Stability and reactivity of acid phosphatase immobilized on composite beads of chitosan and ZrO2 powders

作者：Chang Min Yun; Juang Ruey Shin^*

来源：International Journal of Biological Macromolecules, 2007, 40(3): 224-231.

DOI：10.1016/j.ijbiomac.2006.07.009

• acid phosphatase
• immobilization
• chitosan-ZrO2 composite
• stability
• reactivity
• thermal deactivation energy

Equal weights of chitosan and ZrO2 powders were mixed in acetic acid solution to prepare the composite beads. They were then cross-linked with glutaraldehyde and stored with and without freeze-drying before use. The physicochemical properties of acid phosphatase immobilized on four types of the supports (wet/dried pure chitosan beads, wet/dried chitosan-ZrO2 Composite beads) were compared. Various parameters including glutaraldehyde concentration, cross-linking time, enzyme concentration, temperature, and pH on enzyme activity were studied. It was shown that the activity yield of enzyme immobilized on the dried chitosan-ZrO2 beads was the highest, and the relative activity remained above 83.2% within pH 2.9-5.8. Regardless of wet or dried beads, the Michaelis constant Km and maximum rate of reaction V-max of acid phosphatase immobilized on chitosan-ZrO2 composite beads were 1.8 times larger than those on pure chitosan beads. Of the four immobilized enzymes, the use of wet chitosan-ZrO2 bead as the support showed the lowest thermal deactivation energy (78 U mol(-1)).

• 出版日期2007-2-20