Sunday, May 4, 2008 - 4:00 PM
1-04
Switchgrass, lignin, enzymes and ethanol
Gautam Sarath1, Christian Tobias2, Bruce S. Dien3, Madhavan Soundararajan4, Kenneth P. Vogel1, Robert B. Mitchell1, and Paul Twigg5. (1) Grain, Forage, and Bioenergy Research Unit, USDA-ARS, 314 Biochemistry Hall, UN-L East Campus, Lincoln, NE 68583-0737, (2) Western Regional Research Center, USDA, Agricultural Research Service, 800 Buchanan Street, Albany, CA 94710, (3) National Center for Agricultural Utilization Research, USDA-ARS, Midwest Area, 1815 N. University Street, Peoria, IL 61604, (4) Biochemistry, University of Nebraska, N253 Beadle Center, City Campus, UN-Lincoln, Lincoln, NE 68588-0664, (5) Department of Biology, University of Nebraska, Kearney, Bruner Hall, 905 W. 25th Street, Kearney, NE 68849
Switchgrass populations divergently selected for in-vitro dry matter digestibility (IVDMD) have yielded plants with significant differences in total lignin in stems. These plants constitute a resource to understand exploitable diversity in traits that could improve switchgrass as a biofuel crop. In this study we have used a variety of methods to phenotype select plants from these populations. Carbon-isotope discrimination data revealed a tendency of plants with high lignin to discriminate less than plants with low lignin, suggesting subtle changes in the levels and activities of enzymes involved in lignin biosynthesis. Thioacidolysis of stem tissues indicated that differences in the levels S- and H-lignin and variable incorporation of hG-lignin into cell walls were genotype dependent. The relative contributions of the different lignin-biosynthetic enzymes and isozymes to the observed lignin compositional data appear to be complex. Ethanol yields from SSF of mild pretreated whole biomass did not differ with stem lignin content, suggesting further studies are needed using fractionated stem material. The relationships between lignin, carbon-isotope discrimination ratios, levels and activities of specific lignin-biosynthetic enzymes to ethanol conversion in these plants will be presented.
See more of Advances in Bioenergy Feedstocks and Plant Science
See more of General Submissions
See more of The 30th Symposium on Biotechnology for Fuels and Chemicals (May 4 -- 7, 2008)
See more of General Submissions
See more of The 30th Symposium on Biotechnology for Fuels and Chemicals (May 4 -- 7, 2008)