Evaluation and Comparison of Soil Fungi Ability in Biodegradation of Crude Oil from Ahvaz and Omidiyeh's Oil Regions

The soil fungi play important role in degradation of organic substrates, especially in crude oil hydrocarbons. Due to lack of studies on use of fungi in degradation of petroleum hydrocarbons in Iran, fungi isolation from oily soils in Ahvaz and Omidiyeh was done to determine the relative growth of fungi on crude oil, and to measure the growth rate and degradation capacity of them in crude oil. The samples were cultured on Potato Dextrose Agar medium supplemented with Streptomycine and mineral salts medium (MSM) with 1% crude oil. Their abilities were compared for degradation of crude oil on liquid MSM and mycelia biomass and residual crude oil was measured. Finally, seven species selected from oily soils, and the abilities of Aspergillus terreus, A. flavus, Penicillium spp. and Fusarium spp. for degrading crude oil were compared. The highest level biomass was obtained by Penicillium spp. (71.40 ± 22.60 mg/50ml) and the lowest level by Fusarium spp. (24.0 ± 15.00 mg/50ml). The highest percentage of crude oil utilization was related to Penicillium spp. (46.10%) and the lowest Fusarium spp. (19.20%). All the organisms used in this study were indigenous to the environment from which they were isolated. In conclusion the biodegradation of contaminants is the best way to eliminate oil pollutions.