Improved Saccharification Efficiency by Inhibiting a Xylosyltransferase

Full Description

Pamela Ronald and researchers at the Joint BioEnergy Institute (JBEI) have identified a glycosyltransferase encoded by a rice gene that is critical for xylose biosynthesis in plant cell walls. Inhibiting the expression of the gene, Os02g22380, in plants reduces the plants’ lignin content, thus reducing recalcitrance of their cell walls and increasing the amount of soluble sugar that can be extracted from them. The technology is applicable to wheat, rice, corn, switchgrass, sorghum, millet, miscanthus, sugarcane, barley, turfgrass, hemp, bamboo and Bracypodium.

Mutant rice plants based on this finding demonstrated reduced height with leaves deficient in xylose, as well as ferulic acid and coumaric acid – acids linked with the inhibition of microbes’ ability to covert sugars to fuels. In addition, using a promoter to limit the action of this gene to non-vascular tissue improves plant height. For more details, see the publication linked below.

The Joint BioEnergy Institute (JBEI, www.jbei.org) is a scientific partnership led by the Lawrence Berkeley National Laboratory and including the Sandia National Laboratories, the University of California campuses of Berkeley and Davis, the Carnegie Institution for Science and the Lawrence Livermore National Laboratory. JBEI’s primary scientific mission is to advance the development of the next generation of biofuels.

Applications

• Biofuel production
  

Features/Benefits

• Pathway to more efficient saccharification in bioenergy plants
• Increases soluble sugar extraction compared to wild type plants
  

Patent Status

State Of Development

The technology has been tested in rice plants, which demonstrated leaves deficient in xylose, ferulic acid and coumaric acid. Specifically, cell wall extracts given a hot water pre-treatment exhibit a 62% increase in the total sugars released in an enzyme mixture that contains cellulase, α-mannosidase, and hemicellulases. Phenolic composition indicates a strong decrease in ferulic acid (59%) along with a decrease in coumaric acid (44%), which are downstream inhibitors. For more details, see the publication linked below.

Related Materials

• Chiniquy, D., Sharma, V., Schultink, A., Baidoo, E.E.,Rautengarten, C., Cheng, K., Carroll, A., Ulvskov, P., Harholt, J., Keasling, J. D., Pauly, M., Scheller, H.V., Ronald, P.C. XAX1 from glycosyltransferase family 61 mediates xylosyltransfer to rice xylan. PNAS, Vol. 109, No. 42, 17117-17122, October 16, 2012. - 10/16/2012