Biodegradation of pentachorophenol by tropical basidiomycetes in soils contaminated with industrial residues

The ability of tropical Brazilian basidiomycetes to degrade pentachlorophenol (PCP) in soils from areas contaminated with organochlorine industrial residues was studied. Thirty-six basidiomycetes isolated from different tropical ecosystems were tested for tolerance to high PCP concentrations in soil. Peniophora cinerea and Psilocybe castanella, two strains of Trametes villosa, Agrocybe perfecta, Trichaptum bisogenum and Lentinus villosus were able to colonize soil columns containing up to 4600 mg pentachlorophenol kg(-1) soil. The first four species were inoculated into soil containing 1278 mg pentachlorophenol kg) 1 soil supplemented with gypsum and sugar cane bagasse. P. cinerea, P. castanella, T. villosa CCB176 and CCB213 and Agrocybe perfecta reduced the PCP present in the contaminated soil by 78, 64, 58, 36 and 43%, respectively, after 90 days of incubation. All fungi mineralized [C-14] pentachlorophenol, mainly P. cinerea and T. villosa with the production of 7.11 and 8.15% (CO2)-C-14, respectively, during 120 days of incubation. All fungi produced chloride ions during growth on soil containing PCP, indicating dehalogenation of the molecule. Conversion of PCP to pentachloroanisole was observed only after 90 days of incubation in soils inoculated with A. perfecta, P. cinerea and one of T. villosa strain. The present study shows the potential of Brazilian fungi for the biodegradation of toxic and persistent pollutants and it is the first to report fungal growth and PCP depletion in soils with high pentachlorophenol concentrations.