Biosynthesis of selemium nanobars by Shewallena oneidensis MR-1

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).