In this study, chitosan microspheres and sponges with uniform spherical and porous morphologies were prepared by coiling the stretched chains of chitosan with addition of salt and choosing different kinds of organic solvents as evaporation solvents. Cellulase was immobilized to the support by a covalent method. The enzyme exhibited a considerable affinity to the support, and the protein loading of 145.5 mg g(-1) support was fairly high. The immobilized cellulase had a higher Km than free cellulase and had better stability with respect to pH, thermal stability, reuses and storage stability than free cellulase. (c) 2005 Society of Chemical Industry.