Enzyme immobilization on amphiphilic polymer particles having grafted polyionic polymer chains

Abstract

Previously, we have shown that amphiphilic polymer particles functionalized with both hydrophilic guanidino groups and hydrophobic acyl groups have been shown to immobilize a large amount of lipase with the immobilized lipase retaining high transesterification activity in organic solvent. However, the stability of immobilized lipase in organic solvent was found to be insufficient. In the present study, the chemical environment surrounding the immobilized enzyme was made more hydrophilic in order to enhance the stability of immobilized lipase in organic solvent. For this purpose, polyionic polymer chains containing amino group in addition to amphiphilic groups were introduced. Monodisperse acrylic polymer particles (∼10 μm) were synthesized by seed polymerization in the presence of pore forming agent, and subsequently modified with poly(allylamine) and various reagents to introduce amphiphilic functional groups. The half-life of Rhizopus delemar lipase immobilized on these macroporous amphiphilic polymer particles in hexane was 2.46 times high compared to lipase immobilized on amphiphilic polymer particles with guanidino and stearoyl groups.