Comparative hydrolysis, fermentation, and economic information for application of leading pretreatment technologies to corn stover and poplar

BIOT 119

Charles E. Wyman, cewyman@engr.ucr.edu, Chemical and Environmental Engineering, University of California, Riverside, CA 92521, Bin Yang, binyang@cert.ucr.edu, Center for Environmental Research and Technology, University of California, 1084 Columbia Avenue, Riverside, CA 92507, Bruce E. Dale, bdale@egr.msu.edu, Dept of Chemical Engineering and Materials Science, Michigan State University, 2527 EB, East Lansing, MI 48824, Richard Elander, Richard_Elander@nrel.gov, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, CO 80401, Mark Holtzapple, m-holtzapple@tamu.edu, Chemical Engineering Department, Texas A&M University, College Station, TX 77843, Michael R Ladisch, ladisch@purdue.edu, Laboratory of Renewable Resources Engineering Department, Purdue University, Potter Engineering Center, 500 Central Drive, West Lafayette, IN 47907-2022, Y. Y. Lee, leeyoon@auburn.edu, Department of Chemical Engineering, Auburn University, 207 Ross Hall, Auburn University, AL 36849, Colin Mitchinson, colin.mitchinson@danisco.com, Genencor International, 925 Page Mill Road, Palo Alto, CA 94304, and John N. Saddler, saddler@interchange.ubc.ca, Dean of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada.
Pretreatment is essential to high yields and low costs for biological processing of cellulosic biomass to fuels and chemicals. A team experienced in biomass hydrolysis formed a Biomass Refining Consortium for Applied Fundamentals and Innovation (CAFI) to develop the first comparative data for the promising pretreatment options of ammonia expansion, aqueous ammonia recycle, controlled pH, dilute acid, flowthrough, lime, and sulfur dioxide steam explosion using shared feedstocks, enzymes, procedures, and analytical methods. Corn stover was initially employed, and material balances were developed. In addition, comparative data were developed on the digestibility of the pretreated solids. The fermentability and conditioning requirements of the pretreated hydrolyzates and solids were also assessed. Finally, material and energy balances were developed based on this data and used to project the impact of each pretreatment on the minimum ethanol selling price. All pretreatments were effective in making cellulose in corn stover accessible to enzymes with high yields, with trends slightly better for high pH technologies. Xylose recovery yields were high for all these pretreatments, although hemicellulase activity was vital to recover the substantial amounts of xylan left in the residual solids for pretreatments at high pH. However, yields were much more variable for applications of the same technologies to poplar wood, and significant performance differences were observed among these pretreatments for the same poplar variety from different locations. Overall, these results show the importance of linking selection of pretreatment technology with feedstock choice.
 

Emerging Technologies: Bioenergy
8:00 AM-11:00 AM, Tuesday, August 21, 2007 BCEC -- 109A, Oral

Division of Biochemical Technology

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007