The industrial utilization of savinase is mainly constrained by its stability limitations. In the present study, the irreversible thermoinactivation of savinase has been evaluated at 70 degrees C, and various possible mechanisms for irreversible thermoinactivation of savinase were examined. The main process seemed to be autodigestion of savinase at higher temperatures. To improve the thermal stability of the enzyme, the effect of two co-solvents (sorbitol and trehalose) on the enzyme's activity and stability was investigated. Both osmolytes prevented the autolysis of savinase at 70 degrees C without inactivating the enzyme; furthermore, the structural and kinetic stabilities of the enzyme increased in the presence of additives.