Enrich arabinoxylan in corn fiber for value-added products

Corn fiber is an abundant and low-value byproduct in corn processing, which contains about 70% carbohydrates, including starch, cellulose, and arobinoxylan-rich hemicellulose. The utilization of corn fibers is crucial to the profitability and sustainability of a commercial corn processing operation. In this study, a two-step process was proposed and tested for the purpose of utilizing the C6 components for production of bio-ethanol and the C5 component for production of value-added products. Wet milling corn fibers were first pretreated with hot water at 121°C for one hour followed by a glucoamylase hydrolysis to remove starch. The remaining solid was subjected to a second pretreatment with hot water at 140-170°C followed by an enzymatic hydrolysis to further separate C6 and C5 components. After the second pretreatment, the enzyme digestibility of cellulose was much better than that of arabinoxylan. As a result, up to 90% arabinoxylan in corn fibers was retained in solid after an enzyme hydrolysis, while most of C6 components were removed. The two-step fractionation process effectively enriched arabinoxylan. This concept could be used for production of biofuel and XOS/soluble dietary fiber from corn fibers, or for producing ethanol and value-added products from other biomass.