Abstract
Fomes sclerodermeus was grown on semi‐defined media based on yeast extract, peptone and glucose (YPG). The fungus produced a minimum basal level of laccase activity irrespective of culture medium. The highest laccase production (20 U cm^−3^) was obtained in cultures supplemented with CuSO~4~. Manganese peroxidase (MnP) could only be detected when MnSO~4~ was added to the medium. None of the aromatic compounds tested stimulated further laccase or MnP production. Laccase and MnP stimulated by Cu^2+^ or Mn^2+^ respectively were purified. Two different laccase isoenzymes with the same molecular mass (67 kDa) and N‐linked carbohydrate content (3%) and a slight difference in their p__I__ values (3.41 and 3.48) were characterized. In addition, two different MnP isoenzymes with the same molecular mass (47 kDa) and N‐linked carbohydrate content (4%) and different p__I__ values (3.35 and 3.45) were characterized. Both enzymes showed good stability at 25 °C and over a wide range of pH. Both laccases oxidize ABTS (2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulfonic acid) more efficiently than 2,6‐dimethoxyphenol (DMP) with similar efficiency values (K~cat~/K~m~) while the MnP I, the major peroxidase isoenzyme in the studied conditions, oxidizes the Mn^2+^ and Mn‐mediated activity on DMP more efficiently than MnP II. Copyright © 2006 Society of Chemical Industry