Activity of Phanerochaete chrysosporium during degradation of diesel fuel-contaminated soil under solid-state fermentation: CO2 production and ligninolytic enzymes

Diesel fuel is a complex petroleum compound that is considered an important and serious risk for organisms and their environment. There are different methods for soil cleaning from this compound, of which bioremediation is one of the best. This study was conducted to investigate the efficiency of Phanerochaete chrysosporium fungus in bioremediation of diesel fuel contaminated soil under oxygen-deficient conditions. In this study, soil samples free of petroleum compounds were manually contaminated with 3000 mg/kg of diesel fuel and incubated for 60 days at 30°C in a dark chamber. The amounts of CO₂ production, microbial growth, manganese peroxidase, and lignin peroxidase enzyme activities were measured every 10 days. The results indicated that the amount of CO₂ production in both pure and mixed cultures increased significantly from the beginning of the experiment to the 40th day, which was 22.96 and 25.53 mg/g/w, respectively. Manganese peroxidase and lignin peroxidase enzymes also first reached their maximum values on the 40th day, which were 225 U/L and 31.5 U/L, respectively, and then decreased. The average percentage of TPH degradation on different days showed that the biological decontamination rate of diesel fuel in pure and mixed culture was 79.62 and 83.17%, respectively, within 60 days. By comparing the biodegradation rate with other data, we concluded that P. chrysosporium can degrade diesel fuel under fermentation conditions and use its compounds to provide energy and carbon.