Department of Chemistry of Natural and Microbial Products, National Research Center, Dokki, Giza, Egypt.
Carbohydr Polym. 2013 Feb 15;92(2):1463-9. doi: 10.1016/j.carbpol.2012.10.061. Epub 2012 Oct 30.
The Aspergillus niger NRC1ami pectinase was evaluated according to its hydrolysis efficiency of dry untreated orange peels (UOP), HCl-treated orange peels and NaOH-treated orange peels (HOP and NOP). Pectinase was entrapped in polyvinyl alcohol (PVA) sponge and the optimum pH and temperature of the free and immobilized enzymes were shifted from 4, 40 °C to 6, 50 °C respectively. The study of pH stability of free and immobilized pectinase showed that the immobilization process protected the enzyme strongly from severe alkaline pHs. The immobilization process improved the enzyme thermal stability to great instant. The unique feature of the immobilization process is its ability to solve the orange juice haze problem completely. Immobilized enzyme was reused 12 times in orange juice clarification with 9% activity loss from the original activity. Maximum reaction rate (V(max)) and Michaelis-Menten constant (K(m)) of the partially purified form were significantly changed after immobilization.
黑曲霉 NRC1ami 果胶酶根据其对未处理干橙皮（UOP）、HCl 处理橙皮和 NaOH 处理橙皮（HOP 和 NOP）的水解效率进行了评估。果胶酶被包埋在聚乙烯醇（PVA）海绵中，游离酶和固定化酶的最适 pH 和温度分别从 4、40°C 变为 6、50°C。游离和固定化果胶酶的 pH 稳定性研究表明，固定化过程能使酶在强碱性 pH 条件下受到强烈保护。固定化过程极大地提高了酶的热稳定性。固定化过程的独特之处在于它能够完全解决橙汁浑浊问题。固定化酶在澄清橙汁中重复使用了 12 次，从原始活性损失了 9%的活性。部分纯化形式的最大反应速率（V(max)）和米氏常数（K(m)）在固定化后发生了显著变化。
