Only C-2 specific glucose oxidase activity is expressed in ligninolytic cultures of the white rot fungus Phanerochaete chrysosporium

Abstract

Two d-glucose-oxidizing enzymes, glucose 1-oxidase (G1O) and pyranose 2-oxidase (P2O, glucose 2-oxidase), have been proposed to play an important role in the ligninolytic system of the white rot fungus Phanerochaete chrysosporium by producing hydrogen peroxide. The possible simultaneous expression and metabolic cooperation of the two oxidases was studied in strains ME-446 (reported as G1O positive) and K-3 (P2O positive) grown in liquid media and under near natural conditions on birch wood blocks. The presence of G1O and P2O in extracts from mycelia and decayed wood was determined by chromatographic, electrophoretic, and immunological methods. Attempts to separate these enzymes and to detect G1O and its reaction product, d-glucono-1,5-lactone, failed. Evidence was obtained only for P2O expression in both strains. Accordingly, P2O, rather than G1O, represents a major source of sugar-derived H₂O₂ under the culture conditions used.