Melanocarpus albomyces IIS 68 synthesizes xylanase, ,&xylosidase and xylan debranching enzymes, namely, acetyl esterase, a+arabinofuranosidase and a-o-giucuronidase, when grown on various substrates. All five
enzymes were found to be inducible. Wheat straw was found to be the best carbon source for production of extracellular xylanase (172 H/ml) and the maximum number of xylanase isoenxymes. Out of the seven xylanase isoenxymes, xylanase Ic was found to be constitutive whereas the other six xylanases, namely, Ia, Ib, IIa, IIb,
IIc and III, exhibited more speck! inducibillty, the magnitude of which depended on the nature of the inducer. The best inducer for bxylosidase and acetyl esterase synthesis by washed mycella was wheat straw whereas arabinose and birchwood xylan brought about the maximum induction of a+arabinofuranosidase and U-D- glucuronidase, respectively. In general, complex substrates were more effective inducers for xylanolytic enzymes than simple sugars.