ERA IB 5 A Synthetic Biology approach for bacterial bioconversion of lignin into renewable chemicals (LIGBIO)

木质素是一种聚合物，占植物生物量的15%-30%，工业上作为纸浆/造纸和生物燃料生产的低价值副产品生产。它含有酚类单体单元，因此它是一种可能的可再生芳香化学品来源，工业上需要这些化学品来制造塑料、药品和农用化学品，目前这些化学品是从原油中提取的。作为发展可持续的欧洲生物化学工业的努力的一部分，我们希望将木质素转化为可再生化学品，但由于其高度惰性的结构，尚未开发出将木质素转化为可再生化学品的商业工艺。最近，Bugg教授在Warwick的团队发现了两种新的细菌木质素降解酶，并表明可以通过基因修饰约氏红球菌RHA1中的木质素分解途径来产生香草醛，香草醛是一种用于食品/香料工业的化学物质。然而，目前对细菌中木质素分解的代谢途径和调控系统还不是很清楚。因此，在本项目中，我们将以恶臭假单胞菌KT2440为研究对象，以阐明木质素降解的代谢和调控网络。恶臭假单胞菌KT2440是一株木质素降解菌，其基因组已经测序，其芳香代谢网络是细菌中最知名的。然后，我们将利用这一知识对这种细菌进行重新编程，使用高活性的木质素降解酶来生产两种对生产可再生生物塑料感兴趣的目标化学物质。然后，我们将与工业合作伙伴Biome BioPlatform一起开发一种基于发酵的工艺，用于从木质素中生产可再生的芳香化学品。

Lignin is a polymer found as 15-30% of plant biomass, and is produced industrially as a low-value by-product of pulp/paper manufacture and biofuel production. It contains phenolic monomer units, hence it represents a possible renewable source of aromatic chemicals that are needed industrially to make plastics, pharmaceuticals and agrochemicals, currently derived from crude oil. As part of the effort to develop a sustainable European bio-based chemical industry, we wish to convert lignin into renewable chemicals, however, due to its highly inert structure, no commercial process has yet been developed for conversion of lignin to renewable chemicals. Recently Prof. Bugg's group at Warwick have discovered two novel bacterial lignin-degrading enzymes, and have shown that the lignin breakdown pathways in Rhodococcus jostii RHA1 can be modified genetically in order to generate vanillin, a chemical used in the food/flavour industry. However, at present the metabolic pathways and regulatory systems for lignin breakdown in bacteria are not well understood. Therefore, in this project we will study Pseudomonas putida KT2440, a lignin-degrading bacterium whose genome has been sequenced and whose aromatic metabolic network is the best known in bacteria, to elucidate the metabolic and regulatory networks for lignin degradation. We will then use this knowledge to reprogramme this bacterium, using high activity lignin-degrading enzymes, to produce two target chemicals that are of interest for the production of renewable bioplastics. With industrial partner Biome Bioplastics, we will then develop a fermentation-based process for the production of renewable aromatic chemicals from lignin.