The Study of Aspergillus niger as a Potential Bioremediator of Iron and Hydrocarbons in a Complex, Co-Contaminated, Soil Environment

The purpose of this study was to investigate whether Aspergillus niger, a common fungus found in the environment, could simultaneously break down iron and hydrocarbons as a cost-effective and eco-friendly method of bioremediation. It was hypothesized that as the amount of iron and diesel in the soil increases, the effectiveness of A. niger would remain unaffected due to a rise in metabolic efficiency, causing increased production of organic acids and enzymes that break down contaminants into simpler compounds for energy. Ferrous ammonium sulfate was dissolved in water and added in different concentrations to 90 cups along with varying volumes of diesel. Trials were divided into groups with group one (EG1) containing 0.1 g of Fe and 0.5 mL of diesel and group two (EG2) containing 0.3 g of Fe and 1 mL of diesel. Aspergillus niger was then added to the cups and left to bioremediate for 14 days. Results were measured using hydrocarbon test strips and redox titrations using potassium permanganate. For the control group, the mean was 22.34 mg/kg (SD = 7.81), for EG1, the average was 109.56 mg/kg (SD = 24.31), and for EG2, the average was 152.11 mg/kg (SD = 41.39). Hydrocarbon removal was not effective or significant at χ2(3, N =30) = 5.37132, p = .147. Iron removal was effective at F(2, 87) = 161.31, p < .001. In conclusion, the experiment showed that Aspergillus niger was effective in the bioremediation of iron, but not hydrocarbons.