| dc.description.abstract | Enzymes have been widely used in industrial applications due to their high efficiency and specificity in catalyzing reactions. However, there are lots of restrictions owing to their instability in harsh environments and their difficulty in separating from productions in the reaction solution. Therefore, it is particularly important and potential for enzyme immobilization that can increase the stability and practicality of the enzyme. In our previous report in 2015, we developed an innovative in-situ de novo synthesis method to encapsulate catalase with a zeolitic imidazolate framework-90, ZIF-90 a sub group of Metal-organic Frameworks (MOFs), at room temperature under aqueous in which MOFs is capable of protecting embedding enzyme from protease and maintaining its biological activity. In 2017 our laboratory published a further study on biocomposites. The MOFs is able to provide spatial confinement for enzymes, reducing the structural expansion under the environment of denature reagent, urea. However, the small pores of the zeolitic imidazolate framework limit the selectivity of enzymes and substrates.
Therefore, our laboratory had reported about encapsulating enzymes with large-pore metal-organic frameworks such as UIO-66 and Zn-MOF-74 via mechanochemistry, ball-milling, method in order to expand the applications of biocomposites.The ball-milling method only requires a few amounts of solvent, and the energy transfer during synthesis is very efficient, also it is a very green method. However, mechanochemistry has encountered problems such as enzymes slightly denatured during the ball milling process. To avoid this problem, and investigate the further study of large-pore metal-organic frameworks biocomposites, we look forward to developing a green synthesis method for obtaining MOFs with large-apeture under mild water-based at room temperature and extand more applications in industry. In this study, we found that CAT and CHT molecules can be encapsulated into Zn-MOF-74 materials, which has unique 1D hexagonal channels and nanometer-scale pore apertures, by using the de novo mild water-based approach under aqueous conditions at room temperature. The prepared CAT@Zn-MOF-74 and CHT@Zn-MOF-74 biocomposites retained the peroxidase and peptide digestion activities of CAT and CHT, respectively. The Zn-MOF-74 support provides an interesting size-sheltering effect and confers antiunfolding functions to CAT; it protects CAT from proteinase K and urea. This strategy not only provides a viable solution for developing biocomposites with better biocatalytic activities but also widens the spectrum of guests that can be embedded. As a pivotal first step, we firmly believe that the enzyme@MOF platform based on the de novo approach will pave the way for further applications owing to its extraordinary potential and performance. | en_US |