Sustainable Bioenergy Centre: Cell wall sugars programme

为了实现从植物生物质（木质纤维素）生产生物燃料的目标，植物细胞壁可以通过产生单糖的水解酶的混合物降解（糖化）。在添加酶混合物之前，预处理生物质原料以增加纤维素和半纤维素的酶可及性。然后，释放出的糖被工业发酵以产生生物燃料，如乙醇和丁醇。木质纤维素生物燃料技术的可行性将取决于最大限度地提高生物质中的可发酵糖，并最大限度地降低加工成本。目前，很难使用富含戊糖的半纤维素木聚糖组分，该组分占大多数原料如草和木材的20- 30%。这种木聚糖阻碍酶接近纤维素，部分是通过与木质素的连接。其中一个主要问题是它是一种支链聚合物，很难用酶分解。分解半纤维素的酸处理可产生抑制剂，其阻止有效的微生物发酵并降低糖的产率。该计划旨在更好地了解半纤维素合成的遗传控制，特别是生物质的支链木聚糖组分，以及木聚糖支链对酶可及性的影响。它将发展植物多糖合成机制的综合特性，以及合成酶如何在蛋白质复合物中共同工作。该计划还将发现和开发有效的酶，将这种成分分解为单糖。该计划将提供高通量，详细，定量分析生物质半纤维素和分解它们的酶活性的技术。基于这些知识，将提出植物育种或修饰以及水解酶选择的策略，以降低生物质的支链木聚糖组分的使用成本，并释放纤维素用于糖化。剑桥研究细胞壁合成和开发多糖和水解酶分析技术的计划得到了纽卡斯尔大学酶发现的支持，大卫博兰博士和哈利吉尔伯特教授的合作。壳牌全球解决方案是该计划的合作伙伴，提供重要的工业视角和生物信息支持。将提供用于方法开发和细胞壁多糖分析的其他酶，并与世界酶生产领导者Novozymes合作进行研究。

To achieve the goal of producing biofuel from plant biomass (lignocellulose), the plant cell wall can be degraded by a cocktail of hydrolase enzymes that generate monosaccharide sugars (saccharification). Biomass feedstocks are pretreated to increase enzyme accessibility of the cellulose and hemicelluloses prior to addition of the enzyme cocktails. The released sugars are then industrially fermented to generate biofuels such as ethanol and butanol. The viability of lignocellulosic biofuel technology will depend on maximising the fermentable sugar from biomass, and minimising the costs of processing. Currently, it is difficult to use the pentose-rich hemicellulose xylan component which constitutes 20- 30% of most feedstocks such as grass and wood. This xylan impedes enzyme access to the cellulose, in part through links with the lignin. One of the main problems is that it is a branched polymer that is difficult to break down with enzymes. Acid treatments to break up the hemicellulose can generate inhibitors that prevent effective microbial fermentation and reduce the yield of sugars. This programme aims to achieve a better understanding of the genetic control of hemicellulose synthesis, especially the branched xylan component of biomass, and the impact of xylan branching on enzyme accessibility. It will develop a comprehensive characterisation of plant polysaccharide synthesis machinery, and how the synthesis enzymes work together in protein complexes. The programme will also discover and characterise effective enzymes that break down this component to monosaccharides. The programme will deliver enabling technologies for high throughput, detailed, quantitative analysis of biomass hemicelluloses and the activity of the enzymes that break them down. Based on this knowledge, strategies of plant breeding or modification, and also of hydrolytic enzyme selection, will be proposed in order to reduce the costs of use of the branched xylan component of biomass, and to release the cellulose for saccharification. The programme in Cambridge to study cell wall synthesis and to develop the polysaccharide and hydrolase profiling technologies is supported by enzyme discovery in the University of Newcastle, with Dr David Bolam and collaboration with Professor Harry Gilbert. Shell Global Solutions are collaborators in the programme, providing an important industrial perspective and bioinformatic support. Additional enzymes for method development and for analysis of cell wall polysaccharides will be provided and studied in collaboration with Novozymes, the world leader in enzyme production.