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 V(max) decreased by 33,000–26,300, 24,500 μmol (min mg protein)(−1) and K(m) 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.