[16-FAPESP-BE] Lignin valorization in cellulosic ethanol plants: biocatalytic conversion via ferulic acid to high value chemicals

木质素是一种存在于植物细胞壁中的聚合物，是地球上最丰富的可再生芳香物质来源。因此，木质素是生产可再生化学品的宝贵原料，这将有助于社会减少对原油的依赖，以生产化学品和塑料等材料。将木质素转化为可再生化学物质是一项非常困难的挑战，因为它很难分解，而且它非常不均匀（不同结构单元的混合物）。华威大学的研究人员最近发现了几种可以分解木质素的土壤细菌，以及可以氧化木质素的特定酶生物催化剂，并通过BBSRC/FAPESP FAPPA奖与巴西的CTBE合作，通过基因组测序确定了新的木质素降解酶，并开发了新的“生物传感器”，可用于设计重组木质素降解微生物，可以将木质素分解为高价值的化学品。该提案将纤维素乙醇生产和宏基因组DNA测序（CTBE）方面的专业知识与生物催化木质素增值（Warwick）和高价值化学品生产生物催化（曼彻斯特，UCL）方面的专业知识结合在一起。总体目标是利用合成生物学将木质素分解为中间体阿魏酸，在之前的工作中木质素通过细菌发酵产生阿魏酸，然后通过生物催化将阿魏酸转化为高价值化学品。该项目将：1)优化CTBE中试工厂生产纤维素生物乙醇的木质素流；2)利用合成生物学将木质素转化为阿魏酸；3)酶促阿魏酸转化为高价值的药物化学物质左旋多巴；4)从阿魏酸中生成高价值的香精化学品（醋酸松柏酯、异丁香酚）；5)扩大使用可再生原料生产化学品的规模；6)评估项目中开发的方法的技术和可持续性影响。

Lignin is a polymer found in plant cell walls, and is the most abundant source of renewable aromatic material on Earth. Lignin therefore represents a valuable raw material for generation of renewable chemicals, which will help society to reduce its dependance on crude oil for production of chemicals and materials such as plastics. Converting lignin into renewable chemicals is a very difficult challenge, because it is very hard to break down, and it is very heterogeneous (mixture of different structural units). Researchers at Warwick University have recently discovered several soil bacteria that can break down lignin, and specific enzyme biocatalysts that can oxidise lignin, and through a BBSRC/FAPESP FAPPA award have collaborated with CTBE in Brazil to identify new lignin-degrading enzymes through genome sequencing, and to develop new "biosensors" that could be used to engineer recombinant lignin-degrading micro-organisms that could break down lignin to high-value chemicals.The proposal brings together expertise in cellulosic ethanol production and metagenomic DNA sequencing (CTBE) with expertise in biocatalytic lignin valorisation (Warwick) and biocatalysis for high value chemicals production (Manchester, UCL). The overall aim is to use synthetic biology to break down lignin to intermediate ferulic acid, which has been generated from lignin via bacterial fermentation in previous work, and then to convert ferulic acid via biocatalysis into high-value chemicals. The project will : 1) optimise a lignin stream for the project from cellulosic bioethanol production at the CTBE pilot plant; 2) convert lignin into ferulic acid from lignin using synthetic biology; 3) enzymatically convert ferulic acid into a high-value pharmaceutical chemical, L-Dopa; 4) generate high value fragrance chemicals (coniferyl acetate, isoeugenol) from ferulic acid; 5) scale up chemicals production from renewable feedstocks; 6) assess the technical and sustainability impact of the methods developed in the project.