Study On The Co-Fixation Of Glucose Oxidase And Catalase By Nano-Mesoporous Silica Microcapsules

Immobilized glucose oxidase and catalase are currently the main methods for producing sodium gluconate in China.This preparation method has the advantages of simplicity,convenience,and high purity of the final product obtained.However,the poor stability and low reuse efficiency of enzymes hinder the application of this method in industrial catalysis.Therefore,the development of immobilized carriers has been widely recognized as a promising solution.The existing enzyme immobilization carriers are usually developed through covalent binding between the inactive site groups of enzyme molecules and the reaction groups on the carrier surface.Although this method improves stability,the conditions are harsh,the operation is complex,and strong reaction conditions are required,resulting in changes in the enzyme structure and low repeatability.Therefore,the development of efficient and repeatable immobilized enzyme carrier is the key to production.Based on the above research background,this paper designs a novel organic inorganic nanocomposite material for co-immobilization of glucose oxidase and catalase.The main research findings are as follows:（1）This paper first determined the optimal particle size of nano mesoporous silica for adsorbing protease at 100 nm,as well as the optimal p H,time,enzyme addition amount,GOD and CAT ratio for adsorption.In situ free radical polymerization method was used to adsorb protease loaded mesoporous silica（Protein@SiO₂）surrounded by a shell structure,nano mesoporous silica microcapsules were synthesized:Polymer@Protein@SiO₂.Subsequently,the success of synthesizing this nano mesoporous silica microcapsule was demonstrated through a series of characterization methods.（2）The enzymatic properties of proteases in Polymer@Protein@SiO₂ were studied,and the results showed that,the two enzymes in Polymer@Protein@SiO₂ not only maintain their original enzyme activity,but also improve their stability to low pH and high temperature.The distance between them in Polymer@Protein@SiO₂ is less than 10 nm,which is conducive to the cascade reaction of the two enzymes and lays a good foundation for the next industrial production of sodium gluconate.（3）By simulating the industrial catalytic process,compared with free enzyme,co-immobilized enzyme not only improves the temperature stability and acid stability,but also improves the storage stability.At the same time,it has a strong shear stress,which improves the inactivation and leakage of enzyme.Under high-speed rotation for four hours,more than 92%of the enzyme activity was still retained.After seven repetitions,the glucose conversion rate remained at 86%.In summary,we have developed and designed this organic-inorganic nanocomposite material Polymer@Protein@SiO₂,which not only improves the stability and stress resistance of enzymes,but also has a lower enzyme loss rate and higher conversion rate after multiple repetitions.This organic-inorganic nanocomposite material has great potential as a method for enzyme catalyzed production of sodium gluconate.