Tuesday, May 1, 2007 - 8:00 AM

Development of an integrated corn biorefinery concept

Mark H. Emptage, Central Research & Development, DuPont, Experimental Station - E328, Wilmington, DE 19880

As the nation strives to develop alternative energy sources to replace oil, fuel ethanol derived from corn has become the fastest growing agricultural product in the US.  To meet newly legislated renewable fuel requirements, the focus has shifted to creating economical biomass to fuel technologies on a relatively short timetable.  In cooperation with the Department of Energy, DuPont has been working over the past 4 years to develop an economical corn stover to ethanol conversion technology.  The DuPont Integrated Corn BioRefinery (ICBR) concept is based on the guiding principles of a simple, robust, low cost process with a minimum of separation steps, emulating the highly successful dry grind corn to ethanol process.  We have taken a holistic approach, including the use of Life Cycle Analysis to understand the impact on agricultural practices and the environment, as well as economic tradeoffs of various options for feedstock and process.  The result is an integrated process to convert first pass stover residue collected during grain harvesting.  The DuPont ICBR process includes a mild ammonia pretreatment which gives high yields and minimizes production of fermentation inhibitors.  The co-fermentation of the glucose and xylose in the as-produced hydrolysate with a proprietary recombinant Zymomonas mobilis strain has been demonstrated to high ethanol titers.  Our process minimizes the need for non-renewable fuel to sustain the biorefinery through full integration and recycle of heat, water and ammonia.  While further development continues, using this integrated process we have demonstrated the potential to achieve commercially viable rates, yields and titers.