Aromatic feedstock chemicals from degradation of lignin

当今社会面临的最大问题之一是我们对日益减少的化石燃料的依赖，以及使用化石燃料的发电站、汽车运输和家庭供暖对全球变暖的贡献。石油不仅用于制备燃料，而且炼油的重要副产品是生产化学和药物合成的原料。在50-100年的时间里，所有这些化学品都需要从可再生的非石油资源中生产，但目前我们有非常有限的方法来做到这一点，因此需要在相对较短的时间内开发许多新技术。在植物细胞壁中发现的植物木质纤维素的碳含量代表了丰富的可再生碳源。木质纤维素的一种成分是一种叫做木质素的芳香族聚合物，它将纤维素细胞壁结合在一起。木质素很难分解，所以目前木质纤维素的分解是通过“预处理”步骤进行的，通常包括用酸和蒸汽加热到200 ℃，这会消耗大量能源。因此，如果我们能够利用自然界来分解木质素，我们将提高木质纤维素的分解效率，并释放有用的芳香副产物。我们最近开发了一种新的方法来鉴定能够分解木质素的细菌菌株，我们已经发现了几种能够做到这一点的细菌菌株。我们将从这些菌株中分离木质素降解酶，并利用分子遗传学方法大量生产这些酶，为进一步研究奠定基础。然后，我们将使用这些菌株，试图从木质纤维素的分解产生有用的芳香化学品。一个例子是香草醛，它用于香草冰淇淋等产品中的食品调味剂;其他例子是用于塑料制造的苯酚。

One of the biggest problems facing society today is our dependence on dwindling fossil fuels, and the contribution to global warming of power stations, car transport and domestic heating that make use of fossil fuels. Not only is oil used to prepare fuel, but also an essential by-product of oil refining is the production of raw materials for chemical and pharmaceutical synthesis. In 50-100 years time, all of these chemicals will need to be produced from renewable, non-petroleum sources, but at present we have very limited methods to do this, so a lot of new technology needs to be developed in a relatively short space of time. The carbon content of plant lignocellulose, found in plant cell walls, represents an abundant source of renewable carbon. One component of lignocellulose is an aromatic polymer called lignin, that binds the cellulose cell walls together. Lignin is very hard to break down, so at present lignocellulose is broken down via a 'pre-treatment' step, usually involving heating with acid and steam to 200 oC, which consumes a lot of energy. Therefore, if we could use Nature to break down the lignin, we would improve the efficiency of lignocellulose breakdown, and liberate useful aromatic by-products. We have recently developed a new method for identifying strains of bacteria that are able to break down lignin, and we have already found several strains of bacteria that are able to do this. We will isolate the lignin-degrading enzymes from these strains, and use molecular genetics to produce large quantities of these enzymes for further studies. We will then use these strains to try to produce useful aromatic chemicals from breakdown of lignocellulose. One example is vanillin, which is used for food flavouring in products such as vanilla ice cream; other examples are phenols that are used in the manufacture of plastics.