Use of chemically modified PMMA microspheres for enzyme immobilization

Modified poly(methyl methacrylate) (PMMA) microspheres, about 7 μm in diameter, carrying aldehyde groups on their surfaces were synthesized and used as the support for enzyme immobilization. The immobilizing behavior as well as the properties of immobilized enzyme was studied. The amount of bound enzyme can be extended to 76.8 mg g−1 support, which is relatively much higher than other supports. The kinetic investigation derived from three typical models shows that the practical process is more complicated than the ideal condition, with one or more interactions being involved in the immobilization process. The Km value is actually larger and Vmax is smaller in the immobilized form than those in the free form. The increased resistance of the immobilized enzyme against the changes of temperature indicates that immobilizing enzyme onto the modified microspheres is useful for enzyme immobilization.