Most mass in the plant cell wall is in the form of polysaccharides- cellulose and hemicellulose. These carbohydrates can be fermented and converted to biofuels. Depending on the feedstock, the plant cell wall consists of about 40% cellulose, while another third is hemicelluloses (i.e arabinoxylan, glucuronoxylan, mixed linkage glucan, xyloglucan and/or glucomannan), and the remainder is lignin and other components. Lignocellulosic biomass has long been recognised as a potential low-cost source of sugars for fermentation to fuel and can be converted to mixed sugar solutions by the use of hydrolytic enzymes (saccharification). However, plant biomass has evolved effective mechanisms for resisting assault on its structural sugars from the microbial and animal kingdoms. This property underlies the natural recalcitrance, creating technical barriers to the cost-effective transformation of the lignocellulosic biomass to fermentation sugars. The composition of the mixed sugar and oligosaccharide solution and polysaccharide residues after saccharification varies according to plant biomass and the hydrolytic enzyme specificity, for example. Hence, it becomes clear that we need to develop accurate, robust and high-throughput methods for the analysis of the plant cell wall polysaccharides and the hydrolytic enzymes.
The Cell Wall Sugars programme is aiming in understanding how structural sugars are arranged in the cell walls and focuses on improving plants for enhanced biofuel production and also matching them with the most effective hydrolytic enzymes for improved saccharification. The Cell Wall Sugars programme aims are:
• Understanding the plant cell wall polysaccharide synthesis by identifyimg genes that controll that process.
• Understanding how cell wall sugar structures inhibit saccharificationby hydrolytic enzymes and therefore optimising polysaccharide synthesis and structure for more effective enzyme digestion.
• Discovering novel enzymes which allow release of sugars from cell wall components that are currently indigestible.
• Developing tools to analyse the plant cell wall polysaccharide structure and to characterise novel saccharification enzymes.
The Cell Wall sugars programme lead by the University of Cambridge (leading Primary Investigator Professor Paul Dupree) is utilising the following resources and technologies for the successful improvement of plants for biofuel production:
• Cell wall sugar analysis, metabolomics, proteomics and bioinformatics.
• Discovering genes controlling plant cell wall polysaccharide synthesis.
• Polysaccharide hydrolase enzyme discovery.
• Industrial partners with biofuel and bioinformatics experience, and unique enzyme rescourses.
The programme members include:
• University of Cambridge: Professor Paul Dupree
Dr Elaine Stephens
Dr Kathryn Lilley
Dr Jules Griffin
Dr John Dennis
• University of Newcastle: Dr David Bolam
• Novozymes: Dr Katja Salomon-Johanssen
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