Abstract

Xylan is one of the most abundant polymers on the planet. It is the major non-cellulosic polysaccharide in angiosperms, and it could provide more than a third of the sugars for lignocellulosic biofuels. Unlike cellulose, which is composed of easily fermented hexoses, xylan consists of a pentose backbone, with uronic acid and pentose branches, making it difficult to breakdown and ferment. In addition, the xylan coats the cellulose fibrils, hindering the activity of cellulases. Therefore, xylan is currently considered to be an obstruction to lignocellulosic biofuel production. The work I will describe here identified the genes responsible for xylan branch addition in Arabidopsis. We generated plants with unbranched xylan, and tested the effects of an altered cell wall structure on plant growth. The simplified xylan proved to be more easily extractable from the cell wall, and required fewer enzymes to hydrolyse it to monosaccharides. This may have implications for the production costs of lignocellulosic biofuels.