Enzyme Encapsulation in Mesoporous Metal-Organic Frameworks for Selective Biodegradation of Harmful Dye Molecules

Microperoxidase-8, a small, peroxidase-type enzyme was immobilized into nanoparticles of the mesoporous and ultra-stable metal-organic framework (MOF) MIL-101(Cr). The immobilized enzyme fully retained its catalytic activity and exhibited enhanced resistance to acidic conditions. The biocatalyst was reusable and showed a long-term stability. By exploiting the properties of the MOF's framework, we demonstrated, for the first time, that the MOF matrix could act in synergy with the enzyme (Microperoxidase-8) and enhance selectivity the oxidation reaction of dyes. The oxidation rate of the harmful negatively charged dye (methyl orange) was significantly increased after enzyme immobilization, probably as a result of the pre-concentration of the methyl orange reactant owing to a charge matching between this dye and the MOF.