Mishra Abhijeet, Sardar Meryam
Department of Biosciences, Jamia Millia Islamia, New Delhi 110025, India.
Department of Biosciences, Jamia Millia Islamia, New Delhi 110025, India.
Int J Biol Macromol. 2015;77:105-13. doi: 10.1016/j.ijbiomac.2015.03.014. Epub 2015 Mar 19.
In the present study, we report in vitro synthesis of silver and gold nanoparticles (NPs) using cellulase enzyme in a single step reaction. Synthesized nanoparticles were characterized by UV-VIS spectroscopy, Dynamic Light Spectroscopy (DLS), Transmission Electron Microscopy (TEM), Energy-dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), Circular Dichroism (CD) and Fourier Transform Infrared Spectroscopy (FTIR). UV-visible studies shows absorption band at 415nm and 520nm for silver and gold NPs respectively due to surface plasmon resonance. Sizes of NPs as shown by TEM are 5-25nm for silver and 5-20nm for gold. XRD peaks confirmed about phase purity and crystallinity of silver and gold NPs. FTIR data shows presence of amide I peak on both the NPs. The cellulase assisted synthesized NPs were further exploited as immobilization matrix for cellulase enzyme. Thermal stability analysis reveals that the immobilized cellulase on synthesized NPs retained 77-80% activity as compared to free enzyme. While reusability data suggests immobilized cellulase can be efficiently used up to sixth cycles with minimum loss of enzyme activity. The secondary structural analysis of cellulase enzyme during the synthesis of NPs and also after immobilization of cellulase on these NPs was carried out by CD spectroscopy.
在本研究中，我们报告了在一步反应中使用纤维素酶体外合成银和金纳米颗粒（NPs）。通过紫外可见光谱、动态光散射（DLS）、透射电子显微镜（TEM）、能量色散X射线光谱（EDX）、X射线衍射（XRD）、圆二色性（CD）和傅里叶变换红外光谱（FTIR）对合成的纳米颗粒进行了表征。紫外可见研究表明，由于表面等离子体共振，银和金纳米颗粒分别在415nm和520nm处有吸收带。TEM显示银纳米颗粒的尺寸为5-25nm，金纳米颗粒的尺寸为5-20nm。XRD峰证实了银和金纳米颗粒的相纯度和结晶度。FTIR数据显示两种纳米颗粒上都存在酰胺I峰。纤维素酶辅助合成的纳米颗粒进一步被用作纤维素酶的固定化基质。热稳定性分析表明，与游离酶相比，固定在合成纳米颗粒上的纤维素酶保留了77-80%的活性。而可重复使用性数据表明，固定化纤维素酶可以有效地使用到第六个循环，酶活性损失最小。通过CD光谱对纳米颗粒合成过程中以及纤维素酶固定在这些纳米颗粒上之后的纤维素酶二级结构进行了分析。
