Immobilization of dill (Anethum Graveolens L.) catalase and its properties

Over the last decade, enzyme immobilization has become more important in industry and biotechnology. In this study, catalase from dill (Anethum graveolens L.) plant was immobilized covalently with glutaraldehyde onto chitosan particles. The pH and temperature optima as well as the changes in the kinetics of the immobilized and free dill catalase were determined. The K-m value for immobilized catalase (35 mM) was higher about 1.5-fold than that of free enzyme (24 mM). Optimum temperature was observed at 40 degrees C, a 10 degrees C higher than that of the free enzyme and was significantly broader. The optimum pH was same for both free and immobilized catalase (pH 7.0). Immobilized catalase showed higher storage stabilities than free catalase. Thermal stability increased with immobilization. Free catalase lost all its activity, whereas immobilized catalase lost 45% of its activity within 60 days incubation period at 4 degrees C. Free catalase lost all its activity within 5 days, whereas immobilized catalase lost 65% of its activity within 60 days at 25 degrees C. The remaining activity of the catalase was about 70% after 10 cycles of batch operation. It was observed that operational, thermal and storage stabilities of the enzyme increased with immobilization. (c) 2012 Curtin University of Technology and John Wiley & Sons, Ltd