Monday, May 4, 2009
9-62
Ethanol from xylose using an immobilized enzyme recirculation reactor
Christopher C. Beatty1, Stephen J. Potochnik1, Cassie Khavari1, and Vincent T. Remcho2. (1) Trillium FiberFuels, Inc, 33898 SE Eastgate Circle, Corvallis, OR 97333, (2) Chemistry, Oregon State University, 236 Gilbert Hall, Oregon State University, Corvallis, OR 97331
Xylose from straw hydrolyzate and other biomass sources can be converted to ethanol at high yield with a system that recirculates the fermentation broth through a parallel reactor containing immobilized xylose isomerase (EC 5.3.1.5). There are numerous process flow options for this flexible process, but we have chosen to validate the concept on a dedicated xylose fermentation system that occurs after a conventional C-6 Simultaneous Saccharification and Fermentation plus solid-liquid separation. Within the xylose system, several conventional yeasts including Schizosaccharomyces pombe are able to ferment the xylulose product created by the isomerization reaction. This yeast requires no genetic modification and the yield, rate, and co-product formation are very good. The engineering controls for the system to ensure optimal performance of the enzyme are straightforward. Economic performance of the system is heavily dependent on the productivity of the enzyme which has been shown to be greater than 3000 kilograms of product per kilogram of enzyme with straw hydrolyzate. Scale-up to a 200 liter system is currently underway.
Web Page: www.trilliumfiberfuels.com