Lignin depolymerization/reconstruction using enzymatic and C-H activation catalysis

石油资源的使用是不可持续的，导致大气中二氧化碳的积累，这反过来又是我们星球全球变暖的原因。此外，地球上的石油资源正变得越来越稀缺。因此，以可持续的方式开发可再生生物质以获得散装和特种化学品正成为当代和后代的“必须”。木质纤维素生物质主要由纤维素、半纤维素和木质素组成，每年在自然界中大量产生。虽然糖部分已经被广泛研究转化为低分子质量的化学物质，但木质素部分仍然在很大程度上未被开发。在这个德国和法国的合作项目中，我们的目标是开发从聚合木质素开始制备高附加值分子的工艺。在第一步中，木质素将被酶解聚合，特别关注细菌-醚酶，以选择性地产生所需的单芳香化合物。在第二步中，使用新的C-H活化催化将这些进一步化学转化为高附加值的化学品。为了提供足够数量的所需木质素降解产物愈木酰基羟丙烷酮（GHP）和丁香基羟丙烷酮（SHP）用于化学升级，酶解木质素解聚过程将在效率、芳烃产量和不同木质素解聚酶活性的可能组合方面进行优化。此外，还将研究优化后的工艺升级。在单体升级部分，将制定新的方案，将GHP和SHP转化为4-甾体酮和新黄烷以及1-吲哚酮和二氢查尔酮，作为合成药物、农用化学品和化妆品以及聚合物材料单体的基础。总体而言，考虑到未来在工业环境中的实施，预计项目结果将促进木质素作为可再生原料的价值。

The use of petroleum resources, being not sustainable, leads to CO2 accumulation in the atmosphere, which in turn is the cause of global warming of our planet. Moreover, the earth’s petroleum resources are becoming scarcer and scarcer. Consequently, exploitation of renewable biomass to obtain bulk and speciality chemicals in a sustainable way is becoming “a must” for the present and future generations. Lignocellulosic biomass, consisting mainly of cellulose, hemicellulose and lignin, is produced in large quantities in nature every year. Whereas the sugar part has already been studied extensively for its transformation into low molecular mass chemicals, the lignin part remains largely underexplored. Within this collaborative project between Germany and France, we aim to develop processes allowing the preparation of high added-value molecules starting from polymeric lignin. In the first step, lignin will be depolymerized enzymatically, with a special focus on bacterial -etherases, to yield desired mono-aromatic compounds selectively. In the second step, these are further converted chemically into high added-value chemicals using novel C-H activation catalysis. To provide sufficient quantities of the desired lignin degradation products guaiacylhydroxypropanone (GHP) and (syringylhydroxypropanone (SHP) for chemical upgrading, the enzymatic lignin depolymerisation process will be optimized with regard to efficiency, aromatics yield and the possible combination of different ligninolytic enzyme activities. Moreover, upscaling of the optimized process will be studied. In the monomer upgrading part, emerging protocols will be developed for the conversion of GHP and SHP into 4-chromanones and neoflavanes as well as 1-indanones and dihydrochalcones to serve as building blocks in the synthesis of drugs, agrochemicals and cosmetics, as well as monomers for polymer materials. Overall, the project results are expected to advance the valorization of lignin as a renewable feedstock in view of a future implementation in an industrial context.