超细SiO_2颗粒的制备及其用于酶的吸附固定化研究
文献类型：学位论文
| 作者 | 王玲玲 |
| 学位类别 | 硕士 |
| 答辩日期 | 2000-05 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 杨传芳 ; 唐芳琼 |
| 关键词 | 二氧化硅 超细颗粒 二氯二甲基硅烷（DDS） α-淀粉酶 固定化 |
| 其他题名 | Preparation of Ultrafine Silica and Its Application in Enzyme Immobilization |
| 学位专业 | 分离科学与工程 |
| 中文摘要 | 本文在三种不同类型表面活性剂开成的反胶团体系中制备了SiO_2超细颗粒，并在此基础上对颗粒进行表面改性，进一步研究表面修饰前后的SiO_2颗粒对酶吸附特性的影响，主要包括酶的吸附量、固定化酶的酶活性及其吸附稳定性。实验结果表明：用非离子表而活性剂TritonX-100和阴离子表面活性剂AOT两类反胶团体系均可制备单分散的SiO_2超细颗粒，但两种体系中水含量(w_0)对颗粒粒径的影响呈现相反的趋势：AOT体系中粒径随水含量的增大；而TritonX-100体系中颗粒粒径随水含量的增加而减小。用阳离子表面活性剂TOMAC体系无法合成SiO_2超细颗粒。对反胶团法和传统的Stober方法制备的SiO_2颗粒粒径标准偏差、粒度分布进行对比发现，反胶团法中AOT体系颗粒粒径标准偏差随粒径的增加而增大，TritonX-100体系标准偏差随粒径的增加变化不大；而Stober方法中标准偏差随粒径的增大而减小。制备粒径小于100nm的SiO_2颗粒，反胶团法明显优于Stober方法，粒径相对标准偏差较低；而对于粒径大于100nm的颗粒，Stober方法仍不失为一种很好的制备途径。酶吸附研究表明，用同一种载体固定α-淀粉酶，酶活性随酶吸附量的增加而增大，最终达到一平衡值。SiO_2颗粒经过二氯二甲基硅烷（DDS）表改性后，形成了疏水性表面。用修饰后颗粒固定α-淀粉酶，酶吸附量显著提高，但同时酶活性有所下降。实验发现，对未修饰载体，粒径小于100nm的SiO_2颗粒对α-淀粉酶的吸附量略低于多孔微米级颗粒；当经过DDS表面改性后，前者对酶的最大吸附量反而稍高于多孔颗粒。吸附酶的活性强烈依赖于不同粒子载体，固定化酶活性大小次序为:SiO_2(50nm) > SiO_2(1μm) > SiO_2(50nm)/DDS > SiO_2(1μm)/DDS。另外，通过表面修饰可以有效增加固定化酶的吸附稳定性。经过修饰的固定化酶，洗涤七次后酶活性仅损失30%，而未经修饰的固定化酶洗涤四次酶活性就损失了50%左右。 |
| 英文摘要 | Monodispersed ultrafine silica particles were prepared by using reverse micelles and Stober methods respectively. Synthesis conditions were carefully optimized for controlling the particles' morphology, size and their size distribution. Silica particles with different size were then surface modified with dichlorodimethylsilane (DDS). Their performance on immobilization of α-amylase was systematically studied. It was found that in the anionic surfactant based system, AOT /Cyclohexane/NH_(3~·)H_2O reverse micelles, the particles' size prepared increases as the water to surfactant molar ratio (w_0) rises up. While in the non-ionic surfactant based system, TritonX-100 /Hexanol/ Cyclohexane /NH_(3~·)H_2O reverse micelles, the particle size decreases as w_0 rises up. And it seems impossible to prepare SiO_2 in cationic surfactants based reverse micelles, such as TOMAC system. Meanwhile, the particle size distributions and standard deviations were also compared among different methods. Results show that reverse micellar method is more suitable for synthesis of the silica particle with diameter below 100nm and with a lower deviation than Stober method. But the latter is still a good method for preparing larger silica particles, for example, larger than 100nm. The adsorption behavior of α-amylase on silica particles was investigate before and after modification by DDS. Adsorption amounts of α-amylase and the activities of adsorbed α-amylase were measured under various adsorption carriers. The amount of adsorption was strongly affected by the type of particles and increased with increasing surface hydrophobicity. The activities of adsorbed α-amylase on unmodified SiO_2 were higher than those on the DDS modified ones. For the same SiO_2 carrier, the activities increased with increasing the adsorption amount of α-amylase. Although at lower enzyme concentrations, the adsorption amount on the silica particle with diameter of 50nm was lower than that on the porous ones with 1000nm diameter, the immobilized α-amylase on the former carrier had a higher activity than on the latter. The catalytic stability of α-amylase was remarkably enhanced after modification with DDS. The immobilized enzyme on the modified carrier only losed 30% activity when it was washed seven times, while the enzyme on the unmodified one losed about 50% of its initial activity after being washed four times. |
| 语种 | 中文 |
| 公开日期 | 2013-09-26 |
| 页码 | 64 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1937]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 王玲玲. 超细SiO_2颗粒的制备及其用于酶的吸附固定化研究[D]. 中国科学院研究生院. 2000. |
入库方式： OAI收割
来源：过程工程研究所
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