Structural and Functional Insights into the Biomineralized Zeolite Imidazole Frameworks

Biomineralization is a natural process of mineral formation mediated by biomacromolecules, allowing access to hierarchical structures integrating biological, chemical, and material properties. In this contribution, we comprehensively investigate the biomineralization of zeolite imidazole frameworks (ZIFs) for one-step synthesis of an enzyme-MOF biocomposite, in terms of differential crystallization behaviors, fine microstructure of resultant ZIF biominerals, the enzyme's conformation evolution, and protective effect of ZIF mineral. We discover that the biomineralization ability is ZIF organic linker dependent and the biocatalytic function is highly related to the ZIF mineral species and their distinguishable topologies and defect structures. Importantly, a side-by-side analysis suggests that the protective effect of ZIF mineral toward the hosted enzyme is highly associated with the synergistic effect of size dimension and chemical microenvironment of the ZIF pores. This work provides important insight into the ZIF-dependent biomineralization behaviors and highlights the important role of the ZIF microstructure in its biocatalytic activity and durability, which has been underestimated previously.