Immobilization of xylan-degrading enzymes from Melanocarpus albomyces IIS 68 on the smart polymer Eudragit L-100.

Xylanase of Melanocarpus albomyces IIS 68 was immobilized on Eudragit L-100. The latter is a copolymer of methacrylic acid and methyl methacrylate and is a pH-sensitive smart polymer. The immobilization was carried out by gentle adsorption and an immobilization efficiency of 0.82 was obtained. The enzyme did not leach off the polymer even in the presence of 1 M NaCl and 50% ethylene glycol. The K(m) of the enzyme changed from 5.9 mg ml(-1) to 9.1 mg ml(-1) upon immobilization. The V(max) of the immobilized enzyme showed an increase from 90.9 micro mol ml(-1) min(-1) (for the free enzyme) to 111.1 micro mol ml(-1) min(-1). The immobilized enzyme could be reused up to ten times without impairment of the xylanolytic activity. The immobilized enzyme was also evaluated for its application in pre-bleaching of eucalyptus kraft pulp.