Study of the removal of Polycyclic Aromatic Hydrocarbons by a halotolerant bacteria isolated from Dehloran Oil-contaminated soil

Soil contamination by petroleum compounds and salt often occurs simultaneously. The aim of this study was the isolation of halotolerant bacterial strains with the ability to remove different concentrations of polycyclic aromatic hydrocarbons (PAHs).

In the present original study, petroleum-contaminated soil samples were collected from Dehlran area. To isolate bacterial strains degrading PAHs, PAHs- enriched media were used as the sole source of carbon and energy. The ability of the isolates to tolerate different salt concentrations was investigated. Based on its capacity to produce biosurfactants, a suitable bacterial strain was chosen and the biodegradation of various types of PAHs was evaluated. The effects of the molecular weight and initial concentration of different types of PAHs on the strain’s cell growth and biodegradation were investigated.

Among the isolates, Labedella gwakjiensis strain KDI, with the ability to grow at concentrations greater than 3% salt and produce biosurfactants, was selected. The results demonstrated that this strain could biodegrade various types of PAHs, and that the molecular weight and initial concentration of PAHs, which have a direct effect on cell growth, indirectly affect the biodegradation rate.

Salt is considered as a deterrent in biodegradation. Hence the use of halotolerant bacterial strains capable of biodegrading PAHs is critical in removing these pollutants from the environment.