Selective Oxidation of 5‐Hydroxymethylfurfural to 2,5‐Diformylfuran in Biphasic Media using Immobilized Galactose Oxidase: Proof of Concept and Limitations

• Published in: ChemCatChem 2024-02, Vol.16 (4), p.n/a
• Main Authors: Milić, Milica, Byström, Emil, Domínguez de María, Pablo, Kara, Selin
• Format: Article
• Language: English
• Subjects: 5-hydroxymethylfurfural (HMF); Adsorption; Aqueous solutions; biocatalysis; biphasic systems; enzyme immobilization; Galactose; galactose oxidase; Hydroxymethylfurfural; Oxidase; Oxidation; Poisoning (reaction inhibition); Refining; Stability analysis
• ISSN: 1867-3880; 1867-3899
• DOI: 10.1002/cctc.202301384

The oxidation of 5‐hydroxymethylfurfural (HMF) to 2,5‐diformylfuran (DFF) is a key reaction in valorizing biomass. DFF is hardly soluble in water, while HMF is often obtained from biorefineries in crude wet organic fractions. Thus, the reaction is challenging for both biocatalysis performed in aqueous media, and for chemocatalysis where the presence of water often results in catalyst poisoning. Galactose oxidase (GalOx) can selectively oxidize HMF to DFF and displays promising activity in aqueous‐organic media. In this study, GalOx was immobilized on ten carriers, assessing the immobilization yield, activity, and stability. Covalently immobilized GalOx catalyzed the oxidation of HMF to DFF in neat and water‐saturated EtOAc, and in biphasic systems of various water contents. At 50 % v/v H2O, the reaction was conducted at a semi‐preparative scale (50 mL) with no adverse effect on DFF yield. Some limitations arise, such as enzyme deactivation, and adsorption of DFF to the support, particularly in the aqueous fraction. Future options to upgrade the route may include designed stable enzymes under the presence of HMF/DFF, and the setup of microaqueous systems where DFF adsorption is minimized. The use of wet EtOAc media would be a promising approach in future biorefineries employing inexpensive crude wet organic fractions. Galactose oxidase (GalOx) immobilized on Purolite® LifetechTM ECR8215F catalyzed the oxidation of 5‐hydroxymethylfurfural (HMF) to 2,5‐diformylfuran (DFF) in ethyl acetate (EtOAc)‐based biphasic media, as well as neat and water‐saturated organic solvent. The results showcase a scalable system with an efficient catalyst with reusability potential.