This work shows both cellulases and hemicellulases are inhibited and deactivated by water-soluble and acetone extracted phenolics from sugarcane bagasse pretreated at 10% (w/v) for 30 min in liquid hot water at 180 or 200 degrees C. The dissolved phenolics in vacuum filtrate increased from 1.4 to 2.4 g/L as temperature increased from 180 to 200 degrees C. The suppression of cellulose and hemicellulose hydrolysis by phenolics is dominated by deactivation of the beta-glucosidase or beta-xylosidase components of cellulase and hemicellulase enzyme by acetone extract at 0.2-0.65 mg phenolics/mg enzyme protein and deactivation of cellulases and hemicellulases by the water soluble components in vacuum filtrate at 0.05-2 mg/mg. Inhibition was a function of the type of enzyme and the manner in which the phenolics were extracted from the bagasse. (C) 2015 Elsevier Ltd. All rights reserved.