Cell wall lignin programme: Manipulating lignin to improve biofuel conversion of plant biomass

改善用于生物燃料生产的植物材料的一个显而易见的方法是控制植物细胞壁的结构，因为细胞壁中的抗性聚合物阻止微生物酶将植物材料降解为单糖和乙醇。在这方面，最重要的细胞壁聚合物之一是木质素。我们已经对木质素是如何产生的以及如何在木本植物中操纵木质素有了相当多的了解。然而，大部分可用于生产能源的植物生物量来自禾草，因此需要更多的研究来使我们能够操纵这些类型的植物中的木质素。大麦是可能用于能源应用的牧草（如芒草）的一个很好的模型，大麦比大多数其他牧草有更多的研究工具。大麦和小麦秸秆废料也可能是生产生物燃料的有用资源，而且大麦的基因发现通常可以转移到小麦上。该项目旨在确定木质素含量和结构如何影响(1)大麦秸秆可以释放的糖的量；(2)这些糖转化为生物燃料的效率如何；(3)大麦秸秆燃烧所能释放的能量。这将表明如何最好地操纵聚合物，使其更容易从植物生物质中生产生物燃料。我们还旨在确定木质素生物合成基因是否对大麦抗病或茎秆强度有重要影响，以便我们确定如何在保持植物健康的同时操纵木质素。我们分离的基因和遗传标记可直接用于能源作物改良育种计划。因为我们将研究许多不同的大麦品种，我们也将能够确定哪些品种最适合生物燃料生产，哪些品种最适合燃烧以获取热量和能源。

An obvious way of improving plant materials for biofuel production would be to manipulate the structure of plant cell walls, since it is resistant polymers in these walls that prevent microbial enzymes from degrading the plant material into simple sugars and ethanol. One of the most important cell wall polymers in this respect is lignin. We already know quite a lot about how lignin is made and how it can be manipulated in woody plants. However much of the plant biomass that could be used to produce energy comes from grasses, and more research is therefore needed to enable us to manipulate lignin in these types of plant. Barley is a good model for the grasses that might be grown for energy applications (e.g. Miscanthus), and there are more research tools available for barley than for most other grasses. Barley and wheat straw waste could also be useful resources for biofuel production, and genetic discoveries in barley are usually transferable to wheat. This project aims to determine how lignin content and structure influence (1) the amount of sugars that can be released from barley straw; (2) how efficiently these sugars can be converted into biofuels; and (3) the amount of energy that can be released from barley straw by burning. This will indicate how the polymer can best be manipulated to make it easier to produce biofuels from plant biomass. We also aim to determine whether any lignin biosynthesis genes are important for barley disease resistance or stem strength, so that we can determine how to manipulate lignin while keeping plants healthy. The genes and genetic markers that we isolate can be used directly in energy crop improvement breeding programmes. Because we will be looking at a lot of different barley varieties, we will also be able to identify which current varieties are best for biofuel production and for burning for heat and energy.