Comparative Studies on Biodegradative Abilities of Pleurotus ostreatus and P. pulmonarius in Soils Contaminated with Crude and Used Engine Oils

Abstract

Crude and used engine oil degrading ability of two white rot fungi Pleurotus ostreatus and P. pulmonarius were investigated for six months. One hundred grams of sterilized soil moistened with 75% distilled water (w/v) were weighed into 9 × 9 × 4 cm (350 cm3) jam bottles and mixed thoroughly with bonny light crude oil and used engine oil at different concentrations (0%, 5%, 10%, 15%, 25% and 30%), separately. Each bottle was then inoculated with two agar plugs of a vigorously grown mycelium of P. ostreatus and P. pulmonarius using a sterile cork borer. The bottles were incubated at room temperature for 6 months. The mycelia-ramified waste was separated from soils and analysed for physicochemical parameters such as organic matter, carbon, nitrogen, phosphorus, potassium, pH and total hydrocarbon content, (THC) after drying. The organic carbon, nitrogen and phosphorus contents in contaminated and inoculated soils were increased after six months. However, decrease in potassium, pH and THC occurred in these soils after the period of investigation. P. ostreatus reduced the initial THC to 8% and 9% in soils contaminated with 20% of crude and engine oils, respectively, which was lower than that of P. pulmonarius. The two white rot fungi could be exploited in bioremediation of soils contaminated with bonny light crude and used engine oils.