Experimental Investigation of Biological Removal of Benzene and Toluene Using Aspergillus terreus and Exophiala xenobiotica Fungi

The role of great industries such as oil, gas petrochemical is essential in the world economy, however, the most problem of these industries is the abandoned pollutants in the environment. In this study, the removal of two major oil pollutants, benzene, and toluene was investigated in the presence of two new and native fungi called Aspergillus terreus and Exophiala xenobiotica. The factors affecting the removal process consist of temperature, time, concentration and pH. The results showed that the highest adsorption of pollutants occurs at 25 ℃ within 10 days of contact time with fungus A. terreus and 25 days for fungus E. xenobiotica in a way that both pollutants have a concentration of 5 ml/lit and pH=7. A comparison of the performance of two fungi on the removal of pollutants showed that in the condition in which the effect of concentration, contact time, and the temperature was investigated E. xenobiotica is successful in removing benzene and A. terreus showed better performance when the effect of pH was evaluated. In contrast, in the removal of toluene, the A. terreus showed better performance in all conditions. Finally, based on the result of this research, it could be concluded that the bioremediation process using new fungi is a promising and environmentally compatible solution to eliminate oil pollution. In general, based on the results obtained under the optimum conditions of all four parameters, A. terreus had the best performance for benzene and toluene contaminants with the removal of 68.35% and 84.27%, respectively.