USE OF LIGNIN-DEGRADING FUNGI IN THE DISPOSAL OF PENTACHLOROPHENOL-TREATED WOOD

The lignin-degrading fungi Phanerochaete chrysosporium, P. sordida, Trametes hirsuta, and Ceriporiopsis subvermispora were evaluated for their ability to decrease the concentration of pentachlorophenol (PCP) and to cause dry weight loss in PCP-treated wood. Hardwood and softwood materials from PCP-treated ammunition boxes that were chipped to pass a 3.8-cm screen were used. All four fungi caused significant weight losses and decreases in the PCP concentration. The largest PCP decrease (84% in 4 weeks) was caused by T. hirsuta, and the smallest decrease was caused by C. subvermispora (37% in 4 weeks). After 4 weeks, the fate of spiked C-14[PCP] in softwood chips inoculated with T. hirsuta was as follows: 27% was mineralized, 42.5% was non-extractable and bound to the chips, 23.5% was associated with fungal hyphae, and 6% was organic-extractable. Decreases of PCP by P. chrysosporium and P. sordida averaged 59% and 57% respectively. PCP decreases caused by Phanerochaete spp. were not significantly affected by wood type or sterilization and were primarily due to methylation of PCP that resulted in accumulation of pentachloroanisole. Softwood weight losses caused by T. hirsuta, P chrysosporium and C. subvermispora were respectively, 24, 6.5, and 17%, after 4 weeks. These weight losses are comparable to reported weight losses by these organisms in non-treated softwood. Nutrient supplementation significantly increased weight loss but not percentage decrease of PCP. The results of this research demonstrate the potential for using lignin-degrading fungi to destroy PCP-treated wood.