载体对包埋酶微环境的影响分析

包埋法固定化酶过程中,酶固定化载体的选择和设计是酶固定化过程的关键因素,适宜的载体微环境对酶活性和稳定性的影响尤为重要。论文首先分析并提出了影响固定化酶所处载体微环境的主要因素,包括载体的亲疏水性、结构形态和反应活性。载体的亲疏水性决定固定化酶微环境中的水分含量。载体的结构形态对酶形成的笼效应,以及载体的反应活性,包括共价键合、静电和氢键等的结合能力,影响酶构象的稳定性和运动性。另外,底物／产物的扩散速率和酶的可及性也同样受到载体的孔结构、孔分布以及载体反应活性的影响。本文介绍了常用的酶包埋载体,包括sol-gel二氧化硅、高分子水凝胶以及高分子－二氧化硅杂化凝胶固定化酶过程,结合上述影响酶微环境的因素,分析比较了三类载体固定化酶的包埋率、活性和稳定性,综述了为改善固定化酶微环境所进行改进研究的进展。

Analyzing the Effect of Carrier on the Microenvironment of Encapsulated Enzyme

It is very important to select and appropriate microenvironment for encapsulated design the carriers for enzyme encapsulation, especially to create the enzymes in the carriers. The key factors affecting the enzyme microenvironment in the carrier for enzyme encapsulation are analyzed and proposed in this review, including the hydrophilicity, the structure and morphology, and the reactivity of the carriers. Water content in the carrier is determined by its hydrophilicity. The enzyme stability and conformational transitions are impacted by the cage effect formed by the carrier structure and morphology, and by the reactivity of the carriers, such as the activity of covalent linking, hydrogen bonding and electrostatic interaction. Meanwhile, the diffusion properties of substrate/product and the enzyme accessibility are affected by fhe pore structure and distribution, and by the reactivity of carriers. Then encapsulation processes for normally used carriers are presented, including sol-gel silica, polymer hydrogel and polymer-silica hybrid composite. According to the factors mentioned above, the enzyme loading efficiency, catalytic activities, and stability of the three types of carriers for enzyme encapsulation are analyzed. Also promotions to modify the microenvironment of encapsulated enzymes in the three types of carrier are discussed.