The application of strongly acidic electrolyzed water (SAEW) in a flow-through system for the treatment of recalcitrant corn stover resulted in enhanced hemicellulose degradation at 160 degrees C and 180 degrees C compared to hydrochloric acid treatment under the same pH. Pretreatment conditions were optimized by varying the four main factors: pH, flow rate, temperature, and reaction time. About 96% of the hemicellulose was removed when corn stover was treated at 180 degrees C for 20 min, with SAEW at pH 2.0 and a flow rate of 10 mL/min. The recovery of total monomeric and oligomeric xylose in the liquid fraction reached 93%. Using 30 filter paper units of cellulase per gram of cellulose, a digestibility of 100% was achieved under these conditions. Therefore, flow-through SAEW pretreatment is an efficient way to remove hemicellulose and improve enzymatic digestibility of corn stover. (C) 2011 Elsevier Ltd. All rights reserved.