Highly efficient synergistic biocatalysis driven by stably loaded enzymes within hierarchically porous iron/cobalt metal–organic framework via biomimetic mineralization

Abstract

The integration of multimodal chemo-/bio-catalysis for efficient cascade reactions has long provided broad prospects in the field of biotechnology for ages. In this work, we describe the synthesis of a biomimetic multienzyme hybrid with hierarchically porous structure and outstanding catalytic activity via in situ encapsulation of natural enzymes in an iron–cobalt bimetallic metal–organic framework (Fe/Co-MOF, FCM). The combination of a single enzyme (glucose oxidase) or dual enzyme (β-galactosidase and glucose oxidase) with FCM resulted in remarkable synergistic biocatalysis ability; in contrast to simple biocatalyst mixtures in solution, the prepared multienzyme hybrid resulted in 3.2-fold and 2.1-fold improvements in activity for tandem reactions, respectively. The reinforced cascade bioactivity of the multienzyme hybrid benefitted from the synergistic effect between iron/cobalt in the FCM nanozyme, the opened substrate channel between enzymes/nanozymes, and the beneficial effect provided by the hierarchical MOF pores. The enlarged pores not only provided adequate space for immobilized proteins to diffuse and reorientate in FCM with low surface energy, but also reduced the intrinsic mass transfer obstacle to increase the diffusional efficiency of reactants/intermediates. In addition, on account of the shielding effect provided by FCM, the multienzyme hybrid exhibited enhanced tolerance towards severe circumstances and excellent reusability and has been successfully applied in small molecule detection, such as glucose and lactose. The current study highlights the superiority of synergistic bioreactors integrated with the MOF nanozyme and natural enzymes, suggesting great potential for applications in sustainable biomimetic catalysis.