RESUMO
White-rot fungus manganese peroxidase (MnP) oxidizes a wide range of substrates, rendering it an interesting enzyme for potential applications. The stability of MnP can be improved by immobilization. With sodium alginate, gelatin, or chitosan as a carrier, and glutaraldehyde as the crosslinking agent, MnP was co-immobilized using the embed-crosslinked method and the adsorb-crosslinked method. The immobilization conditions and the partial properties of the three immobilized enzymes were investigated. When compared with the free enzyme, the optimum pH values and the temperatures of the three immobilized MnPs carried by alginate, gelatin, and chitosan were respectively shifted from 7.0 to 5.0, 5.0, 3.0 and from 35 degrees C to 75 degrees C , 55 degrees , 75 degrees C . The thermostabilities of the three immobilized MnPs were considerably better than that of the native enzyme. The chitosan-decreased by less than 5% even after repeated use for 6 - 9 times. The ability of decolorizing azo dyes in static and shaky situation by gelatin-immobilized MnP approached to the free enzyme, and there was no loss of enzyme activity during 2 repeated batch reactions.