DDGS (distiller's dried grains with solubles) is a major co-product in dry-grind ethanol production from corn. A recently developed physical process separates DDGS into two value-added components: a fiber-enriched DDGS and a portion that is rich in oil and protein. Electrolyzed water, a new pretreatment catalyst was employed to pretreat fiber-enriched DDGS. Four temperatures (130, 145, 160, and 175 degrees C) and three treatment times (10, 20, and 30 min) were examined in the pretreatment with a solid loading of 20% w/w. Other pretreatment methods, such as diluted sulfuric acid, alkaline solution, and hot water, were also tested for comparison purposes. Fifteen FPU cellulase/g cellulose, 40 units beta-glucosidase/g cellulose, and 50 units xylanase/g dry biomass were used in the enzymatic hydrolysis at 50 degrees C and 10% solid loading. The hydrolyzates were fermented by Clostridium beijerinckii BA 101 at 35 degrees C in an auto-controlled Six-fors fermentor with continuous mixing. The highest sugar yield was achieved when using the acidic electrolyzed water treatment at 175 degrees C for 10 min, with 23.25 g glucose, xylose and arabinose released from 100 g fiber-enriched DDGS. The C beijerinckii fermentation produced 535 g ABE (acetone, butanol, and ethanol) from 100 g dry fiber-enhanced DDGS. This study demonstrated that DDGS pretreated with electrolyzed water and hydrolyzed with commercial enzymes could be used to produce biobutanol without detoxification. (C) 2012 Elsevier Ltd. All rights reserved.