摘要
Magnetic nanoparticles（Fe3O4） were synthesized by co-precipitating Fe^2＋ and Fe^3＋ ions in an ammonia solution and treating under hydrothermal conditions.Cellulase was immobilized onto Fe3O4 magnetic nanoparticles via glutaraldehyde activation.Using response surface methodology and Box-Behnken design,the variables such as magnetic nanoparticle concentration,glutaraldehyde concentration,enzyme concentration,and cross linking time were optimized.The Box-Behnken design analysis showed a reasonable adjustment of the quadratic model with the experimental data.Statistical contour plots were generated to evaluate the changes in the response surface and to understand the relationship between the nanoparticles and the enzyme activity.Scanning electron microscopy,X-ray diffraction analysis,and Fourier transform infrared spectroscopy were studied to characterize size,structure,morphology,and binding of enzyme onto the nanoparticles.The stability and activity of the bound cellulase was analyzed using various parameters including pH,temperature,reusability,and storage stability.The immobilized cellulase was compared with free cellulase and it shows enhanced stability and activity.
在氨水溶液中进行Fe^(+2)和Fe^(+3)离子共沉淀并水热处理后制得磁性纳米颗粒Fe_3O_4,通过戊二醛活化将纤维素酶固定于其上.采用基于响应面法的Box-Behnken法(BBD)优化了制备条件,如磁性纳米颗粒浓度、戊二醛浓度、酶浓度和交联时间.BBD分析结果表明,用实验数据可合理调节二次模型.利用生成的基于统计数据的等高线评价了响应面的变化,以理解纳米颗粒和酶活性之间的关系.运用扫描电镜、X射线衍射和红外光谱表征了纳米颗粒上酶的尺寸、结构、形貌和结合情况.采用诸如pH值、温度、重复使用性和存储能力分析了固定化纤维素酶的活性和稳定性.发现固定后的纤维素酶表现出更好的稳定性和活性.
