Regulation of Cellulolytic Activity in the White-Rot Fungus Ischnoderma Resinosum

ABSTRACT

The white-rot fungus Ischnoderma resinosum, which is capable of selective removal of lignin from wood, was grown on soluble media in stationary submerged cultures to investigate the effects of various carbohydrates on cellulolytic activity. The activities of extracellular cellulases (filter paper activity and carboxymethyl cellulase) were higher in cultures grown on carboxymethyl cellulose than in those grown on xylan or glucose. Carboxymethyl cellulase was induced in succinate-grown cultures after the addition of cellobiose or carboxymethyl cellulose; β-glucosidase was induced by cellobiose. Supplemental xylose, arabinose, fucose, glucuronic acid, and several other carbohydrates were catabolite repressors of cellulase activity.

Key Words:

• catabolite repression
• cellulose
• β-glucosidase
• wood decay