Metal reduction by spores of Desulfotomaculum reducens
Metal reduction by spores of Desulfotomaculum reducens
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DOI：
10.1111/j.1462-2920.2009.02003.x
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发表时间：
2009-12-01
影响因子：
5.1
通讯作者：
Bernier-Latmani, Rizlan
中科院分区：
文献类型：
--
作者：
Junier, Pilar;Frutschi, Manon;Bernier-Latmani, Rizlan
铀污染场地的生物修复旨在刺激能够催化可溶性U（VI）还原为溶解度较低的矿物UO 2的微生物的活性。U（VI）还原不一定支持先前研究的细菌的生长，但它通常涉及活的营养细胞和适当的电子供体的存在。我们的特点是U（VI）还原硫酸盐还原细菌还原脱硫肠状菌菌株MI-1生长发酵丙酮酸，并观察到孢子能够U（VI）还原。氢气-丙酮酸发酵的产物-而不是丙酮酸，作为电子供体。该过程需要使用过的生长培养基，这表明细胞产生的未知因子是还原所必需的。用过的培养基超滤，然后通过U（VI）还原试验表明，该因子的分子大小低于3 kDa。预减少用过的培养基显示短期U（VI）还原活性，这表明丢失的因素可能是一个电子穿梭，但无论是蒽醌-2，6-二磺酸，也没有核黄素抢救孢子在新鲜培养基中的活性。D. reducens也减少铁（III）-柠檬酸盐在实验条件下类似的U（VI）还原。这是第一次报告的细菌能够减少金属，而在孢子化状态，并强调了新的性质的机制，金属还原菌株MI-1。
P>The bioremediation of uranium-contaminated sites is designed to stimulate the activity of microorganisms able to catalyze the reduction of soluble U(VI) to the less soluble mineral UO2. U(VI) reduction does not necessarily support growth in previously studied bacteria, but it typically involves viable vegetative cells and the presence of an appropriate electron donor. We characterized U(VI) reduction by the sulfate-reducing bacterium Desulfotomaculum reducens strain MI-1 grown fermentatively on pyruvate and observed that spores were capable of U(VI) reduction. Hydrogen gas - a product of pyruvate fermentation - rather than pyruvate, served as the electron donor. The presence of spent growth medium was required for the process, suggesting that an unknown factor produced by the cells was necessary for reduction. Ultrafiltration of the spent medium followed by U(VI) reduction assays revealed that the factor's molecular size was below 3 kDa. Pre-reduced spent medium displayed short-term U(VI) reduction activity, suggesting that the missing factor may be an electron shuttle, but neither anthraquinone-2,6-disulfonic acid nor riboflavin rescued spore activity in fresh medium. Spores of D. reducens also reduced Fe(III)-citrate under experimental conditions similar to those for U(VI) reduction. This is the first report of a bacterium able to reduce metals while in a sporulated state and underscores the novel nature of the mechanism of metal reduction by strain MI-1.