Uranium isotopic fractionation factors during U(VI) reduction by bacterial isolates
Uranium isotopic fractionation factors during U(VI) reduction by bacterial isolates
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DOI：
10.1016/j.gca.2014.02.041
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发表时间：
2014-07-01
影响因子：
5
通讯作者：
Loeffler, Frank E.
中科院分区：
文献类型：
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作者：
Basu, Anirban;Sanford, Robert A.;Loeffler, Frank E.
我们实验确定了由金属还原细菌分离物引起的U（VI）还原引起的铀同位素分馏的大小。我们的研究结果表明，微生物U（VI）还原诱导同位素分馏;较重的同位素（即，U-238）分配到固体U（IV）产物中。铀-238/铀-235的同位素分馏程度（以α = 1000份/千 *（α-1）表示）分别为0.68份/千+/- 0.05份/千和0.99份/千+/- 0.12份/千（对于还原硫锗藻菌株PCA和菌株IFRC-N）。脱卤厌氧黏菌菌株FRC-W、菌株FRC-R5（一种新的希瓦氏菌属分离株）和脱硫杆菌属菌株Viet 1的pH值分别为0.72份/千+/-0.15份/千、0.99份/千+/-0.12份/千，0.96份/千+/- 0.16份/千和0.86份/千+/- 0.06份/千。我们的研究结果表明，获得了类似于1.0份千分之一的最大生物量（类似于10（7）细胞/毫升）和低电子供体浓度（类似于500 μ M）。这些结果提供了由微生物介导的U（VI）还原引起的U-238/U-235位移的初步评估，这是随着U-238/U-235数据越来越多地用作各种地球化学环境中的氧化还原指示剂所需要的。(C)2014爱思唯尔有限公司版权所有。
We experimentally determined the magnitude of uranium isotopic fractionation induced by U(VI) reduction by metal reducing bacterial isolates. Our results indicate that microbial U(VI) reduction induces isotopic fractionation; heavier isotopes (i.e., U-238) partition into the solid U(IV) products. The magnitudes of isotopic fractionation (expressed as epsilon = 1000 parts per thousand * (alpha-1)) for U-238/U-235 were 0.68 parts per thousand +/- 0.05 parts per thousand and 0.99 parts per thousand +/- 0.12 parts per thousand for Geobacter sulfurreducens strain PCA and strain IFRC-N, respectively. The epsilon values for Anaeromyxobacter dehalogenans strain FRC-W, strain FRC-R5, a novel Shewanella isolate, and Desulfitobacterium sp. strain Viet1 were 0.72 parts per thousand +/- 0.15 parts per thousand, 0.99 parts per thousand +/- 0.12 parts per thousand, 0.96 parts per thousand +/- 0.16 parts per thousand and 0.86 parts per thousand +/- 0.06 parts per thousand, respectively. Our results show that the maximum epsilon values of similar to 1.0 parts per thousand were obtained with low biomass (similar to 10(7) cells/mL) and low electron donor concentrations (similar to 500 mu M). These results provide an initial assessment of U-238/U-235 shifts induced by microbially-mediated U(VI) reduction, which is needed as U-238/U-235 data are increasingly applied as redox indicators in various geochemical settings. (C) 2014 Elsevier Ltd. All rights reserved.