轉酯化反應發展於微流道系統之研究

Abstract

近年來，隨著奈米科技的日益進步，微小化系統也逐漸備受重視。微小化系統是一門延伸各領域的學問，需要化學、物理、生物、光學等各工程學科的結合製作與設計。能夠建立一個微小型系統並直接快速地偵測其中的生物或化學分子，也就是將以往傳統大型複雜的分析裝置，提供體積縮小化、平行分析化、降低生產成本及縮短反應時間等優勢，將對於分析及研究上提供重大的貢獻。 傳統上對與轉酯化反應多是利用鹼製程來進行催化油脂以生產脂肪酸酯類，亦是生質柴油。因具有反應時間短、成本低廉等優點亦是目前有發展工業化的製程，但是其中的廢液處理也造成嚴重的環境污染問題。若是利用脂肪分解□來進行催化油脂以生產脂肪酸酯類，是具有無污染、環保的優勢。然而，較高的操作成本及冗長的反應時間是導致酵素製程不受青睞的最主要原因。對於脂肪分解酵素純化分離取得不易，再加上酵素無法進行重複回收再利用，所以價格相較於鹼製程來的高昂。因此本研究注重於發展出一個可以減少成本、縮小試劑體積及縮短反應時間的轉酯化反應偵測系統。 本研究中將利用微小化系統的優勢以探討生物分子於微流道系統的表現。由於在實驗中，脂肪分解□反應時間的長短取決於酵素的活性及酵素的安定性，因此將酵素經過固定化程序來進行提昇酵素活性及安定性為一個非常重要的步驟。我們利用化學蝕刻技術製作出形貌特徵為金字塔所形成的織構化表面，並結合自組裝技術來固定脂肪分解□，由於織構化的表面可用以增加脂肪分解□的鍵結及矽基材的穿透度，並進而發展出一套在微流道系統上偵測脂肪分解□催化三酸甘油脂反應的方法。 研究中利用偵測與分析轉酯化反應的方法有：藉由可見光與紫外光吸收光譜儀來測定，發現透射係數可以有判定的指標。實驗證實在不同反應時間中，穿透度有不同的變化，可用以觀察轉酯化反應的發生，然而此種光譜偵測的方法並不能確切地提供反應的轉化率；我們發現三酸甘油脂與脂肪酸酯類尾端氫原子化學位移的差異，並根據此差異來利用核磁共振儀偵測轉酯化反應，可以得到實際的反應轉化率；由於實驗中得知轉酯化反應對於光線有反應，因此我們利用這點結合太陽能板與微流道系統發展出一套光電偵測平台，並藉由特定波長的光訊號經由太陽能板以收集電子訊號。 實驗中，我們結合自組裝技術及化學蝕刻法以提高脂肪分解酵素經固定化程序的活性及安定性，並整合微流道系統來克服轉酯化反應中酵素製程的缺點。最後結合上述的偵測方法，以推測不同的方法對於轉酯化反應在微流道系統中的分析結果。

Recently, the microfluidic technology has become very important and widely used in many research fields such as biochemical technology, semiconductor technology and electronics technology. The microfluidic technology, the studies on the motion of fluid and particles through the microchannels, is an emerging field that has given rise to a large number of scientific and technological developments over the last years. In this study, we would like to develop a microfluidic reactor for production of the biodiesel of transesterification reaction. First, we immobilized lipase on the tetramethyl ammonium hydroxide (TMAH) textured surface with self-assembled monolayer (SAMs) of covalent bonding. The TMAH textured surface for anisotropic texturisation are usually growing pyramidal structures which are increasing the surface areas for lipase-immobilized and decreasing the reflectivity for advancing light absorption. The immobilization of lipase on solid substrate is an essential step for many applications in the field of biocatalysis duo to the relevance for the performance to improve and optimize the lipase activity and stability. However, the transesterification by enzyme method is time-consuming compared to acid- or alkali-catalyzed. Development the microfluidic reactor system is an important way to improving the reaction rate and enhancing the conversion yield due to the high surface-volume ratio and advancing the mass and heat transfer. This experiment aims is to provide a new approach that could potentially analyze the real-time reaction of transesterification. Moreover, new generation of biosensors combining new bioreceptors with the ever-growing number of transducers is emerging. The microfluidic reactor transducers of analysis systems are used in the optical spectroscopy (UV-Vis spectroscopy) for detecting the transmission of transesterification reaction. Following is detecting by nuclear magnetic resonance (NMR) for identifying the structure of biodiesel and then estimating the conversion of reaction. Since the response of transmission can be detected from transesterification reaction, the exploration of photo-electronic analysis, photodetector, can be used for monitoring the biocatalytic reaction in real-time. It is based on the phenomenon of different transmission and converted to electric signal. Since the detection of UV/Vis-NMR can confirm the conversion of transesterification and the detection of optical-electric (UV/Vis-photodetector) can be real-time monitoring the transesterification reaction. Combine with above analysis methods, the experiments provide a new approach for an easy and feasible way to analyze and detect the transesterification reaction.