Functional Analysis of Genes Involved in Cell Wall Biosynthesis of the Model Species Brachypodium distachyon to Improve Saccharification

Abstract

Members of the grass family are important as resource for the production of first generation bio-ethanol, which is based on the fermentation of starch and sucrose which is obtained from food crops like corn (US), wheat (Europe) or sugarcane (Brazil). If Europe wants to meet the objective of the new directive on the promotion of the use of energy from renewable sources, it will be necessary to make the transition from first to second generation conversion technologies for the production of bio-ethanol. These conversion techniques are based on the use of recalcitrant lignocellulosic biomass as feedstock. The energy contained in lignocellulosic biomass is largely entrapped in the plant cell wall, which is built up of cellulose, hemicellulose and lignin and can make up to 70% of the total plant biomass. To be able to produce ethanol from these rigid cell walls, the cellulose and hemicellulose need to be degraded first into monosaccharides. For the moment, this degradation constitutes a bottleneck in the process. Especially lignin is a disturbing factor. Therefore, an interesting approach to improve lignocellulosic crops is to reduce their lignin content. In this study, we use Brachypodium distachyon as a model to study the effect of up- or down regulation of genes with a key-role in the monolignol biosynthesis pathway on the saccharification efficiency. The general strategy and preliminary results of this study will be discussed.