Removal of estrogenic activity from endocrine-disrupting chemicals by purified laccase of Phlebia tremellosa

A white-rot basidiomycete, Phlebia tremellosa, produced a laccase that showed increased activity during degradation of phthalates. A laccase was purified through the ion exchange chromatography and preparative gel electrophoresis, and the estimated molecular weight was 75 kDa. The optimum pH and temperature of the purified laccase was pH 4.0 and 20 degrees C, respectively. The K(m) value of the enzyme was 55.7 microM, and the V(max) was 0.0541 OD min(-1) U(-1) for o-tolidine. Purified laccase reduced the estrogenic activity of four different endocrine-disrupting chemicals. However, this effect was reduced by a laccase inhibitor, kojic acid, which confirmed that the laccase was involved in the removal of estrogenic activity.