s. sadeghzadeh

In this study, Fe3O4/CMC magnetic nanoparticles were synthesized through co-precipitation method. Afterward, laccase from Trametes hirsuta was immobilized onto Carboxymethyl cellulose (CMC)-coated magnetic Fe3O4 nanoparticles by covalent bonding between carboxyl groups of carboxymethyl cellulose and amine group of laccases. Also, the resulted magnetic nanoparticles and immobilized laccase were characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and dynamic light scattering (DLS) analysis. Moreover, the vital factors in enzyme immobilization, such as contact time, amount of N-hydroxysuccinimide (NHS), and the amount of nanoparticles were optimized, which successively 48 h, 0.01 g, and 0.0125 g were achieved for 0.01g of N-ethyl-N′-(3-dimethylaminopropyl)carbodiimide (EDC). Activity recovery of 51 ± 0.8% was achieved by optimizing the immobilization process. The results also indicated that the loading of laccase onto carboxymethyl cellulose-coated Fe3O4 nanoparticles was approximately 120 (mg/g). Finally, the immobilized laccases on magnetic support could save nearly 50% of their initial activity after five consecutive cycles.