A process for obtaining a product 
sugar stream from cellulosic 
biomass is disclosed. In one process, the cellulosic 
biomass is pretreated at a pH between about 0.4 to 2.0 by adding one or more than one acid to produce a pretreated cellulosic 
biomass comprising 
acetic acid. One or more than one base is then added to the pretreated cellulosic biomass to adjust the pretreated cellulosic biomass to a pH of about 4.0 to about 6.0 to produce a neutralized cellulosic biomass comprising inorganic salt and 
acetate salt. The neutralized biomass is then hydrolyzed by 
cellulase enzymes to produce a crude 
sugar stream. 
Insoluble residue is separated from the crude 
sugar stream and the resulting clarified sugar stream is treated using 
ion exclusion 
chromatography at about pH 5.0 to about 10.0 to produce one or more 
raffinate streams and a product stream. The 
raffinate stream comprises 
inorganic salts and acetate salts, and the product stream comprises sugar. The product stream may then be fermented or otherwise further processed. In an alternate process, a product sugar stream is obtained from a crude sugar stream that is produced from conversion of cellulosic biomass to sugar. The cellulosic biomass may be produced using any suitable method. In this process the crude sugar stream is treated using 
ion exclusion 
chromatography at about pH 5.0 to about 10.0 to produce one or more than one 
raffinate stream comprising 
sulfate and acetate salts, and a product stream comprising sugar, and the product sugar stream is obtained.