Evaluation of Bioremediation of Bacteria Degrading Petroleum Compounds Isolated from Petroleum Contaminated Soils in the Presence of Phenanthrene

Polycyclic aromatic hydrocarbons (PAHs) are a group of environmental contaminants in the soil that have caused concerns due to toxicity, mutagenic and carcinogenic effects. The bioremedial process has been considered as a suitable solution for the improvement of contaminated soils by many researchers. Therefore, the aim of this study was to isolate, identify and evaluate the growth potential of bacteria degrading petroleum compounds isolated from soil contaminated with petroleum products in the presence of phenanthrene for biological improvement. In this study, 25 soil samples were first collected from 0-35 Cm depth of oil-contaminated areas located in southern Iran (the Bushehr region) and then isolated from suitable culture media of oil-degrading bacteria. Afterward, the isolated bacteria were identified by biochemical methods such as oxidase test and catalase test, and microbial methods such as gram staining, spores staining, and fluorescence staining. In this study, out of 60 oil-degrading bacteria, 19 bacteria called PDB 1-19 were determined in the presence of phenanthrene. Finally, PDB 19 Chryseobacterium spp, PDB 8 Sphingobacterium spp, PDB 13 Acinetobacter johnsonii, and PDB 10 Achromobacter xylosoxidans were selected as the most efficient bacteria. The results of this study show that by identifying and screening effective bacteria, utilizing their microbial potentials, and creating optimal conditions, they can be used to bioremediate oil-contaminated soils at industrial and applied scales.