Monday, May 4, 2009 - 8:30 AM
3-02
Glucose and xylose yields from switchgrass for ammonia fiber expansion, ammonia recycle percolation, dilute sulfuric acid, hot water, lime, and sulfur dioxide pretreatments followed by enzymatic hydrolysis
Charles Wyman, University of California, Center for Environmental Research and Technology, 1084 Columbia Avenue, Riverside, CA 92507, Bruce E. Dale, Department of Chemical Engineering and Material Science, Michigan State University, 2527 Engineering building, E. Lansing, MI 48824, Richard T. Elander, National Renewable Energy Laboratory, 1617 Cole. Blvd MS 3511, Golden, CO 80401, Mark T. Holtzapple, Chemical Engineering, Texas A&M University, 3122 TAMU, College Station, TX 77843-3122, Michael R. Ladisch, Lorre, Purdue University, West Lafayette, 57866, Y. Y. Lee, Department of Chemical Engineering, Auburn University, 207 Ross Hall, Department of Chemical Engineering, Auburn, AL 36849, Colin Mitchinson, Genencor, A Danisco Division, 925 Page Mill Road, Palo Alto, CA 94304, and Steve Thomas, Ceres, Inc., 1535 Rancho Conejo Blvd, Thousand Oaks, CA 91320.
Switchgrass promises to become a major resource for making fuels and chemicals by cellulose conversion technologies. However, it must be pretreated to realize reasonable yields of sugars by enzymatic hydrolysis, but pretreatment is expensive and strongly influences cost and performance of other operations. The Biomass Refining Consortium for Applied Fundamentals and Innovation (CAFI) was formed in 2000 to develop the first comparative data of sugar yields from leading pretreatment operations followed by enzymatic hydrolysis of resulting solids. The CAFI Team achieved high sugar yields from corn stover for all pretreatments but found much greater variations in performance for poplar wood with changes in pretreatment technologies and biomass source. In this project, pretreatment by ammonia fiber expansion (AFEX), ammonia recycle percolation (ARP), dilute acid, hot water, lime, and sulfur dioxide steam explosion were applied to shared sources of switchgrass, and the same enzymes, experimental protocols, and material balance approaches were employed by all the members of the team. Three types of switchgrass, Alamo, Shawnee, and Dacotah, were evaluated from different locations and harvest times to determine whether these factors influence glucose and xylose yields from the combined operations of pretreatment and enzymatic hydrolysis. Comparisons will be reported for sugar yields from pretreatment alone (Stage 1), enzymatic hydrolysis (Stage 2), and the two combined over a range of enzyme mass loadings and formulations for each pretreatment approach. These results should help select pretreatment technologies for commercial operations and define new directions to improve plants, enzymes, and pretreatment technologies.