To obtain regenerable magnetic nanoparticles, triethoxy(3-isocyanatopropyl)silane and iminodiacetic acid (IZ) were used as the starting material and immobilized on Fe₃O₄ nanoparticles. Copper ions (Cu²⁺ ions) were loaded on the Fe-IZ nanoparticles and used for cellulase immobilization. The support was characterized by spectroscopic methods (FTIR, NMR) and thermogravimetric analysis, transmission electron microscopy, scanning electron microscope, X-ray diffraction, energy dispersive X-ray analysis, and vibrating sample magnetometer techniques. As a result of experiments, the amount of protein bound to immobilized cellulase (Fe-IZ-Cu-E) and cellulase activity was found to be 33.1 mg/g and 154 U/g at pH 5, 50°C, for 3 h. The results indicated that the free cellulase had kept only 50% of its activity after 2 h, while the Fe-IZ-Cu-E was observed to be around 77%, at 60°C. It was found that the immobilized cellulase maintained 93% of its initial catalytic activity after its sixth use. Furthermore, the Fe-IZ-Cu-E retained about 75% of its initial activity after 28 days of storage. To reuse the support material (Fe-IZ-Cu), it was regenerated by thorough washing with ammonia or imidazole.

中文翻译：

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用于纤维素酶固定化的可再生磁性纳米粒子的制备：提高酶活性和稳定性

为了获得可再生的磁性纳米粒子，以三乙氧基（3-异氰酸丙基）硅烷和亚氨基二乙酸（IZ）为起始材料并固定在Fe ₃ O ₄纳米粒子上。铜离子（Cu ²⁺离子）负载在 Fe-IZ 纳米颗粒上并用于纤维素酶的固定。通过光谱方法（FTIR、NMR）和热重分析、透射电子显微镜、扫描电子显微镜、X 射线衍射、能量色散 X 射线分析和振动样品磁力计技术对载体进行了表征。实验结果表明，与固定化纤维素酶 (Fe-IZ-Cu-E) 结合的蛋白质量和纤维素酶活性在 pH 5、50°C 下 3 小时分别为 33.1 mg/g 和 154 U/g . 结果表明，游离纤维素酶在 2 小时后仅保持 50% 的活性，而在 60°C 下观察到 Fe-IZ-Cu-E 约为 77%。发现固定化纤维素酶在第六次使用后仍保持其初始催化活性的 93%。此外，储存 28 天后，Fe-IZ-Cu-E 保留了约 75% 的初始活性。为了再利用支撑材料（Fe-IZ-Cu），它通过用氨水或咪唑彻底洗涤来再生。