Immobilization of catalase by using Zr(IV)-modified collagen fiber as the supporting matrix

Collagen fiber (CF), an abundant natural material of biopolymer, was used as supporting matrix for immobilization of catalase. CF was firstly reacted with Zr(IV), then the catalase was immobilized on Zr(IV)-modified CF (Zr-CF) by adsorption. The structures and properties of Zr-CF and the Zr-CF immobilized catalase (Zr-CF-catalase) were characterized by means of DSC, SEM, FT-IR. etc. It was found that the denaturation temperature of CF was remarkably increased from 37 to 75.6 degrees C after reacting with Zr(IV). The amount of catalase immobilized on Zr-CF was 45.4 mg/g. The K-m and V-max values were 23.3 mM and 3.5 x 10(4) U/mg for free catalase and 30.2 mM and 1.3 x 10(4) U/mg for immobilized catalase, respectively. Compared with free catalase, the Zr-CF-catalase exhibited higher relative activity in a broad range of pH ;and temperature (pH 3.0-8.0, 15-75 degrees C). For example, the relative activity of immobilized catalase is still 70.3% at pH 3.0 and 25 degrees C and 62.2% at pH 7.0 and 75 degrees C. which is rather higher than 45.6% and 41.2% of the free ones at the same conditions. Furthermore, Zr-CF-catalase could be reused 70 times before complete deactivation and preserve 86.5% of its original activities after stored at room temperature for 12 days. (C) 2011 Elsevier Ltd. All rights reserved.