Multiple lines of evidence identify U(V) as a key intermediate during U(VI) reduction by Shewanella oneidensis MR1.
Multiple lines of evidence identify U(V) as a key intermediate during U(VI) reduction by Shewanella oneidensis MR1.
复制标题
DOI：
10.1021/acs.est.9b05285
复制
发表时间：
2020-01
影响因子：
11.4
通讯作者：
Gianni F. Vettese;K. Morris;L. Natrajan;S. Shaw;T. Vitova;J. Galanzew;Debbie L. Jones;J. Lloyd
中科院分区：
文献类型：
--
作者：
Gianni F. Vettese;K. Morris;L. Natrajan;S. Shaw;T. Vitova;J. Galanzew;Debbie L. Jones;J. Lloyd
作为许多放射性废物中以质量计的主要放射性核素，铀在受污染环境中的迁移性控制受到高度关注。U的形态形成可以通过微生物的相互作用来控制，金属还原细菌能够将可溶的U(VI)还原为不可溶的U(IV)，为从受污染的地下水中去除U提供了一种方法。虽然微生物还原铀(VI)被广泛报道，但关于U(VI)转化为难溶U(IV)相的机制(S)却知之甚少。通过结合一系列分析，包括发光，U M4边HERFD-XANES和U L3边XANES/EXAFS，我们证明了模式Fe(III)还原细菌Shewanella onedensis MR1对U(VI)的微生物还原通过单电子转移形成五价U(V)中间体，该中间体不成比例地生成U(VI)和U(IV)。此外，我们已经确定了还原后固相中存在大量的U(V)，这意味着U(V)可以稳定长达120.5小时。
As the dominant radionuclide by mass in many radioactive wastes, the control of uranium mobility in contaminated environments is of high concern. U speciation can be governed by microbial interactions, whereby metal-reducing bacteria are able to reduce soluble U(VI) to insoluble U(IV), providing a method for removal of U from contaminated groundwater. Although microbial U(VI) reduction is widely reported, the mechanism(s) for the transformation of U(VI) to poorly soluble U(IV) phases are poorly understood. By combining a suite of analyses, including luminescence, U M4-edge HERFD-XANES and U L3-edge XANES/EXAFS we show that the microbial reduction of U(VI) by the model Fe(III)-reducing bacterium, Shewanella oneidensis MR1, proceeds via a single electron transfer to form a pentavalent U(V) intermediate which disproportionates to form U(VI) and U(IV). Furthermore, we have identified significant U(V) present in post reduction solid phases, implying that U(V) may be stabilised for up to 120.5 hours.