Expression of Pleurotus eryngii aryl-alcohol oxidase in Aspergillus nidulans: purification and characterization of the recombinant enzyme.

Aryl-alcohol oxidase (AAO) is an extracellular flavoenzyme involved in lignin biodegradation by some white-rot fungi. The enzyme catalyzes the extracellular oxidation of aromatic alcohols to the corresponding aldehydes. The electron acceptor is molecular oxygen yielding H(2)O(2) as the product. Herein we describe, for the first time, the expression of AAO from Pleurotus eryngii in the ascomycete Aspergillus nidulans. The activity of the recombinant enzyme in A. nidulans cultures is much higher than found in the extracellular fluid of P. eryngii. The recombinant enzyme showed the same molecular mass, pI and catalytic properties as that of the mature protein secreted by P. eryngii. The enzymic properties are also similar to those reported from other Pleurotus and Bjerkandera species.