Immobilization of catalase onto chitosan and chitosan-bentonite complex: A comparative study

The immobilization of catalase onto chitosan and chitosan-bentonite was investigated and immobilization yield of 95.91 and 95.26 was obtained respectively. The optimum pH and temperature were found as 7.5 and 8.0 at 40 °C for free and immobilized enzyme. The value of Vmax decreased by 33,000-26,300, 24,500 μmol (min mg protein)−1 and Km increased by 12.5-25 and 20 mM for free and immobilized on chitosan and chitosan-bentonite respectively. The thermal stability, half life, FTIR analyses of the beads was also performed in order to characterise the structural differences. The remaining immobilized catalase onto chitosan and chitosan-bentonite activity was 50% and 70% after 20 cycles respectively. The storage stability were found as 22%, 60%, and 70% from its original activity in case of free enzyme and immobilization of chitosan, chitosan-bentonite beads respectively after 60 days.