Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
Bioresour Technol. 2012 Jan;103(1):273-8. doi: 10.1016/j.biortech.2011.09.118. Epub 2011 Oct 2.
Silver nanoparticles (AgNPs) were obtained by solar irradiation of cell-free extracts of Bacillusamyloliquefaciens and AgNO3. Light intensity, extract concentration, and NaCl addition influenced the synthesis of AgNPs. Under optimized conditions (solar intensity 70,000 lx, extract concentration 3 mg/mL, and NaCl content 2 mM), 98.23±0.06% of the Ag+ (1 mM) was reduced to AgNPs within 80 min, and the ζ-potential of AgNPs reached -70.84±0.66 mV. TEM (Transmission electron microscopy) and XRD (X-ray diffraction) analysis confirmed that circular and triangular crystalline AgNPs with mean diameter of 14.6 nm were synthesized. Since heat-inactivated extracts also mediated the formation of AgNPs, enzymatic reactions are likely not involved in AgNPs formation. A high absolute ζ-potential value of the AgNPs, possibly caused by interaction with proteins likely explains the high stability of AgNPs suspensions. AgNPs showed antimicrobial activity against Bacillussubtilis and Escherichiacoli in liquid and solid medium.
银纳米粒子（AgNPs）是通过太阳光照射解淀粉芽孢杆菌的无细胞提取物和 AgNO3 获得的。光照强度、提取物浓度和 NaCl 添加量影响 AgNPs 的合成。在优化条件下（太阳光强度 70,000 lx、提取物浓度 3 mg/mL 和 NaCl 含量 2 mM），1 mM 的 Ag+ 在 80 分钟内被还原为 AgNPs 的效率达到 98.23±0.06%，AgNPs 的 ζ-电位达到-70.84±0.66 mV。TEM（透射电子显微镜）和 XRD（X 射线衍射）分析证实，合成了平均直径为 14.6 nm 的圆形和三角形的结晶 AgNPs。由于热失活的提取物也介导了 AgNPs 的形成，因此可能不涉及酶反应。AgNPs 悬浮液的高稳定性可能归因于其高绝对值的 ζ-电位，这可能是由于与蛋白质的相互作用所致。AgNPs 在液体和固体培养基中对枯草芽孢杆菌和大肠杆菌表现出抗菌活性。
