Two laccase isoenzymes and a peroxidase of a commercial laccase-producing basidiomycete, Trametes sp. Ha1

Three extracellular ligninolytic oxidoreductases that are produced by a commercial laccase-producing Trametes sp. Ha1 were purified and characterized. This fungus showed strong ligninolytic oxidoreductase activity with and without hydrogen peroxide present in the reaction mixture. The oxidoreductase activity was found to be derived from two laccases and a peroxidase. One of the two laccases represents a main component of the commercial laccase preparation from Trametes sp. Ha1. This enzyme had a high thermostability, which makes it attractive for practical applications. The second laccase was induced by the addition of p-xylidine into the culture medium and showed unique characteristics with respect to pI value and substrate specificity. The peroxidase showed wide oxidation activity against aromatic compounds. [Copyright &y& Elsevier]