Insights into the uranium(VI) speciation with Pseudomonas fluorescens on a molecular level
Insights into the uranium(VI) speciation with Pseudomonas fluorescens on a molecular level
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DOI：
10.1039/c2dt31080e
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发表时间：
2012-01-01
影响因子：
4
通讯作者：
Bernhard, Gert
中科院分区：
文献类型：
--
作者：
Luetke, Laura;Moll, Henry;Bernhard, Gert
微生物有很大的潜力，结合，从而在环境中运输锕系元素。因此，在评估计划处置库的安全性时，必须调查指定核废物处置场的土著微生物与可溶性放线菌离子的相互作用机制。本文介绍了pH值依赖的吸附U（VI）到荧光假单胞菌分离的花岗岩岩石含水层在Aspo硬岩实验室，瑞典的结果。为了在分子水平上表征U（VI）相互作用，采用电位滴定结合时间分辨激光诱导荧光光谱（TRLFS）。因此，本文是极少数提供与细胞表面官能团络合的U（VI）稳定常数的来源之一。此外，还研究了不同pH条件下细菌介导的无机磷酸盐释放对[U（VI）]的依赖性，以判断磷酸盐释放对U（VI）动员的影响。结果表明，在酸性pH范围内，U（VI）主要通过质子化的磷酰基和羧基位点与细胞结合。通过羧基的络合可以在宽的pH范围内观察到高达约pH 7。在中性pH下，完全去质子化的磷酰基主要负责U（VI）结合。荧光假单胞菌能以较高的热力学稳定性与U（VI）结合。
Microorganisms have great potential to bind and thus transport actinides in the environment. Thus microbes indigenous to designated nuclear waste disposal sites have to be investigated regarding their interaction mechanisms with soluble actinyl ions when assessing the safety of a planned repository. This paper presents results on the pH-dependent sorption of U(VI) onto Pseudomonas fluorescens isolated from the granitic rock aquifers at Aspo Hard Rock Laboratory, Sweden. To characterize the U(VI) interaction on a molecular level, potentiometric titration in combination with time-resolved laser-induced fluorescence spectroscopy (TRLFS) were applied. This paper as a result is one of the very few sources which provide stability constants of U(VI) complexed by cell surface functional groups. In addition the bacteria-mediated liberation of inorganic phosphate in dependence on [U(VI)] at different pHs was studied to judge the influence of phosphate release on U(VI) mobilization. The results demonstrate that in the acidic pH range U(VI) is bound by the cells mainly via protonated phosphoryl and carboxylic sites. The complexation by carboxylic groups can be observed over a wide pH range up to around pH 7. At neutral pH fully deprotonated phosphoryl groups are mainly responsible for U(VI) binding. U(VI) can be bound by P. fluorescens with relatively high thermodynamic stability.