Construction of Immobilized Enzymes with Yeast and Metal-Organic Frameworks for Enhanced Biocatalytic Activities

Metal-organic frameworks (MOFs) have become promisinghostmaterials for enzyme immobilization and protection. Herein, ZIF-8nanocubes were successfully self-assembled onto yeast as a biologicaltemplate to obtain hybrid Y@ZIF-8. The size, morphology, and loadingefficiency of ZIF-8 nanoparticles assembled on yeast templates canbe well-regulated by adjusting the various synthetic parameters. Particularly,the amount of water significantly affected the particle size of ZIF-8assembled on yeast. Through using a cross-linking agent, the relativeenzyme activity of Y@ZIF-8@t-CAT could be greatly enhanced and remainedthe highest even after seven consecutive cycles, with improved cyclingstability, as compared to that of Y@ZIF-8@CAT. In addition to theeffect of the physicochemical properties of Y@ZIF-8 on the loadingefficiency, the temperature tolerance, pH tolerance, and storage stabilityof Y@ZIF-8@t-CAT were also systematically investigated. Importantly,the catalytic activity of free catalase was decreased to 72% by 45days, while the activity of the immobilized catalase remained above99%, suggesting good storage stability. The present work demonstratesthat yeast-templated ZIF-8 nanoparticles have a high potential tobe used as biocompatible immobilization materials and are promisingcandidates for the preparation of effective biocatalysts in biomedicineapplications.

Automated summary

Metal-organic frameworks (MOFs) have shown potential as host materials for enzyme immobilization and protection. In this study, ZIF-8nanocubes were self-assembled onto yeast as a biological template to obtain hybrid Y@ZIF-8. The size, morphology, and loading efficiency of the assembled ZIF-8 nanoparticles on yeast templates could be controlled by adjusting synthetic parameters. The use of a cross-linking agent greatly enhanced the relative enzyme activity of Y@ZIF-8@t-CAT and improved its cycling stability.