Wu Xiuhong, Wang Shaoyan, Zhang Lina, Wu Lidong, Chen Yi
School of Chemical and Engineering, University of Science and Technology Liaoning Anshan Liaoning 114051 PR China.
Department of Chemistry, Massachusetts of Institute of Technology Cambridge MA 02139 USA.
RSC Adv. 2018 Oct 10;8(61):34823-34829. doi: 10.1039/c8ra06202a.
Separating a target product from a relatively complex bioreaction system is often difficult. In this work, a "smart" bioreaction system was developed by using the special characteristic of temperature-responsive polyurethane (TRPU). By combining solvent evaporation with a wet phase inversion technique, an asymmetric membrane consisting of an integral and dense skin layer supported by a porous sublayer was prepared from a thermally responsive polyurethane that experiences a sudden free volume increase upon heating through a phase transition temperature of 56 °C. Subsequently, the asymmetric TRPU membrane served as the carrier of an immobilized enzyme, wherein β-glucuronidase was multipoint-conjugated by using biotin and streptavidin on the porous sublayer. Then, the material-asymmetric TRPU membrane served jointly as the antennae as well as the actuator, which reversibly responds to temperature to switch (on-off) the access of the reactant glycyrrhizic acid (GL). Under the optimal temperature (40 °C) and pH (7.0) conditions, the immobilized β-glucuronidase contributed to almost 33% yield of glycyrrhetinic acid 3--mono-β-d-glucuronide (GAMG) of the isolated counterpart for the same concentration of substrate (250 mg L) reaction for 24 h, while costing 1% of that of the isolated β-glucuronidase. Kinetic results showed that and values were 8.89 × 10 mg L and 2.30 × 10 mg L h, respectively. The specific functional polymer-immobilized β-glucuronidase design serves as a bioreactor of GL into GAMG, as well as a separator deliberately irritated and controlled by temperature. This "smart" support material presents a potential facilitator for the separation of complex biotransformation reactions.
从相对复杂的生物反应体系中分离目标产物通常很困难。在本研究中，利用温度响应性聚氨酯（TRPU）的特殊特性开发了一种“智能”生物反应体系。通过将溶剂蒸发与湿相转化技术相结合，由热响应性聚氨酯制备了一种不对称膜，该膜由致密的整体皮层和多孔支撑层组成，当加热到56℃的相变温度时，该聚氨酯的自由体积会突然增加。随后，不对称TRPU膜用作固定化酶的载体，其中β-葡萄糖醛酸酶通过生物素和链霉亲和素在多孔支撑层上进行多点共轭。然后，材料不对称的TRPU膜同时作为天线和致动器，可逆地响应温度以切换（开启-关闭）反应物甘草酸（GL）的进入。在最佳温度（40℃）和pH（7.0）条件下，对于相同浓度的底物（250mg/L）反应24小时，固定化β-葡萄糖醛酸酶产生的甘草次酸3 - 单-β - d - 葡萄糖醛酸苷（GAMG）的产率几乎是游离对应物的33%，而成本仅为游离β-葡萄糖醛酸酶的1%。动力学结果表明， 和 值分别为8.89×10mg/L和2.30×10mg/L·h。特定功能聚合物固定化β-葡萄糖醛酸酶的设计用作将GL转化为GAMG的生物反应器，以及由温度故意刺激和控制的分离器。这种“智能”支撑材料为复杂生物转化反应的分离提供了潜在的便利。
