Degradation of Bisphenol A by Purified Laccase from Trametes villosa

Degradation of bisphenol A (BPA), an endocrine-disrupting chemical, was studied with a purified laccase from the basidiomycete Trametes villosa. SDS--polyacrylamide gel electrophoresis of the purified laccase gave one single band with a mobility corresponding to MW 65 kDa. The absorption spectrum showed the characteristics of a blue copper protein with a maximum peak at 600 nm. HPLC analysis revealed that 2.2 micromol BPA were degraded by incubation with 1.5 units of the purified laccase in a total volume of 1.0 ml at pH 6.0 and 60 degrees C for 3 h. The enzyme reaction proceeded rapidly without requirement of mediators for the electron transfer. Isolation and identification of several reaction products are in progress, in which one product was identified as 4-isopropenylphenol by a gas chromatography--mass spectrophotometer.