Bovine liver catalase was immobilized into chitosan beads prepared in crosslinking solution. Various characteristics of immobilized catalase such as the pH-activity curve, the temperature-activity curve, thermal stability, operational stability, and storage stability were evaluated. Among them the pH optimum and temperature optimum of free and immobilized catalase were found to be pH 7.0 and 35 degreesC. The K-m value of immobilized catalase (77.5 mM) was higher than that of free enzyme (35 mM). Immobilization decreased in V-max value from 32,000 to 122 mumol (min mg protein)(-1). It was observed that operational, thermal and storage stabilities of the enzyme were increased with immobilization. (C) 2003 Elsevier Science Inc. All rights reserved.