aeruginosa can remediate petroleum hydrocarbon (PH) contaminants significantly.