One of the important steps in the application of biomass to producing sugars, which can be converted into bio-ethanol and other valuable chemicals by fermentation, is to hydrolyze the biomass components by sulfuric acid. It was reported that such a hydrolysis entailed the generation of acetic acid, which has been recognized as a key impurity to be surely removed from the biomass hydrolyzate for ensuring high fermentability of the hydrolyzed sugars. Regarding such a removal task, there has been a previous application of a simulated moving bed (SMB) process based on the Dowex99 adsorbent, whose performance, however, was limited by low selectivity between acetic acid and sugars. To overcome such a limitation, another adsorbent alternative to Dowex99 was searched in this study. It was found that Amberchrom-CG161C allowed higher selectivity between acetic acid and sugars than Dowex99. To investigate the relative superiority of Amberchrom-CG161C over Dowex99 as the adsorbent of an SMB process for removing acetic acid from the biomass hydrolyzate, the two SMB processes based on Amberchrom-CG161C and Dowex99 were optimized using the SMB optimization tool based on standing wave design (SWD) method. The optimization results revealed that the Amberchrom-CG161C SMB outperformed the Dowex99 SMB by a wide margin. (C) 2011 Elsevier Ltd. All rights reserved.