▎ 摘　　要

NOVELTY - An aminosilylated magnetic oxidized graphene nanoparticle co-immobilized laccase and mediator system comprises laccase and mediator immobilized on an aminosilylated magnetic oxidized graphene nanoparticles. The content of mediator is 0.3-0.6 mmol with respect to 1 g co-immobilized laccase. After immobilization, the laccase activity is 120-300 U/g. USE - Aminosilylated magnetic oxidized graphene nanoparticle co-immobilized laccase and mediator system (claimed). ADVANTAGE - The aminosilylated magnetic oxidized graphene nanoparticle co-immobilized laccase and mediator system with improved electron transfer efficiency between laccase and substrate and improved enzyme utilization rate is prepared by economical method. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of aminosilylated magnetic oxidized graphene nanoparticle co-immobilized laccase and mediator system, which involves preparing graphene oxide by mixing graphite powder, potassium permanganate, concentrated sulfuric acid and phosphoric acid, controlling exothermic process such that temperature is less than 35 degrees C, heating mixture at 50 degrees C for 10-14 hours, cooling mixture to room temperature, adding 150 mL ice water and 10 mL 30% hydrogen peroxide, stirring mixture for 1-2 hours, washing, centrifuging and vacuum drying mixture, preparing iron(III) magnetic oxide graphene nanoparticles by mixing graphene oxide as solution, iron(II) chloride and iron(III) chloride under nitrogen protection, stirring mixture at 85 degrees C in water bath, adding ammonium hydrate solution, stirring mixture for 0.5-1 hour, separating black product, washing with deionized water until neutral surface modifying nanoparticles by placing iron(III) magnetic oxide graphene nanoparticles in aqueous ethanol solution, adding 3-aminopropyl triethoxysilane, stirring reacting mixture at 50 degrees C for 10 hours, washing and drying reaction product, to obtain surface-modified aminosilylated magnetic oxide graphene nanoparticles, placing surface-modified aminosilylated magnetic oxide graphene nanoparticles in glutaraldehyde solution for 2 hours, washing with deionized to remove excess glutaraldehyde, adding 4-amino-2,2,6,6-tetramethylpiperidine-1-oxide, mixing at room temperature for 5 hours, separating product and washing product to obtain mediator-grafted nanoparticles, adding laccase to acetic acid-sodium acetate buffer solution, adding mediator-grafted nanoparticles, reacting at 35 degrees C for 5 hours and washing with acetic acid-sodium acetate buffer solution.