Bayramoglu Gulay, Celikbicak Omur, Kilic Murat, Yakup Arica M
Biochemical Processing and Biomaterial Research Laboratory, Gazi University, 06500 Teknikokullar, Ankara, Turkey; Department of Chemistry, Faculty of Sciences, Gazi University, 06500 Teknikokullar, Ankara, Turkey.
Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara, Turkey.
Food Chem. 2022 Jan 1;366:130699. doi: 10.1016/j.foodchem.2021.130699. Epub 2021 Jul 27.
In this work, magnetic chitosan (MCH) beads were synthesized by phase-inversion method, and grafted with polydopamine (PDA) and then used for direct immobilization of Candida rugosa lipase by Schiff base reaction. The amount of immobilized enzyme and the retained activity were found to be 47.3 mg/g and 72.8%, respectively, at pH 7.0, and at 25 °C. The apparent Km (9.7 mmol/L), and Vmax (384 U/mg) values of the immobilized lipase were significantly changed compared to the free lipase. The MCH@PDA-lipase was better thermal and storage stability at different temperatures than those of the free lipase. In hexane medium, the esterification reaction results showed that the maximum conversions of isoamylalcohol and isopentyl alcohol to isoamyl acetate and isopentyl acetate using the MCH@PDA-lipase were found to be 98.4 ± 1.3% and 73.7 ± 0.7%, respectively. These results showed that the MCH@PDA-lipase can be used as an operative immobilized enzyme system for many biotechnological applications.
在本研究中，采用相转化法合成了磁性壳聚糖（MCH）微球，并用聚多巴胺（PDA）进行修饰，然后通过席夫碱反应直接固定化皱褶假丝酵母脂肪酶。在pH 7.0和25℃条件下，固定化酶的量和保留活性分别为47.3 mg/g和72.8%。与游离脂肪酶相比，固定化脂肪酶的表观米氏常数（Km，9.7 mmol/L）和最大反应速率（Vmax，384 U/mg）值发生了显著变化。MCH@PDA-脂肪酶在不同温度下的热稳定性和储存稳定性均优于游离脂肪酶。在己烷介质中，酯化反应结果表明，使用MCH@PDA-脂肪酶时，异戊醇和异戊醇转化为乙酸异戊酯和乙酸异戊酯的最大转化率分别为98.4±1.3%和73.7±0.7%。这些结果表明，MCH@PDA-脂肪酶可作为一种有效的固定化酶系统用于多种生物技术应用。
