BIODEGRADATION OF OIL REFINERY EFFLUENTS USING LOCALLY BACTERIAL ISOLATES

الملخص

There is an environmental risk developed around Al-Najef oil refinery area, which is located in southern west of Iraq, because this refinery does not contain a wastewater treatment unit and the polluted raw effluents are discharged directly to the surrounded areas. This research aims to isolate and identify some of a locally indigenous bacterial isolates which are capable to degrade of hydrocarbons. Water samples of effluents were collected and transported to laboratories of environmental researches centre - Ministry of Science &Technology –Baghdad .Water samples of effluents were cultivated on mineral salts media containing crude oil as source of carbon and energy. Five bacteria were isolated, three of them were found to have no ability to degraded hydrocarbons, and only two showed high potential to utilize crude oil (biodegradation). The two active isolates were identifying based on morphological, macroscopicallyand biochemical characterizes which were Pseudomonas aeroginosa and Alicagenesfaecalis. The pure culture of the tow isolates were cultivated on wastewater samples of the final effluents, where an increase of the biomass were observed by measuring the optical density (O.D) of the mineral salts medium. The results showed that, biodegradation of crude oil where consumed period less than consumed period of final effluents and, Alcaligenes faecalis has high potential of biodegradation than that of pseudomonas aeroginosa.