Among the polymeric substrates studied for the production of xylanase by Verticillium tricorpus, xylan was found to be the best inducer of xylanase. beta-Glucosidase and glucanase were other cellulytic enzymes which were synthesized but at low activities. The initial production of high molecular weight products during xylan degradation indicated that the xylanase behaved as a typical endoenzyme. Verticillium tricorpus produced at least three polysaccharolytic enzymes in the xylan medium. Copyright (C) 1996 Elsevier Science Ltd.