The biosynthesis of inducible extracellular enzymes is repressed by glucose in most bacteria; however glucose did not repress xylanase biosynthesis in Thermomonospora curvata in the presence of an inducer When xylobiose was added to glucose-grown, exponential phase cells, the rate of glucose uptake decreased, xylobiose was taken up, and xylanase biosynthesis was induced. The ability of this thermophilic actinomycete to resist repression of xylanase biosynthesis would be particularly advantageous in solid waste composting, where pH and temperature are optimal for the activity of this thermostable enzyme. (C) 1997 Elsevier Science Ltd.