| Summary: | 2,5-furandicarboxylic acid (FDCA) synthesis has recently become a dynamic research topic due to the role of FDCA as the backbone of polyethylene furanoate (PEF), a 100% biobased alternative to plastic. However, there are relatively few examples of high-throughput processes for FDCA production. The main reasons are high costs, low productivity, and long reaction times. Moreover, there is no known one-step process, and the previously reported enzymatic cascades are often hindered by incompatible reaction steps. With the aim of establishing a truly green and sustainable production of FDCA, this PhD thesis showcases the development of a novel chemoenzymatic cascade. The substrate of this reaction is 5-hydroxymethylfurfural (HMF), a furan-based chemical synthesized from simple sugars, often obtained from food waste or the wood industry. In a triple oxidation reaction, HMF will be transformed into FDCA via 2,5 diformylfuran (DFF) using a combination of two enzymes – galactose oxidase (GalOx) and Candida antarctica lipase B (CalB). Firstly, the cascade was explored from the point of medium engineering, to develop the reaction steps in non-conventional media. Ethyl acetate (EtOAc) became the (co) solvent of choice, due to the exceptional stability of GalOx in its presence, where it retained over 80% of its activity over the course of 72 hours. Moreover, EtOAc plays an additional role as the substrate of CalB in the second reaction step. Reaction optimization ensued, with emphasis on the oxidation of HMF to DFF in ethyl acetate:buffer biphasic media, resulting in a three-fold increase in yield. This was followed by a scale up of the reaction to a 100 mL scale, as well as establishment of the whole cascade which resulted in production of FDCA with simultaneous in situ product removal via precipitation. With the aim of further improving the process, subsequent optimization efforts focused on individual reaction steps of the whole cascade. After a carrier screening, GalOx was covalently immobilized on a solid support, ...
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