Bioremediation of refinery wastewater using immobilised Burkholderia cepacia and Corynebacterium sp and their transconjugants

When oil spill occurs, it poses serious toxic hazards to all forms of life. Mixed culture of Burkholderia cepacia and Corynebacterium sp isolated from refinery sludge using selective enrichment technique was used for bioremediation of refinery wastewater in a laboratory-scale bioreactor. Physicochemical parameters of both raw and treated water were as determined and compared with Federal Environmental Protection Agency (FEPA-limit, Abuja, Nigeria) to asses the efficiency of the bioremediation process. Each of the bacterium was screened for the presence of plasmid DNA and for the involvement or otherwise of plasmid in the bioremediation of wastewater. The immobilised cells showed percentage decrease in chemical oxygen demand (97%), biochemical oxygen demand (94%), phenol (98%), total petroleum hydrocarbon (79%), oil and grease (90%) of the refinery waste water after 20 days of treatment while their transconjugants showed the multiplicative effect by achieving the same percentage after 10 days of treatment. Therefore, the findings revealed that bioaugmentation of wastewater using transmissible catabolic plasmid will enhance efficiency of the bioremediation by spreading the plasmid among indigenous microbial community either through horizontal gene transfer or transformation.