One-pot photoenzymatic synthesis of maleic acid and its derivatives from bio-based furfural via catalytic cascades

Abstract

Recently, catalytic valorization of biomass-driven furfural has attracted great interest. In this work, we report a one-pot photoenzymatic route toward maleic acid (MA) and its C4 derivatives fumaric acid (FA) and D-malic acid (D-MalA) from furfural by cascade catalysis. Xanthine oxidase (XO) and Pseudomonas aeruginosa aldehyde dehydrogenase (PaALDH) were found to be good biocatalysts for furfural oxidation into 2-furancarboxylic acid (FCA), but the latter displayed much higher tolerance toward enzyme inactivation by reactive oxygen species generated by photocatalytic oxygenation. Besides, the enzyme inactivation might be considerably avoided by entrapping the photocatalyst eosin Y (EY) into a macroporous adsorptive resin NKA-II (EY@NKA). Galactose oxidase M_3-5 (GO M_3-5) could accept 5-hydroxy-2(5H)-furanone (HFO) as a substrate, whereas its variants M₄ and M_5-1 exhibited both higher activities and higher stability. Concurrent photoenzymatic production of MA from FCA was performed by merging EY@NKA with GO M₄/M_5-1, with yields of up to >99%. Nonetheless, simultaneous photoenzymatic conversion of furfural into MA failed, due to great enzyme inactivation. Therefore, a temporal compartmentalization strategy was applied for MA synthesis. A two-step process incorporating PaALDH, EY@NKA and GO M₄/M_5-1 was developed for furfural conversion, leading to the production of MA with 94% yield. In addition, the photoenzymatic cascade was facilely extended to produce FA and D-MalA by supplementing the corresponding biocatalysts, with 77–82% yields. The present work may pave the way for sustainable production of bio-based C4 chemicals.