A laboratory horizontal bioreactor was designed for cellulase and hemicellulase production by the thermophilic fungus Thermoascus aurantiacus grown in solid-state fermentation. The bioreactor was operated at 49 degrees C using wheat straw as carbon source, at 75% moisture content. High levels of cellulolytic and hemicellulolytic activities were obtained. The overall performance of the bioreactor was promising for further investigation.