College of Food and Biological Engineering, Jimei University, Xiamen 361021, China; Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Xiamen, Fujian Province 361021, China; The Research Center of Food Biotechnology, Xiamen 361021, China; Xiamen Key Laboratory of Marine Functional Food, Xiamen 361021, China.
College of Food and Biological Engineering, Jimei University, Xiamen 361021, China; Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Xiamen, Fujian Province 361021, China; Xiamen Key Laboratory of Marine Functional Food, Xiamen 361021, China.
Bioresour Technol. 2016 Apr;205:67-74. doi: 10.1016/j.biortech.2016.01.032. Epub 2016 Jan 19.
Tannase from Aspergillus tubingensis was immobilized onto carboxyl-functionalized Fe3O4 nanoparticles (CMNPs), and conditions affecting tannase immobilization were investigated. Successful binding between CMNPs and tannase was confirmed by Fourier transform infrared spectroscopy and thermogravimetric analysis. Vibrating sample magnetometry and X-ray diffraction showed that the CMNPs and immobilized tannase exhibit distinct magnetic responses and superparamagnetic properties. Free and immobilized tannase exhibited identical optimal temperatures of 50°C and differing pH optima at 6 and 7, respectively. The thermal, pH, and storage stabilities of the immobilized tannase were superior to those of free tannase. After six cycles of catalytic hydrolysis of propyl gallate, the immobilized tannase maintained over 60% of its initial activity. The Michaelis constant (Km) of the immobilized enzyme indicated its higher affinity for substrate binding than the free enzyme.
从土曲霉中提取的单宁酶被固定在羧基功能化的 Fe3O4 纳米粒子（CMNPs）上，并研究了影响单宁酶固定化的条件。傅里叶变换红外光谱和热重分析证实了 CMNPs 和单宁酶之间的成功结合。振动样品磁强计和 X 射线衍射表明，CMNPs 和固定化单宁酶表现出明显的磁响应和超顺磁性。游离单宁酶和固定化单宁酶的最佳温度相同，均为 50°C，但游离单宁酶的最适 pH 值为 6，而固定化单宁酶的最适 pH 值为 7。固定化单宁酶的热稳定性、pH 稳定性和储存稳定性均优于游离单宁酶。经过六次催化水解没食子酸丙酯的循环后，固定化单宁酶仍保持其初始活性的 60%以上。固定化酶的米氏常数（Km）表明其对底物结合的亲和力高于游离酶。
