A facile approach for hierarchical architectures of an enzyme–metal–organic framework biocatalyst with high activity and stability

Enzyme-incorporated composites with hierarchical porous structures can lead to improved performance of hybrid biocatalysts. Metal-organic frameworks (MOFs) have recently emerged as excellent biomineralizable materials for forming hybrid biocatalysts, offering superior performance for biocatalytic reactions. However, the small nanopores of MOFs significantly reduce the diffusion rates of small substrate molecules, hindering the contact between the inner active sites of an enzyme and the molecules, lowering the biocatalytic efficiency. Here, we used a solution-phase self-assembly method for preparing macroporous hierarchical porous architectures of a copper 5-(ethylthio)-1H-tetrazole [Cu(ett)] MOF, the distorted tetrahedral coordination geometry of which is favourable for producing macropores. Notably, the formation of [Cu(ett)] MOF hybrid biocatalysts is achieved via an in situ mineralization of enzymes, but without changes in the hierarchical porous structure. These properties lead to excellent catalytic activities as they decrease the inherent barriers to accelerate the diffusion rate of reactants. Moreover, the developed hierarchical porous MOFs demonstrated outstanding tolerance to inhospitable surroundings and favourable storage stability at room temperature.