Engineering Technology, Biotechnology Program, McMaster University, Hamilton, ON, Canada.
World J Microbiol Biotechnol. 2012 Mar;28(3):1081-6. doi: 10.1007/s11274-011-0906-0. Epub 2011 Oct 4.
Locally isolated strains of a thermoalkalotolerant Streptomyces sp. and Aspergillus fumigatus were used for the in vitro biosynthesis of silver nanoparticles from AgNO(3) solutions. An autolysed cell-free culture filtrate from each strain was used, indicating that the formation mechanism depends on intra-cellular components for both organisms, since culture broths had no significant nanoparticle formation potential. Nanoparticle formation was indicated by a change of the solution from colourless or light brown to dark brown after 24 h or more, and UV-visible spectroscopy and x-ray diffraction analysis confirmed the formation by both organisms. The initial formation kinetics were faster with Aspergillus, but formation continued for a longer period with Streptomyces, resulting in higher concentrations after 48 h. Transmission electron microscope images revealed well dispersed nanoparticles with diameters ranging from 15 to 45 nm from A. fumigatus, while those from Streptomyces sp. had a narrower size distribution of 15-25 nm. The higher productivity and preferred narrower size distribution of Streptomyces, together with its well established industrial use, may make it the preferred choice for further optimization studies.
采用一株嗜热耐碱链霉菌（Streptomyces sp.）和一株烟曲霉（Aspergillus fumigatus）的分离菌株，从 AgNO3 溶液中体外生物合成银纳米粒子。使用了每种菌株的自溶无细胞培养滤液，表明形成机制取决于两种生物的细胞内成分，因为培养基没有显著的纳米粒子形成潜力。纳米粒子的形成是通过 24 小时或更长时间后溶液从无色或浅棕色变为深棕色来指示的，并且通过紫外-可见光谱和 X 射线衍射分析证实了这两种生物的形成。初始形成动力学在烟曲霉中更快，但形成在链霉菌中持续更长时间，导致在 48 小时后浓度更高。透射电子显微镜图像显示，来自烟曲霉的纳米粒子分散良好，直径在 15 至 45 纳米之间，而来自链霉菌的纳米粒子的尺寸分布更窄，为 15-25 纳米。链霉菌具有更高的生产力和更倾向于较窄的尺寸分布，以及其成熟的工业用途，可能使其成为进一步优化研究的首选。
