Objective: Decontamination of petroleum and its derivatives from natural sources is a very critical task due to highly polluting properties of the petroleum. Removal or conversion to different less toxic or non-toxic forms of oil hydrocarbons via bacteria, known as “bioremediation” has become an important research area. In this study, the aim was to determine the bacteria which have the abilty of degradation of oil and oil derivatives by scanning strains of 698 marine bacteria isolated from Marmara and Black Sea.

Material and Method: Within this context, firstly, 7 selected isolates known to degrade oil were incubated for 30 days at different concentrations and larger scale in crude oil and thickness of the oil layer in millimetres and morphological changes observed were recorded on a daily basis. After 30 days of experimental period, samples were prepared for gas chromatography-mass spectrometry analysis. In the last phase of the study, seven bacterial isolates were tested by the VITEK 2 Compact Automatic Identification System for pre-identification.

Results: Based on experimental results, bacteria were able to survive and degrade the crude oil even at the highest petroleum concentrations. The highest reduction in the petroleum layer thickness was observed for 333, A87 and 331 isolates. Quinoline (C9H7N) was detected as the degradation product of petroleum, in all isolates. VITEK system predefined 5 isolates including Serratia plymuthica, Enterococcus faecalis, Klebsiella pneumoniae subsp. ozaenae, Staphylococcus lentus, and Staphylococcus sciuri. As a result the candidate bacteria that may be used for biological remediation of pollution of our sea arising from oil have been determined.

Conclusion: The study is one of the original and pioneering works in terms of showing that existing bacteria in Marmara and Black Sea can be used for bioremediation purposes.