Nanometer magnetic Fe3O4 particles were prepared by co-precipitation method.And with emulsification,the magnetic alginate nanopaticles were synthesized by taking Fe3O4 particles as nucleus,alginate as carrier.Then the magnetic particles were surface-modified with acyl chloride groups to immobilize laccase covalently.The conditions of immobilization of laccase were optimized by orthogonal design: 100 U/mL laccase 5 mL,and immobilizing for 30 min.Compared with the free enzyme,the affinity to substrate ABTS of...