The use of fossil fuels in the energy and chemical industries is no longer tenable; they represent a finite resource and their use results in carbon dioxide emissions, which is a major cause of global warming. There is, therefore, an urgent need to find alternative sources of liquid fuels that are renewable and do not have an adverse effect on the environment. Lignocellulosic biomass is a promising substrate for biofuel production as it is not a food source, is more abundant than starch, and its use is carbon dioxide neutral. A significant limitation in the use of lignocellulosic biomass in the biofuel industry is its recalcitrance to enzyme attack. Thus, cellulose, the major polysaccharide in lignocellulosic biomass, is chemically simple but its highly crystalline structure makes it inaccessible to enzymes that act as hydrolases. Recent studies, however, have identified novel enzymes that could improve the efficiency of plant cell wall deconstruction. Thus, several reports have shown that oxidases cleave bonds in crystalline regions of cellulose, leading to increased access to hydrolase attack. Significant advances have also been made in the degradation of xylan, the major matrix polysaccharide in lignocellulosic biomass. It was widely believed that degradation of the main chain of xylan required the removal of side chains prior to attack by xylanases. It is now apparent that a cohort of xylanases not only accommodate side chains, but actually display an absolute requirement for these decorations. We have also shown that it is possible to introduce novel functionalities into the active site of biotechnologically significant arabinofuranosidases that assist in removing the side chains from xylan. The generation of such multifunctional enzymes has the potential to simplify the biocatalysts required to deconstruct plant cell walls, and thus increase the economic potential of lignocellulosic biomass as a substrate for the biofuel industry. In this project we will explore the mechanism by which cellulose oxidases, arabinoxylanases and multifunctional arabinofuranosidase/xylanases recognize their target substrates. The data will provide a blueprint for further enhancing the efficiency of the plant cell wall degrading catalytic toolbox.