Synthetic and Mechanistic Studies into Enzymatic Degradation of Waste Plastics

塑料是一种广泛的固体聚合物材料，广泛应用于工业部件和消费品。然而，世界各地的废弃塑料一直在稳步积累，现在人们越来越意识到它们对自然环境和人类健康构成了重大危害。关于这些问题，越来越强调塑料材料的回收（和随后的再使用），或将其转化为可以作为新产品原料的其他材料。已知在生物质分解中催化氧化的一些酶可以转化通常对其他类型的化学反应具有抗性的化合物；因此有人提出能够分解塑料。该项目旨在研究一系列氧化酶的应用，以降解含有化学不反应的C-C、C-H和C-O化学键的塑料，目前尚无可行的后处理方法。因此，研究将涉及塑料小分子模型的化学合成、酶的异种生产、酶与模型分子的测试以及通过一系列分析方法（光谱、电化学和色谱）对酶反应的机理研究。通过使用小模型分子，可以收集详细的化学反应性信息，这将使后续的任何有前途的酶候选物的再工程更合理的方法用于该应用。辅助研究目标包括研究与塑料材料加工相关的候选酶的物理化学性质，例如确定酶对有机溶剂的耐受性及其热稳定性。氧化酶在这方面的应用目前还没有得到充分的探索，而且在很大程度上是以零敲碎打的方式进行的，导致经验观察难以合理化（因此也难以进一步利用）。本研究旨在填补这一知识空白。从战略角度来看，EPSRC最近的国际化学评论（IRC）强调了英国化学生物学的世界领先地位，并将其归类为EPSRC投资组合的“增长”领域。这项研究将巩固英国在这一领域的地位。此外，这里的发展将支持合成生物学的活动，这是英国政府的“八大技术”之一。事实上，这项工作尤其及时，因为合成生物学现在正处于从基础研究向具有更广泛影响的实际应用过渡的风口浪尖。

Plastics are a broad range of solid polymeric materials that have found widespread application as industrial components and consumer goods. However, there has been a steady accumulation of discarded plastics throughout the world, and there is now growing awareness that they present a significant hazard to the natural environment and human health. In relation to these concerns, there is increasing emphasis on the recovery (and subsequent reuse) of plastic materials, or their conversion into other materials than can serve as feedstocks for new products.Some enzymes that catalyse oxidations in the decomposition of biomass are known to convert compounds that are usually resistant to other types of chemical reactions; and have therefore been proposed to be able to decompose plastics. This project will aim to investigate the application of a range of oxidative enzymes for the degradation of plastics that contain chemically unreactive C-C, C-H and C-O chemical bonds, for which there are currently no viable reprocessing methods. Thus, the research will involve the chemical synthesis of small molecule models of the plastics, heterologous production of the enzymes, testing of the enzymes with the model molecules and mechanistic studies of the enzymatic reactions by a range of analytical methods (spectroscopic, electrochemical and chromatographic). By using small model molecules, it is intended that detailed chemical reactivity information can be gathered, which will enable a more rational approach to the subsequent reengineering of any promising enzyme candidates for this application. Subsidiary research objectives include investigations of the physicochemical properties of candidate enzymes that are relevant for the processing of plastic materials, such as identifying the tolerance of enzymes towards organic solvents, and their thermostability. The application of oxidative enzymes for this purpose is currently poorly explored and has largely been conducted in a piecemeal manner, resulting in empirical observations that are difficult to rationalize (and therefore to further exploit). This research will aim to fill this knowledge gap. From a strategic perspective, the EPSRC's most recent International Review of Chemistry (IRC) highlighted the UK's chemical biology as world-leading, and it is classified as a "grow" area of the EPSRC portfolio. This research will consolidate the UK's position in this area. Furthermore, the developments here will underpin activities in synthetic biology, which is amongst the UK Government's "Eight Great Technologies". Indeed, this work is particularly timely since synthetic biology is now at the cusp of transitioning from fundamental research to tangible applications withwider impact.