Immobilization of Laccase on Magnetic Carriers and Its Use in Decolorization of Dyes

摘要

Laccase from Trametes versicolor was immobilized on magnetic (Fe3O4) nanoparticles and microparticles. Free and immobilized laccase had activities 163 and about 4.6 nkat mg(-1) respectively. Immobilized was 125.8 mu g enzyme mg(-1) of nanoparticles and 13 mu g enzyme mg(-1) of microparticles. The K-m were 10.55, 9.02 and 11.14 mmol L-1 for free laccase, immobilized on nanoparticles and immobilized on microparticles. The pH optimum after immobilization was about 0.5 pH less than before immobilization. Immobilized laccase retained 55 % (nano) and 47 % (micro) of initial activity after nine repetitions. Values of T-50 calculated respectively for free laccase, immobilized on nanoparticles and microparticles at 54.5 degrees C, 57.5 degrees C and 46 degrees C. Dyes Direct Blue 78, Acid Blue 225, Reactive Red 195, Acid Blue 74, and Phenol Red were used for decolorization by free and immobilized laccase. Laccase was able to decolorize most of the dyes well.