Monday, April 19, 2010
2-17

Plant cell-wall recalcitrance and saccharification efficiency of lowland switchgrass variety Alamo

Hui Shen1, Chunxiang Fu2, Xirong Xiao2, Tui Ray1, Yuhong Tang1, Zengyu Wang2, Fang Chen1, and Richard A. Dixon1. (1) Plant Biology Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401, (2) Forage Improvement Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401

The switchgrass cultivar Alamo has been selected as a biofuel grass for bioethanol production in BESC (the BioEnergy Science Center, US Department of Energy). The recalcitrance of lignified cell-walls has been considered a major obstacle for cellulosic ethanol production from switchgrass biomass. Plant cell-wall recalcitrance and saccharification efficiency  were studied in the lowland switchgrass variety Alamo. First, a comprehensive study was undertaken of cell-wall structure, soluble and wall-bound phenolic content and composition, lignin content and composition, and lignin biosynthetic gene expression in developing stems of greenhouse-grown plants harvested at different developmental stages.  The lignification pathway in developing stems is under complex spatial and temporal control. The major biochemical parameters that may affect the cell wall recalcitrance properties of Alamo were determined to include lignin content, monolignol unit composition, and wall-bound phenolic acid content and composition. Finally, the relationships of these biochemical parameters to saccharification efficiency were determined for field-grown material. The lignin and ester-linked p-hydroxybenzoic acid contents showed strong negative correlations with saccharification efficiency, but ester-linked ferulic acid positively correlated with saccharification efficiency. In summary, our data provide a basis for directing future studies to modify cell wall recalcitrance for improved biomass deconstruction efficiency.


Web Page: www.springerlink.com/content/q60225850r41p674/?p=2b7dfba4b5134997b90c9825f740d24d&pi=7