Ability of Agaricus bisporus, Pleurotus ostreatus and Ganoderma lucidum compost in biodegradation of petroleum hydrocarbon-contaminated soil

Use of the white rot fungi in bioremediation is effective in degrading of organic petroleum hydrocarbon-contaminated soil. The rate of degradation depends on nature of microflora and environmental characteristics of an oil-contaminated ecosystem. The spent mushroom compost of Agaricus bisporus, Pleurotus ostreatus and Ganoderma lucidum were used as inoculums (10%) for bioremediation of petroleum hydrocarbon-contaminated soil from the Esfahan Oil Refinery Company. The soils were kept at 25-28 degrees C and maintained at 60% water holding capacity. To provide the necessary aeration, the soils were tilled twice a week by shovel. Ecotoxicity testing was performed on dried soil sample, and residual oil was measured by gas chromatography. The petroleum hydrocarbons were degraded by all composts of white rot fungi. However, only A. bisporus showed a higher ability to degrade total petroleum hydrocarbons (71.5%). The results showed that the hydrocarbon remediation rate in all the treatments by A. bisporus, P. ostreatus and G. lucidum increased with time. Gas chromatography results showed total petroleum hydrocarbon decreased in all treatments. The result showed that spent mushroom compost degrades petroleum hydrocarbons residues in contaminated soil of Esfahan Refinery and reduced toxicity of this soil during 3months.