Changes in microbial population during mycoremediation of diesel oil contaminated soil

Abstract

The rates of bioremediation of diesel oil-contaminated soil were studied for a period of 12 weeks through changes in microbial population Two kilograms of soil moistened with 10% distilled water (w/v) was mixed thoroughly with diesel oil (5 and 10% concentrations respectively), and 3.6 × 10⁶ ml spores of each fungal consortium were inoculated in the soil and exposed to natural conditions in the field for three months. Two controls without fungal inoculants were set up: C1OS (oil + soil-control 1), and C2OS (soil only-control 2). The results revealed that the populations of diesel oil utilizing microorganisms were higher at both 5 and 10% diesel oil pollution in the three soil amendments compared to the unamended control soil. The bacterial isolates were identified as species of Pseudomonas, Bacillus, Micrococcus, Staphylococcus and Escherichia, while the fungal isolates were identified as species of Aspergillus, Scopuloropsis, Cephalosporium, Penicilluim, Geotrichum, Mucor, Trichophyton and Microsporum. The pH (5.02 – 6.18) of the amended soil was lower compared to the unamended control soil (5.01 – 6.49) after 12 weeks. The moisture content of the amended soil (10.09 to 16.42%) was higher compared to the unamended control soil (8.14 to 11.39%) after 12 weeks. The results suggest that the isolates identified utilized the diesel oil as sources of carbon and nitrogen to proliferate.

Keywords: Bioremediation, Consortium, Contaminated, Mycoremediation, Soil