Bioremediation of crude oil polluted soil by the white rot fungus, Pleurotus tuberregium (Fr.) Sing.

Bioremediation has become an attractive alternative to physicochemical methods of remediation of polluted sites. White rot fungi (WRF) are increasingly being investigated and used in bioremediation, because of their ability to degrade an extremely diverse range of very persistent or toxic environmental pollutants. The white rot fungus, Pleurotus tuberregium, was examined for its ability to ameliorate crude oil polluted soil. This was inferred from the ability of the polluted soil to support seed germination and seedling growth in Vigna unguiculata, at 0, 7 and 14 days post treatment. Results obtained from the present study showed that bioremediation of soil contaminated with crude oil was possible, especially when the fungus had been allowed to establish and fully colonize the substrate mixed with the soil. There were significant improvements in % germination, plant height and root elongation values of test plants, when seeds were planted 14 days post soil treatment. At 1 to 5% crude oil pollution, % germination values were comparable with the values in control plants in the 14 days treatment, and significantly higher than values obtained in the day 0 treatment. Also, at the highest level of crude oil pollution (15%), there was about 25% improvement in % germination value over the 0 day treatment. This trend of improvement in values was also observed for plant height, root elongation and biomass accumulation as well as decreased total hydrocarbon content.