A newly isolated thermophilic fungal strain from Tunisian soil samples was identified as Talaromyces thermophilus and was selected for its ability to produce extracellular hemicellulases when grown on various lignocellulosic substrates. Following the optimization of carbon source, nitrogen source, and initial pH of the growth medium in submerged liquid cultures, yields as high as 10.00 +/- 0.15 and 0.21 +/- 0.02 U/ml were obtained for xylanase and beta-xylosidase, respectively. In fact, wheat bran was found to be a good inducer of hemicellulase enzymes, mainly beta-xylosidase. The optimal temperature and pH of the xylanase activity were 75A degrees C and 8.0, respectively. This enzyme exhibited a remarkable stability and retained 100% of its original activity at 50A degrees C for 7 days at pH 7.0-8.0. The half-lives of the enzyme were 4 h at 80A degrees C, 2 h at 90A degrees C, and 1 h at 100A degrees C. T. thermophilus could therefore be considered as a satisfactory and promising producer of thermostable xylanases. Crude enzyme of T. thermophilus rich in xylanase and beta-xylosidase was established for the hydrolysis of lignocellulosic materials as wheat bran.