The goal of this study was to define the partitioning behavior of chitinase from Trichoderma spp. in soy lecithin liposomes, using a thermodynamic approach based on the partitioning variation with temperature. An effort has been made to define the liposomes, as well as free and immobilized enzyme stability during storage at 4 and 25 A degrees C. The partition coefficients (K (o/w)) were greater than 1; therefore, the standard free energies of the enzyme transfer were negative, indicating an affinity of the enzymes for encapsulation in liposomes. The enthalpy calculation led to the conclusion that the process is exothermic. The presence of enzyme decreased the liposome storage stability from 70 days to an approximately 20 days at 25 A degrees C and 30 days at 4 A degrees C. Monitoring of the liposome's diameter demonstrated that their size and concentration decreased during storage. The liposome's diameters ranged from 1.06 to 3.30 mu m. The higher percentage of liposome corresponded to a diameter range from 1.06 to 1.34 mu m. This percentage increased during storage. There were no evidences for liposome fusion process. The stability of immobilized enzyme was increased in comparison with free chitinase.