Direct dechlorination of chlorophenolic compounds by laccases from Trametes (Coriolus) versicolor

Laccase-type phenol oxidases are the principal oxidative enzymes secreted by the white-rot basidiomycete Trametes (Coriolus) versicolor. Numerous reports indicate that these laccase enzymes can oxidize, polymerize, and, under some conditions, cleave a wide variety of biological and synthetic phenolic compounds. Since we had recently observed that the complete T. versicolor fungal system could lower the adsorbable organic halogen (AOX) of chlorinated kraft bleachery effluents, we wondered if any of the laccase protein fractions secreted by T. versicolor could, per se, directly mineralize the organochlorine from toxic chlorophenolics commonly found in these effluents. Our results indicate that each of the fungal laccase proteins tested can rapidly partially dechlorinate a number of toxic polychlorinated phenols and guaiacols.