希瓦氏菌Shewallena oneidensis MR-1合成硒纳米棒

Biosynthesis of selemium nanobars by Shewallena oneidensis MR-1

摘要:

摘要:【目的】探索采用希瓦氏菌合成硒(Se)纳米棒，并阐明合成底物Se(IV)的浓度与细菌培养时间对生物合成的影响。【方法】将希瓦氏菌Shewallena oneidensis MR-1 接种至Luria-Bertani(LB)液体培养基，分别以Se(IV)浓度0.1、1、10和100 mmol/L的Na2 SO3作为电子受体，厌氧培养并绘制生长曲线。再将希瓦氏菌接种到含最适Se( IV)浓度的LB 培养基中，在厌氧培养后第24和72 h离心获取沉淀。采用扫描电镜、X射线能谱和X射线衍射对沉淀进行分析。【结果】在Se(IV)浓度1 mmol/L的培养基中培养24 h形成的纳米棒沉淀截面直径约80 nm，长度2－3 μm。而培养72 h形成的沉淀较大，超出纳米物质范畴。采用X射线能谱和X射线衍射确定纳米棒组成为单质Se。【结论】本研究为生物合成Se纳米棒提供了一种可行的方法。希瓦氏菌最适宜在1 mmol/L Se(IV)浓度下以及在对数生长期大量合成Se纳米棒，具有潜在应用价值。

Abstract:

Abstract:［Objective］ We used Shewallena oneidensis MR-1 to produce selemium (Se) nanobars and studied the influence of Se(IV) concentrations and incubation time on nanobars production.［Methods］We incubated Shewallena oneidensis MR-1 under anaerobic condition with Luria-Bertani (LB) liquid medium containing 0.1，1.0，10.0 or 100.0 mmol/L Se(IV) in Na2 SeO3，to determine the optimal Se(IV) concentration for bacterial growth．Then，we incubated Shewallena oneidensis MR-1 with the optimal Se (IV) concentration and collected deposits 24 and 72 h after anearobic incubation．We used scanning electron microscopy，energy-dispersive X-ray and X-ray diffraction to analyse the deposits.［Results］The cross sectional diameter and length of deposits that were produced by Shewallena oneidensis MR-1 after 24 h incubation with 1 mmol/L Se(IV) was around 80 nm and 2-3 μm，respectively． However，the deposits after 72 h incubation exceeded the size limit of nano material． Furthermore，the energy-dispersive X-ray and the X-ray diffraction spectroscopy confirmed that the deposits were elemental Se.［Conclusion］This study provides a viable method for the biosynthesis of Se nanobar. Shewallena oneidensis MR-1 can produce a large number of Se nanobars at exponential phase under 0.1 mmol /L Se(IV).