Novel Immobilization of Enzyme in Molecular Assembly of Nonionic Surfactant Adsorbed on Silica Gel

Abstract

As a novel procedure to immobilize enzymes, lysozyme was dissolved in the molecular assembly of the nonionic surfactant Triton X-100 adsorbed on silica gel. The adsorption isotherms of Triton X-100 on silica gel, and of lysozyme in the molecular assembly of adsorbed Triton X-100 on silica gel, were obtained. The isotherm for the latter are significantly influenced by pH and buffering agents, while the isotherms for the former are not. Moreover, the adsorption of lysozyme was affected by the ionic strength of the buffering agents. Leakage of immobilized lysozyme is influenced by pH and temperature; it is found that much lysozyme leaked when pH and temperature were low. However, under limited conditions the immobilized enzyme is very stable. The immobilized lysozyme was used in the enzymatic hydrolysis reaction of the water-soluble chitin derivative glycol chitin. The enzymatic reaction obeys the Michaelis-Menten mechanism and the values of kinetic parameter, Michaelis constant K_m and maximum velocity V_max, are estimated. The apparent activation energy E_a is also obtained.