新加坡国立大学杨昆霖教授做客第240期化苑讲坛

报告题目：Self-immobilized, Cross-linked Enzyme Aggregates(CLEAs) for Biocatelysis

报 告 人 ：杨昆霖教授

报告时间：2017年3月24日（周五）上午10：30

报告地点：东校区能量转换与存储材料化学教育部重点实验室二楼会议室(韵苑28栋)

报告人简介：

杨昆霖，1994年毕业于台湾大学化学工程系，1996年取得硕士学位。于1998年赴美国佐治亚理工学院深造，于2002年取得博士学位。期间，他以优异的成绩获得美国分子设计奖学金，并以电双层的研究得到美国化学学会最佳博士论文奖。同年，他前往威辛康辛大学麦迪逊校区从事博士后研究，专攻液晶在化学及生物传感器方面的应用。2005年，他取得新加坡国立大学的助理教授一职，并成立液晶及生物分子实验室，开启微流体传感器的研究方向。2012年荣升副教授并取得终生教职。在新加坡的这段时间，他在液晶传感器的研究取得重大突破，并且在SCI著名期刊包括Advanced Materials, Advanced Functional Materials, Langmuir 及 Biosensors and Bioelectronics发表多篇论文。此外, 他还是一位受学生欢迎的好老师，在各项教学评测中名列前茅，也是教学奖的常客，最近连续三年他都获得新加坡国立大学的最佳教学奖，并进入教学名人榜。

报告内容：

Enzymes have many advantages over inorganic catalysts but they are very sensitive to temperature and pH. Recently, we showed that enzymes can be immobilized as cross-linked enzyme aggregate (CLEAs) without using any solid carriers to improve their stability. Firstly, millifluidic reactors with two laminar flows of an enzyme solution and an organic solvent were employed to prepare uniform CLEAs of cellulase and laccase. CLEAs of cellulase had a size between 200 and 400 nm and were highly uniform. They can be collected on silica gels or entrapped in a membrane as practical biocatalysts to hydrolyze cellulose with an activity up to 86% of the free cellulase. Because of their large size, CLEAs can also be encapsulated in calcium alginate beads without any leaching problems. This features allowed CLEAs of cellulase to be reused and recycled up to 10 times for hydrolysis of cellulose. Similarly, CLEAs of laccase were prepared and entrapped in a membrane for oxidization of phenolic compounds. Trypan blue, a dye molecule, can be degraded by using membrane-bound CLEAs continuously for 96 h. Finally, glucose oxidase (GOx) and horseradish peroxidase (HRP) were co-immobilized as combi-CLEAs by using a coaxial-flow millifluidic reactor. The combi-CLEAs were used to catalyze cascade chemical reactions and minimize the decomposition of hydrogen peroxide in the presence of catalase. As a result, the overall reaction rate increased by 14 times compared to free enzyme mixtures in the presence of 6.3 mM of catalase. The combi-CLEAs were further exploited to develop colorimetric glucose assays with a limit of detection of 0.5 mM and a linear range up to 27.8 mM. In the future, millifluidic reactors can be used to prepare CLEAs with tunable sizes and properties for various industrial applications.