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 × 10 6 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