Immobilization of Lipase on Three-Dimensionally Ordered Macroporous Silica Matrices by Covalent Bonding

• Main Author: 張文斌
• Other Authors: 李靜宜
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/45372131564313394983

碩士 === 明新科技大學 === 化學工程研究所 === 95 === Immobilization of enzymes is a technique that uses physical or chemical methods to convert soluble enzymes into immobile state. This technique grants the immobilized enzymes the virtues of easy recovery and reuse. However, the choice of immobilization matrix often affects the catalytic properties of the immobilized enzymes. Therefore, the development and evaluation of new immobilization matrices are often among the topics investigated in enzyme immobilization. In this research, three dimensionally ordered macroporous (3DOM) silica was employed as the matrix for lipase immobilization to investigate the relationship between matrix structure and enzyme activity. This research includes two parts. First, polystyrene was synthesized via emulsifier-free emulsification polymerization. By changing the amounts of free radical initiator and hydrophile solvent, we were able to prepare polystyrene latex particles of uniform size, in the range of 220 to 426 nm. Prehydrolyzed tetraethylorthosilicate was dripped on the template, namely, the centrifuged polystyrene latex particles, to form silica polystyrene composite. This silica polystyrene composite was calcined to remove polystyrene, resulting in 3DOM materials of pore size about 100~230 nm. Secondly, these materials were activated by 3-aminopropyltriethoxysilane, reacted with glutaradehyde, and finally covalently bounds with lipase to form immobilized lipase. About 240 mg crude lipase were immobilized in every gram of 3DOM matrix and the immobilized lipase exhibited a catalytic activity of 23~25 U/g matrix. As compared to the activity (about 15 U/g matrix) of lipase immobilized on mesoporous silica of smaller pore aperture (10~40 nm), the lipase immobilized in3DOM materials showed its advantages. It was quite clear that, although large enough to allow enzyme to enter, the pore size of matrix still affects the activity of immobilized enzyme.