Regional Competitive Grants

Project Title: Comparative Genomics Guided Genetic Modification of Switchgrass Cell Wall for Improved Lignin Characteristics and Increased Cellulose Availability

Principal Investigators and affiliations:

• PI: Neal Stewart (University of Tennessee, Department of Plant Sciences)
• Co-PI: Nicole Labbe (University of Tennessee, Forest Products Center)
• Co-PI: John Collier (Florida State University, Department of Chemical and Biomedical Engineering 
• Co-PI: Joe Bozell (University of Tennessee, Forest Products Center)
• Co-PI: Joshua Yuan (University of Tennessee, Department of Plant Sciences)
• Co-PI: Sarwan Dhir (Fort Valley State University, Plant Science Center for Biotechnology)   

Start Date: 9/1/2007      End Date: 8/31/2009

Project Abstract:

One of the major limiting factors for efficient conversion of lignocellulose into sugar for ethanol production is the interference of biomass processing by lignin. Previous research has proven that altering lignin content and composition by genetic modification can improve both cellulose production and the efficiency of converting cellulose to sugars for ethanol production. However, limited research has been carried out to study the effects of lignin modification in grass species, from which several bioenergy feedstocks will be developed. We propose a comparative genomics guided approach to study the effects of reducing lignin production in both rice and switchgrass. As a grass model, rice has ample genome information to enable wide-reaching research on lignin modification. Rice mutants and transgenic lines for key lignin biosynthesis genes will be analyzed for cell wall integrity, cellulose production and digestion to sugars, and lignin reactivity. Results in rice will be translated to produce altered lignin profiles in switchgrass as a feedstock. Homology cloning and downregulation of key switchgrass lignin pathway genes will be accomplished and the resulting cell walls will be extensively characterized by the multidisciplinary and multi-institutional research team from two perspectives. Firstly, the effects on biomass processing efficiency will be studied, and secondly, the impact of genetic/structural modification on utility of lignin as a biorefinery process stream will be investigated by examining its reactivity in focused oxidative conversion processes. The proposed research represents first attempts at modifying lignin in switchgrass and one of few studies to combine structure modification with bioprocess/biorefinery steam research.

Reports and Publications:

Quarter 1 - 2009
Quarter 2 - 2009