Selection and Characterization of Bacteria Isolated from Petroleum Refining Effluents with Polycyclic Aromatic Hydrocarbons (PAHs) Removal Capacities and its Conditions

IN THIS STUDY, we evaluated the effect of different nutritional and environmental conditions on the percentages removal of PAHs present in petroleum refining effluent samples from the corrugated plate interceptor (API) of Cairo Oil Refining Co. (CORC), Egypt. Two hundred twelve and two hundred forty two bacterial strains were isolated from six petroleum refinery oil polluted effluents samples collected from CORC in summer and winter seasons, respectively which were selected due to their growing capacity in the presence of oil as sole carbon source. From these strains, four bacterial strains were further selected on the basis of their relatively good growing on hydrocarbon utilizing media, culture characteristics, and capacity to biodegrade PAHs. These bacterial isolates were identified on the basis of cell shape, cell arrangement, relation to oxygen and nutritional and biochemical characteristics. The four bacterial strains were found to belong to Pseudomonas oleovorans-W7DAFO22, Enterobacter cloacae-S7DAFI22, Pseudomonas stutzeri-S8API12 and Enterobacter aerogenes-W5OA31.They were capable of growing on the mineral salts media amended with crude oil as sole carbon source. Our results show that these strains can remove the PAHs by different percentages (%) at different pH values (4-9), NaCl concentrations (1-10%) and different nitrogenous and phosphorous sources. In conclusion, current sequence information provides the basis for a robust tool to estimate the PAHs degradation potential of different petroleum hydrocarbon contaminated sites undergoing in situ bioremediation.