“Yolk-shell”结构中高效双酶级联催化体系的构筑

Construction of Efficient Bienzyme Cascade Catalytic System by“Yolk-shell”Structure

合成了一种生物-无机杂化材料ZIF-8@GOx-CPO@ZIF-8,该材料以具有“蛋黄-壳(Yolk-shell)”结构的金属有机框架(MOF)为载体,将葡萄糖氧化酶(GOx)和氯过氧化物酶(CPO)封装在不同隔离空间中构建了双酶纳米反应器.“Yolk-shell”结构可为封装的酶提供纳米邻近效应,GOx催化底物原位生成的H_(2)O_(2)可启动相邻的CPO催化反应,有效减少了反应物的扩散阻力和H_(2)O_(2)的分解和逃逸,同时避免了两种酶催化反应的相互影响.与均相缓冲液中的游离酶相比,ZIF-8@GOx-CPO@ZIF-8的级联催化效率更高.由于MOF的屏蔽效应,酶的热稳定性和有机溶剂耐受性显著提高.“Yolk-shell”结构还可有效抑制材料重复使用过程中酶分子的泄漏,经过20次重复使用后,ZIF-8@GOx-CPO@ZIF-8仍可保持初始级联催化效率的72%.将ZIF-8@GOx-CPO@ZIF-8双酶级联反应生成的HClO应用于偶氮染料的高效脱色和水果保鲜.在1 mg/mL ZIF-8@GOx-CPO@ZIF-8水溶液中,橙黄G(0.3 mmol/L)在15 min内可完成脱色(脱色率>98%).在新鲜草莓的杀菌保鲜实验中,ZIF-8@GOx-CPO@ZIF-8也显示出良好效果.ZIF-8@GOx-CPO@ZIF-8双酶级联催化体系具有高效、稳定、温和及绿色的特点,极具应用潜力.

This work proposes a bio-composite,ZIF-8@GOx-CPO@ZIF-8,which is constructed by“Yolk-shell”characteristic metal-organic framework(MOF)for specific division of glucose oxidase(GOx)and chloroperoxidase(CPO)by encapsulating them at different compartments.The structure of“Yolk-shell”can provide nano-proximity effect for encapsulated enzymes.H_(2)O_(2) generated in situ by GOx immediately starts the enzymatic reaction of adjacent CPO,effectively reducing the diffusion resistance of reactants and the decomposition and escape of H_(2)O_(2),and avoiding the interaction of the two enzymes during reuse.Compared with the free enzymes in the homogeneous buffer,the cascade catalytic efficiency of ZIF-8@GOx-CPO@ZIF-8 is improved.Owing to the shielding effect provided by the MOF,the thermal stability and organic solvent tolerance of the enzyme is also greatly improved.The“Yolk-shell”structure also effectively inhibits the leakage of enzyme molecules during the reuse process of the material.After 20 reuses,the bio-composite ZIF-8@GOx-CPO@ZIF-8 can keep 72%of the initial cascade efficiency.The cascade reaction of GOx-CPO can generate HClO,which is applied in efficient decolorization of azo dye and fresh-keeping of fruit.The decolorization of azo dye orange G(0.3 mmol/L)was almost completed in only 15 min with 98%decolorization efficiency by 1 mg/L of ZIF-8@GOx-CPO@ZIF-8.ZIF-8@GOx-CPO@ZIF-8 bienzyme cascade catalytic system is efficient,stable,mild and green with great application potential.