Rudina Bleta, Cedric Decarpigny, Anne Ponchel and Eric Monflier
Supramolecular hydrogels have attracted increasing interest in recent years because of their ability to incorporate high levels of proteins, cells, antibodies, peptides and genes. In this work, we propose a new approach to confinement of Candida Antarctica lipase B (CALB) within a supramolecular silicified hydrogel based on Pluronic F127 and α-cyclodextrin (α-CD). After functionalization of the matrix, the catalytic performance of the supported biocatalyst was evaluated in the oxidation of 2,5-diformylfuran (DFF) to 2,5-furandicarboxylic acid (FDCA), a fully biosourced alternative to terephthalic acid used in the production of polyethylene terephthalate (PET). Our results revealed that while CALB immobilized in conventional sol-gel silica yielded exclusively 5-formylfuran-2-carboxylic acid (FFCA), confinement of the enzyme in the silicified hydrogel imparted a 5-fold increase in DFF conversion and afforded 67% FDCA yield in 7 h and almost quantitative yields in less than 24 h. The hierarchically interconnected pore structure of the host matrix was found to provide a readily accessible diffusion path for reactants and products, while its flexible hydrophilic-hydrophobic interface was extremely beneficial for the interfacial activation of the immobilized lipase.
