Immobilization of cellulase from fungus trichoderma sp. on composite beads of chitosan and activated kaolin

Abstract

In the present study, the composite beads were successfully prepared using chitosan and activated kaolin, which had a diameter of approx. 4.5 mm and pore size of 10 - 50 pm. Cellulase was purified from liquid-state cultivation of Trichoderma sp. by using ion-exchange (DEAE- cellulose) and size-exclusion (Sephadex GlOO) chromatography, and was afterward immobilized on the composite beads with the yield of 78.7 %. The immobilization eíĩíciency, stabilities of composite particle and immobilized enzyme as well as operational stability were evaluated. The pH - and thermal stabilities of immobilized enzyme were significantly higher than those of the free enzyme (remaining activity increased 35 % as incubated at 60 °c and 22 % at pH 9.0). The immobilized enzyme has a reusability of at least 4 times. It remained more than 50 % of its activity after 12 limes of reuse.