eng Science and Education Publishing International Journal of Environmental Bioremediation & Biodegradation 2333-8636 2015-02-26 3 1 23 27 10.12691/ijebb-3-1-4 IJEBB2015314 article Esedafe W. K. 1 Fagade O. E. 1 Umaru F. F. umarufred@gmail.com 2 Akinwotu O. 2 Department of Microbiology, University of Ibadan, Ibadan, Nigeria Department of Biological Sciences, Taraba State University, Jalingo, Nigeria The occurrence of polycyclic aromatic hydrocarbons (PAH) in refinery effluents is of great concern globally due to its persistence, recalcitrance and carcinogenicity. This study was aimed at bacterial degradation of polycyclic aromatic hydrocarbons (PAH) in untreated refinery effluent. Contaminated soil samples were collected from Warri refinery jetty while water sample was collected from Ekpan River and untreated effluent was collected from Warri refinery and Petrochemical Company. The total heterotrophic bacterial count ranged from 0.6 × 106 to 2.7 × 106 cfu/ml for soil samples and 3.2 × 106 cfu/ml for water sample. The hydrocarbon utilizing bacteria count ranged from 1.4 × 103 to 2.0 × 103 cfu/ml for soil samples and 1.0 × 103cfu/ml for water sample. Among the 41 bacterial isolates capable of utilizing crude oil vapour, 26 gave a positive emulsification activity on crude oil while only 3 were capable of degrading anthracene and phenanthrene. The three (3) PAH-degraders were characterized and identified as Pseudomonassp(SB), Achromobacterxylosoxidans(SB1) and Pseudomonassp(SB3). The percentage degradation of the polycyclic aromatic hydrocarbons in the refinery effluent after 360hours was highest in the mixed bacterial culture with 97.90% and this was followed closely by Pseudomonassp(SB) with 96% and Achromobacterxylosoxidans(SB1) having the lowest with 93.40%. http://pubs.sciepub.com/ijebb/3/1/4/ijebb-3-1-4.pdf refinery effluent polycyclic aromatic hydrocarbons biodegradation biosurfactant