Synthesis And Activity Of Enzyme@MnO₂ Nanocomposite Enzyme Based On Biomineralization

Most enzymes are composed of proteins,produced by organisms and have high catalytic activity.They are green catalysts.But the enzyme has some disadvantages,such as its difficult to recover,limited catalytic ability and single enzyme function.Usually,researchers will use biological technology to recombine and evolve genes encoding enzymes or modify the enzyme protein molecules to improve the function of the enzyme.However,the process of operation is complex,cost-effective,time-consuming,and can not achieve enzyme immobilization,which increases the cost and benefit of enzyme use.Therefore,it is very important to study new materials and methods to realize the molecular evolution and immobilization of enzyme with more efficient,simple,economic and environmental protection.ObjectiveThis paper aims to study a new,simple and rapid method to realize enzyme evolution and immobilization around nanomaterials,so as to improve the related properties of the enzyme.Method1.Laccase and Horseradish peroxidase were used as "templates",Synthesis by biomineralization of Laccase@MnO2 Nanocomposite enzyme(Lac@MnO2)And Horseradish Peroxidase@MnO2 Nanocomposite enzyme(HRP@MnO2),The results showed that the nanocomposites were characterized by IR,Elemental Mapping analysis,X-ray photoelectron spectroscopy(XPS),Transmission electron microscopy(TEM).2.The enzyme activity of the two nanocomposites was studied by using three oxidation substrates ABTS(2,2 '-diazonibis(3-ethylbenzothiazoline-6-sulfonic acid),TMB(3,3',5,5 '-tetramethylbenzidine)and OPD(o-phenylenediamine),including the optimum temperature,p H,buffer solution and other conditions,and the enzyme activity parameters such as Km value were determined.3.Under the optimum temperature,p H and buffer solution,the difference between the catalytic efficiency of the two kinds of nanocomposites and the single enzyme catalytic efficiency was compared with that of the malachite green and indigo disulfonate under the optimum temperature,p H and buffer solution conditions,and the reuse rate of the nanocomposites for the degradation of organic pollutants was determined.Result1.IR,Mapping,XPS and TEM showed that Lac@MnO2 and HRP@MnO2 were successfully synthesized.2.The results showed that ABTS,TMB and OPD were used as oxidation substrates to confirm that both metal nanocomposites had high enzyme activity.Among them,Lac@MnO2 When ABTS is used as the substrate,the optimum temperature and p H of the oxidation are 40? and 2.0 respectively;When TMB was used as the substrate,the optimum temperature and p H of TMB were 30? and 4.0 respectively;The best buffer for both substrates was acetate sodium acetate buffer;HRP@MnO2 When ABTS is used as the substrate,the optimum temperature of oxidation is 30?,the optimum p H is 3.0,and the best buffer is citric acid buffer;When OPD is used as the substrate,the optimum temperature for oxidation is 60?,the optimum p H is 6.0 and the best buffer is B-R buffer.3.The degradation efficiency and reuse rate of malachite green and indigo disulfonate were measured by two kinds of nanocomposite enzymes.Compared with a single laccase,Lac@MnO2 The degradation efficiency of malachite green was increased by 5 times,and the degradation efficiency of indigo disulfonate increased by 10 times;Compared with a single HRP,HRP@MnO2 The results showed that the malachite green and indigo disulfonate could be degraded efficiently without H2O2.When H2O2 was added to degrade,the degradation efficiency of malachite green by composite enzyme increased by 1.2 times and that of indigo disulfonate was twice as high as that of single HRP.4.The degradation efficiency of organic pollutants such as peacock green can be maintained at more than 90% after 6 to 8 times.ConclusionThe research is based on the method of biomineralization Lac@MnO2 And HRP@MnO2 The two kinds of nanocomposites,ABTS,TMB and OPD as the oxidation substrate,confirmed that both of them had high enzyme activity,and determined the optimum temperature,p H value and buffer solution of the two kinds of composite enzymes when they oxidize different substrates.The degradation efficiency and reuse rate of malachite green and indigo disulfonate were further determined.The feasibility and reliability of the method were proved.