Biodegradation of Pentachlorophenol in Soil Amended with the White Rot FungusPhanerochaete chrysosporium

Abstract

The effects of bioaugmentation of pentachlorophenol (PCP)-contaminated soil with the fungus Phanerochaete chrysosporium was evaluated using a chemical mass balance approach. While there was no observed PCP removal for the unamended soil, 93% of the initial mass of PCP was removed within 56 days in soil amended with P. chrysosporium-inoculated corncobs. Within the same incubation period, approximately 58% of the initial mass of PCP was removed from soil amended with uninoculated corncobs. PCP removal followed first order kinetics with rate constants of 0.04 ± 0.017 day−1, 0.06 ± 0.015 day−1, and 0.018 ± 0.006 day−1 for PCP contaminated soils amended with fungus-inoculated sterile corncobs, fungus-inoculated nonsterile corncobs, and uninoculated nonsterile corncobs, respectively. Comparison of the nonsterile systems indicated that the presence of the fungus increased the first order removal rate constant by more than 200% compared to the uninoculated system. The extent of PCP mineralization after 56 days of incubation was 7%, 17%, and 8% for PCP contaminated soil amended with fungus-inoculated sterile corncobs, fungus-inoculated nonsterile corncobs, and uninoculated nonsterile corncobs, respectively. The extent of bound residue formation was 13%, 19%, and 27% for PCP contaminated soil amended with fungus-inoculated sterile corncobs, fungus-inoculated nonsterile corncobs, and uninoculated nonsterile corncobs, respectively. Mass balance analyses indicated that soil aeration may enhance removal of PCP and/or its chemical intermediates through a process of facilitated transport and/or volatilization.