Design of fine particles of silicon polymer highly effective as entrapping gel for biocatalysts functioning in organic media

硅聚合物细颗粒的设计可作为有机介质中生物催化剂的高效捕获凝胶

基本信息

批准号：
07650960
负责人：
KAWAKAMI Koei
金额：
$ 1.34万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Entrapment of lipase in organically modified silicates, which are derved from a mixture of tetramethoxysilane (TMOS) and alkyl group-containing organic silanes by the sol-gel method, leads to enhancement in esterification activity and thermal stability of immobilized preparation. In this study, we tried to form the lipase-entrapping gels either (1) in W/O microemulsion or (2) on the surface of support materials, and investigated some enzymatic properties of resultant immobilized lipase. In ester synthesis from butyric acid either isoamyl alcohol or ((]SY.+-。[))-menthol as a test reaction, the following results were obtained.(1) Microemulsion-based entrapment : Among various surfactants tested, the silicate-entrapped lipase prepared by using Brij 97 displayd a highest catalytic activity at room temperature. The organic-inorganic hybrid silicate derived from a mixture of TMOS and methyltrimethoxysilane resulted in a more enhanced activity of the immobilized lipase.(2) Dispersed entrapmen … More t on support surface : Among various organic silanes mixed with TMOS,alkyltrimethoxysilanes bearing longer chain length than propyl group, and methoxysilanes with multiple methyl groups brought about enhanced activity and thermostability of the immobilized lipase preparations. When kieselguhr such as commercially available Celite 545 was used as a support material, the entrapped lipase gave a mzximum esterification activity. There existed an optimum amount of gel and an optimum molar ratio of organic silane to TMOS.As the result of optimization of various preparation conditions, the thermostability of entrapped lipase was enhanced by 20-30ﾟC as compared with that of deposited counterpart.These results and findings might be ascribed to 1) stabilization of tertiary structure of protein globules by reasonably tight entrapment in close proximity of the hybrid gel surface, 2) preferential partitioning of substrates to the hydrophobic gel, and 3) hydrophobic interaction between lipase molecules and alkyl groups of the organic silica gel. Less

通过溶胶-凝胶法从四甲氧基硅烷 (TMOS) 和含烷基有机硅烷的混合物中捕获脂肪酶，可提高固定化制剂的酯化活性和热稳定性。我们尝试在（1）W/O 微乳液中或（2）在支撑材料的表面上形成脂肪酶包埋凝胶，并研究了一些以异戊醇或((]SY.+-.[))-薄荷醇为原料合成酯作为测试反应，结果如下。 (1) 获得基于微乳液的包埋：在测试的各种表面活性剂中，使用 Brij 97 制备的硅酸盐包埋脂肪酶在室温下表现出最高的催化活性。 TMOS 和甲基三甲氧基硅烷的混合物导致固定化脂肪酶的活性进一步增强。(2) 载体表面的分散包埋：在与 TMOS 混合的各种有机硅烷中，烷基三甲氧基硅烷的链长比丙基更长，甲氧基硅烷的链长比丙基更长。当硅藻土如市售的硅藻土时，多个甲基会增强固定化脂肪酶制剂的活性和热稳定性。以545为载体材料，包埋脂肪酶具有最大的酯化活性，存在最佳的凝胶量和最佳的有机硅烷与TMOS的摩尔比。通过对各种制备条件的优化，包埋脂肪酶的热稳定性较好。与沉积的对应物相比，温度提高了 20-30°C。这些结果和发现可能归因于 1) 蛋白质三级结构的稳定性通过在混合凝胶表面附近相当紧密的捕获来形成小球，2) 底物优先分配到疏水性凝胶，3) 脂肪酶分子和有机硅胶的烷基之间的疏水相互作用较小。