Characteristics of glucose oxidase immobilized on Magnetic Chitosan Nanoparticles

Abstract Immobilization process is used to facilitate the enzyme recovery and reusability. The aims of this study were to evaluate the effect of different amounts of chitosan on immobilization efficiency of Glucose Oxidase (GOX), pH effect on enzyme activity and changes of kinetic characteristics of enzyme immobilized on Magnetic Chitosan Nanoparticles (MCNP). GOX was immobilized on MCNP with cross bonds and Schiff base covalent connections. The sample with 0.3 g of chitosan had the highest immobilization efficiency (41.30%). Morphology of nanoparticles was investigated by Scanning Electron Microscopy (SEM). Immobilization of GOX on magnetic nanoparticles was verified with Fourier Transform Infrared (FTIR). The effect of pH on enzyme activity was similar on both immobilized enzyme (IE) and free enzyme (FE). The evaluation of kinetic parameters for IE and FE has showed that the effectiveness factor was 0.45. Generally, it could be concluded that magnetic nanoparticles with 0.3 g chitosan could provide a suitable medium for immobilization of GOX.

摘要：固定化工艺用于实现酶的高效回收与重复利用。本研究旨在评估不同用量的壳聚糖对葡萄糖氧化酶（Glucose Oxidase, GOX）在磁性壳聚糖纳米颗粒（Magnetic Chitosan Nanoparticles, MCNP）上的固定化效率的影响、pH对酶活性的作用，以及固定于MCNP上的酶的动力学特性变化。本研究采用交联键与希夫碱共价结合的方式将GOX固定于MCNP。当壳聚糖用量为0.3 g时，对应样品的固定化效率最高，可达41.30%。通过扫描电子显微镜（Scanning Electron Microscopy, SEM）对纳米颗粒的形貌进行了表征分析。借助傅里叶变换红外光谱（Fourier Transform Infrared, FTIR）验证了GOX在磁性纳米颗粒上的成功固定。pH对酶活性的影响在固定化酶（immobilized enzyme, IE）与游离酶（free enzyme, FE）中表现出相似的规律。对固定化酶与游离酶的动力学参数评估结果显示，其有效因子为0.45。综上可得出结论：添加0.3 g壳聚糖制备的磁性纳米颗粒可作为GOX固定化的适宜载体。