Faced with an escalating demand for fuel ethanol, researchers and ethanol industries are searching for ways to enhance ethanol yield by incorporating cellulosic ethanol technologies into current ethanol processes. Distiller's grains are a major co-product of dry grind ethanol industry that is rich, not only in proteins, but also in unutilized polymeric sugars, such as cellulose, xylan and residual starch. Efforts are underway to utilize and process co-products from dry grind ethanol processes for additional fermentable sugars and ethanol, while preserving the value of the residue as an animal feed. Efficient digestibility of distiller's grains was demonstrated from a laboratory scale hydrolysis of distiller's dried grains, with solubles (DDGS) pretreated by aqueous hot liquid water. This resulted in 92% conversion of total glucan to glucose within 24 hours by 15 FPU of cellulase per gram of glucan. Including a complete compositional analysis of distiller's grains, its digestibility and fermentability. This paper reports a model of a proposed dry grind ethanol process that integrates cellulosic ethanol technologies for enhanced ethanol yield through use of distiller's grains. Theoretical ethanol yields, compositions of resulting co-products, and challenges in implementing a modified dry grind process are discussed.

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