Abstract Recently, rapid progress has been made in the utilization of microbes for green synthesis of metal nanoparticles. We found that the cell-free supernatant of the extremophile Deinococcus wulumuqiensis R12 contains silver nanoparticles (AgNPs) when grown in media with different concentrations of AgNO3. The microbially synthesized AgNPs were then systematically characterized by UV/Vis spectroscopy (UV/Vis), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), dynamic light scattering (DLS) and zeta potential measurements. The microbial AgNPs had an absorption peak at 430 nm and had a face-centered cubic structure. They were spherical with a uniform size of 5–16 nm, which was smaller than most reported AgNPs. The mechanism of nanoparticle synthesis by D. wulumuqiensis R12 was then briefly investigated. A previously unknown NADPH-dependent oxidoreductase of 28.29 kDa was identified, which might play the main role in the biosynthesis of AgNPs by strain R12. The concentration of the oxidoreductase in the supernatant increased 4-fold after the addition of AgNO3. Furthermore, the addition of NADPH significantly improved the production of AgNPs.

中文翻译：

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抗辐射奇异球菌乌鲁木齐R12制备胞外银纳米粒子及其机理展望

摘要 近年来，利用微生物绿色合成金属纳米颗粒取得了快速进展。我们发现极端微生物 Deinococcus wulumuqiensis R12 的无细胞上清液在含有不同浓度 AgNO3 的培养基中生长时含有银纳米粒子 (AgNPs)。然后通过紫外/可见光谱 (UV/Vis)、X 射线衍射 (XRD)、傅里叶变换红外光谱 (FTIR)、扫描电子显微镜 (SEM)、透射电子显微镜 (TEM)、能量-色散光谱 (EDS)、动态光散射 (DLS) 和 zeta 电位测量。微生物 AgNPs 在 430 nm 处有一个吸收峰，并具有面心立方结构。它们是球形的，尺寸均匀，为 5-16 nm，比大多数报道的 AgNP 小。然后简要研究了 D. wulumuqiensis R12 合成纳米颗粒的机制。鉴定了一种以前未知的 28.29 kDa 的 NADPH 依赖性氧化还原酶，它可能在菌株 R12 的 AgNPs 生物合成中起主要作用。添加 AgNO3 后，上清液中氧化还原酶的浓度增加了 4 倍。此外，添加 NADPH 显着提高了 AgNPs 的产量。