Removing of Benzo[a]pyrene using the Isolated Fungi from Petroleum-polluted Soils

Abstract

Benzo[a]pyrene, belonging to polycyclic aromatic hydrocarbons, is one of the most important industrial pollutants. This research was aimed to evaluate some fungal strains, with petroleum removing potency, for degradation of BaP from BaP-polluted media and also evaluation of Enzyme activity and protein content in the fungi growing in BaP-polluted media. In a field study seven fungal specie were isolated from Tehran oil refinery and cultured in potato dextrose agar (PDA) media containing 30, 60 and 90 (mg/kg) BaP for adaptation of the fungal strains. Removing of BaP was measured after 45 days growth of the fungal colonies under different concentrations of BaP pollution in PDA media and soil. Peroxidase and catalase activity, and protein content were compared in the fungi growing in BaP-polluted media and control ones. The results showed that all the isolated fungi were able to growth in the BaP containing media and could remove BaP from the media. The highest removal efficiency was determined for Fusarium acuminatum (93%). Similar data obtained when the fungus used for bioremediation of BaP-polluted soil (91%). Total protein content and enzymatic activity (Peroxidase and Catalase) were increased with increasing of BaP pollution. The highest catalase activity was measured in F. acuminatum growing in the media containing 90 mg/kg BaP (2.2×10-2 unit/mg protein) and the highest (5× 10-3 unit/mg protein) peroxidase activity for Alternaria alternata. Protein content in the fungi was increased with increasing of BaP pollution. In F. acuminatum, the lowest amount of total protein was observed in the control sample (1×10-3 mg/g FW) and the highest amount was belonging to the group treated by 90 mg/kg BaP (7.5×10-3 mg/g FW). It concluded that F. acuminatum showed the highest catalase activity, highest total protein content and also the highest BaP removal efficiency from both BaP-polluted media and soils.