Biodegradation of hexachlorobenzene by basidiomycetes in soil contaminated with industrial residues

Hexachlorobenzene (HCB), one of twelve compounds classified as 'persistent organic pollutants' (POP), is a byproduct of the manufacture of organochlorine compounds, and is a cause of environmental contamination in several parts of the world. Its degradation by Brazilian basidiomycetes was studied through chromatographic analyses and monitoring of the production of (CO2)-C-14 from [C-14]HCB in the soil. Nineteen strains of basidiomycetes were found to be capable of tolerating concentrations of 5000 to 50,000 mg of HCB kg(-1) of soil. In spite of the low rates of production of (CO2)-C-14, Psilocybe cf. castanella CCB444 and Lentinus cf. zeyheri CCB274 were capable of removing nearly 3150 and 1400 mg of HCB kg(-1) from respective soil samples, during a 65-day study period.