Thermodynamics of laminarinase partitioning in soya lecithin liposomes and their storage stability

摘要

The goal of the present work is to define the partitioning behavior of laminarinase (EC 3.2.1.6) from Trichoderma spp. in soya lecithin liposomes using a thermodynamic approach based on the partitioning variation with the temperature. No information is available yet on use of laminarinase for microencapsulation in liposomes. An attempt has been made to define the stability of liposomes as well as free and immobilized enzyme during the storage under different conditions. The partition coefficients (K_(o/w)) were greater than 1, therefore the standard free energies of the enzyme transfer are negative, indicating an affinity of enzyme for microencapsulation in liposomes. The enthalpy calculation led to the conclusion that the process is endothermic. The transfer of laminarinase in liposomes is a entropy driven process attributable to positive value of entropy change. The presence of enzyme decreases the liposome storage stability from 70 days to an approximately 20 days at 25 C and 40 days at 4 C. Monitoring of the liposome's diameter demonstrates that their size and concentration decreases during storage. There was no evidence for liposome fusion process. The stability of immobilized enzyme in the buffer contained suspension did not increase in comparison with free laminarinase, however, stability increased in the soil and phytomass contained systems upon exposure to 254 nm UV-light for every 12 h. Thus the present study has theoretical input, as well as practical significance for enzyme application as biocontrol agent.