Construction Of Novel Enzyme Immobilization Systems And Their Application

Immobilized enzymes have been extensively used in many fields such as biocatalysts and biosensors, due to their good thermal stability, pH stability, reusability, and easy separation from the reaction syatems etc.. The property and structure of the substrate play an important role to the catalytic activity and property of the immobilized enzyme. Owing to their large surface area, high surface reactivity, and strong adsorption capacity, nano materials are ideal substrates for enzyme immobilization.In this thesis, horseradish peroxidase (HRP) was immobilized on nano-ZnO and the graphene oxide (GO). The catalytic activity, physical, and chemical properties of immobilized HRP as well as the interaction between HRP and GO was studied. The degradation of phenolic compounds with the immobilized HRP was explored.The activity of the nano-ZnO immobilized HRP systems is 40% higher than that of free HRP in alkaline environment. Immobilized HRP can maintain 45.3% activity at 60℃and 35.8% activity after 50 d storage. The ZnO immobilized HRP keeped 54.8% catalytic activity after the eight catalytic cycles.The GO immobilized HRP showed a similar property in the thermostability, active pH stability, and storage time. The application of the GO immobilized HRP in removal of phenolic compounds was sysmatically explored. The GO-HRP is more effective than free HRP in the removal of many phenolic compounds, especially 3-aminophenol.