Catalytic stability of turnip peroxidase in free and immobilized form on chitosan beads

Abstract

Chitosan beads were prepared, using glutaraldehyde as a cross linking agent for the immobilization of turnip peroxidase (TP). The morphology and structure of materials were examined by X-ray diffraction and scanning electron microscopy. The activity of free and immobilized TP was studied. The optimum pH was 7.0 for both free and immobilized enzyme and both were active in the temperature range between 30 oC and 50 oC. It was found that storage stability of the immobilized enzyme was better than that of the free enzyme. Both free and immobilized enzymes were used in the color removal of the dye Remazol Brilliant Blue R (RBBR). In discoloration experiments with immobilized TP, two phenomena were observed: discoloration, due to adsorption on the support (60.45%) and dye degradation, due to the enzyme action (27.50%). The free enzyme removed 62.86% of the color. The immobilized enzyme showed a potential of 61.17% for the removal of the dye color after 6 consecutive cycles.