Lei Zhongli, Ren Na, Li Yanli, Li Na, Mu Bo
Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, School of Chemistry and Materials Science, Xi'an 710062, China.
J Agric Food Chem. 2009 Feb 25;57(4):1544-9. doi: 10.1021/jf802913m.
Polymer nanocomposite microspheres (PNCMs) as solid supports can improve the efficiency of immobilized enzymes by reducing diffusional limitation as well as by increasing the surface area per mass unit. In this work, pectinase was immobilized on Fe(3)O(4)/SiO2-g-poly(PSStNa) nanocomposite microspheres by covalent attachment. Biochemical studies showed an improved storage stability of the immobilized pectinase as well as enhanced performance at higher temperatures and over a wider pH range. The immobilized enzyme retained >50% of its initial activity over 30 days, and the optimum temperature and pH also increased to the ranges of 50-60 degrees C and 3.0-4.7, respectively. The kinetics of a model reaction catalyzed by the immobilized pectinase was finally investigated by the Michaelis-Menten equation. The PSStNa support presents a very simple, mild, and time-saving process for enzyme immobilization, and this strategy of immobilizing pectinase also makes use of expensive enzymes economically viable, strengthening repeated use of them as catalysts following their rapid and easy separation with a magnet.
聚合物纳米复合微球（PNCMs）作为固体载体，可以通过减少扩散限制以及增加单位质量的表面积来提高固定化酶的效率。在这项工作中，果胶酶通过共价连接固定在Fe(3)O(4)/SiO2-g-聚（对苯乙烯磺酸钠）纳米复合微球上。生化研究表明，固定化果胶酶的储存稳定性得到改善，并且在较高温度和更宽的pH范围内性能增强。固定化酶在30天内保留了其初始活性的50%以上，最佳温度和pH也分别提高到50-60℃和3.0-4.7的范围。最后通过米氏方程研究了固定化果胶酶催化的模型反应动力学。聚对苯乙烯磺酸钠载体为酶固定化提供了一个非常简单、温和且省时的过程，这种固定化果胶酶的策略还使昂贵的酶在经济上可行，在通过磁铁快速轻松分离后，加强了它们作为催化剂的重复使用。
