Rhus laccase (RL) was immobilized on water-soluble chitosan (WSCT) and chitosan microsphere (CTMS) by various methods, and their properties were compared with transitional metal (Fe3+)-immobilized laccase in chelation. The immobilization yield (IY) on WSCT was not significantly affected by the methods used; the recovery activity of the enzyme had the relation: FeCl3-RL > RL-WSCT > RL-CTMS. The effects exist between the special dimension of the supports and the IY. After immobilization, the suitable pH and temperature of the enzyme were significantly improved. After three months at 4 degrees C, the losses of activity were 10% FeCl3-RL) 10% (RL-WSCT) and 15% (RL-CTMS), respectively; the activity remained 80% for RL-WSCT and 85% for FeCl3-RL after use 15 times. (c) 2006 Elsevier Ltd. All rights reserved.