ISOLATION AND IDENTIFICATION OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) DEGRADING BACTERIA FROM ARAK PETROCHEMICAL WASTEWATER

Abstract

Oil pollutions reduce the potential of soils for optimal use in agriculture and crop production. Polycyclic aromatic hydrocarbons are a large group of oil contaminants with carcinogenic, mutagenic, teratogenic effects. Phenanthrene, fluorine, anthracene and pyrene are tri and four-cyclic aromatic hydrocarbons that are found in high concentrations in polycyclic aromatic hydrocarbon-contaminated sediments, surface soils and waste sites. Today, Bioremediation is one of the most effective and affordable methods in degradation of these compounds from the contaminated environment. In this study, the ability of two native bacterial species isolated from Arak petrochemical wastewater (Pseudomonas aeruginosa and Serratia marcescens) were examined to degradation of phenanthrene, anthracene, fluorene and pyrene. The degradation potential of these compounds by mixed bacterial cultures was evaluated with protein assay and gas chromatography in the mineral salt medium containing 250 mg/l anthracene and fluorene, 200 mg/l phenanthrene and 150 mg/l pyrene as the sole carbon and energy source during 10 days’ incubation. Biochemical tests and 16s rDNA gene sequence analysis revealed that isolated bacteria are similar to Pseudomonas aeruginosa and Serratia marcescens with 99% similarity. The bacterial mixtures have good growth in PAHs compounds and could degrade more than of 98% of fluorine, 94% of anthracene, 97% of phenanthrene, 45% of pyrene and showed high potential to biodegradation of PAHs compounds in contaminated areas.