In this study, the effect of ethylenediamine (EDA) on enzymatic hydrolysis with different cellulosic substrates and the approaches to reduce sugar loss in enzymatic hydrolysis were investigated. During enzymatic hydrolysis, xylose yield reduced 21.2%, 18.1% and 13.0% with 7.5 mL/L EDA for AFEX pretreated corn stover (CS), washed EDA pretreated CS and CS cellulose. FTIR and GPC analysis demonstrated EDA reacted with sugar and produced high molecular weight (MW) compounds. EDA was prone to react with xylose other than glucose. H2O2 and Na2SO3 cannot prevent sugar loss in glucose/xylose-EDA mixture, although they inhibited the browning and high MW compounds formation. By decreasing temperature to 30 degrees C, the loss of xylose yield reduced to only 3.8%, 3.6% and 4.2% with 7.5 mL/L EDA in the enzymatic hydrolysis of AFEX pretreated CS, washed EDA pretreated CS and CS cellulose. (C) 2016 Elsevier Ltd. All rights reserved.