04/22/2009
Alterations in Poplar Lignin Could Enhance Pretreatment Efficiency
The Science
Alterations in lignin content or structure in plant cell walls can have a profound effect on chemical or enzymatic degradability and the efficiency by which certain pretreatment methods remove lignin from polysaccharides. Great Lakes Bioenergy Research Center researchers found that overexpression of a particular gene [ferulate 5-hydroxylase (F5H)] in the lignin biosynthetic pathway of a hybrid poplar created lignin with a structure and composition that can enhance lignin removal from cellulose, while still maintaining normal growth and development. When compared to wild-type poplar, the up-regulated F5H poplar has a much simpler lignin structure that is less branched and more homogeneous in its subunit composition, which makes the lignin easier to separate from cellulose during pretreatment. This and other poplar transgenic materials under investigation by GLBRC researchers have cell walls that release more sugar than wild-type poplar over a range of pretreatment methods. The altered structural features in the transgenic lignin polymer support the contention that there are significant opportunities to improve biomass utilization by exploiting the malleability of plant lignification processes. Ongoing work is examining the effect of ammonia fiber expansion pretreatment on these transgenic poplars.
Principal Investigator
Shawn D. Mansfield
References
Stewart, J. J., T. Akiyama, C. Chapple. J. Ralph, and S. D. Mansfield, 2009. “The Effects on Lignin Structure of Overexpression of Ferulate 5-Hydroxylase in Hybrid Poplar,” Plant Physiology 150(2), 621–35. DOI:10.1104/pp.109.137059.