Enrichment of members of the family Geobacteraceae associated with stimulation of dissimilatory metal reduction in uranium-contaminated aquifer sediments
Enrichment of members of the family Geobacteraceae associated with stimulation of dissimilatory metal reduction in uranium-contaminated aquifer sediments
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DOI：
10.1128/aem.68.5.2300-2306.2002
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发表时间：
2002-05-01
影响因子：
4.4
通讯作者：
Lovley, DR
中科院分区：
文献类型：
--
作者：
Holmes, DE;Finneran, KT;Lovley, DR
刺激微生物还原可溶性U（VI）为不溶性U（IV）显示出作为在铀污染的地下环境中固定铀的策略的希望。为了了解更多关于哪些微生物可能参与U（VI）原位还原，在微生物群落的变化时，U（VI）还原刺激与乙酸盐的加入进行了监测，在沉积物中的三个不同的铀污染地点的圣胡安河在新墨西哥州希普洛克，洪泛区。在所有三个沉积物中，U（VI）的减少是伴随着并发Fe（III）的减少和显着富集的微生物在家庭Geobacteraceae，这是已知的U（VI）和Fe（III）还原微生物。当U（VI）还原和Fe（III）还原接近完成时，土杆菌科占约。40%的16 S核糖体DNA（rDNA）序列从沉积物中回收的细菌PCR引物，而土杆菌科占不到5%的16 S rDNA序列在对照沉积物中，没有修改与乙酸，其中U（VI）和Fe（III）的减少没有刺激。这些土杆菌科序列的55%和65%之间是最相似的序列从脱硫单胞菌物种，其余的是最密切相关的Geobacteria物种。最大可能数PCR和TaqMan分析的Geobacteraceae序列的定量分析表明，从2到4个数量级的增加，在过程中的U（VI）和Fe（III）的乙酸盐修正的沉积物从三个网站。在对照沉积物中没有观察到土杆菌科序列的增加。在优势的土杆菌科序列相比，没有序列相关的其他已知的Fe（III）-还原微生物在沉积物中检测到。这些结果与越来越多的研究相比，已经证明，Geobacteraceae的地下环境中，Fe（III）还原是一个重要的过程中的多样性的微生物群落的重要组成部分。结合这些结果与发现，U（VI）还原发生在Fe（III）还原和硫酸盐还原之前，表明Geobacteraceae将负责大部分的Fe（III）和U（VI）的还原在这些沉积物中的铀生物修复过程中。
Stimulating microbial reduction of soluble U(VI) to insoluble U(IV) shows promise as a strategy for immobilizing uranium in uranium-contaminated subsurface environments. In order to learn more about which microorganisms might be involved in U(VI) reduction in situ, the changes in the microbial community when U(VI) reduction was stimulated with the addition of acetate were monitored in sediments from three different uranium-contaminated sites in the floodplain of the San Juan River in Shiprock, N.Mex. In all three sediments U(VI) reduction was accompanied by concurrent Fe(III) reduction and a dramatic enrichment of microorganisms in the family Geobacteraceae, which are known U(VI)- and Fe (III)-reducing microorganisms. At the point when U(VI) reduction and Fe(III) reduction were nearing completion, Geobacteraceae accounted for ca. 40% of the 16S ribosomal DNA (rDNA) sequences recovered from the sediments with bacterial PCR primers, whereas Geobacteraceae accounted for fewer than 5% of the 16S rDNA sequences in control sediments that were not amended with acetate and in which U(VI) and Fe(III) reduction were not stimulated. Between 55 and 65% of these Geobacteraceae sequences were most similar to sequences from Desulfuromonas species, with the remainder being most closely related to Geobacter species. Quantitative analysis of Geobacteraceae sequences with most-probable-number PCR and TaqMan analyses indicated that the number of Geobacteraceae sequences increased from 2 to 4 orders of magnitude over the course of U(VI) and Fe(III) reduction in the acetate-amended sediments from the three sites. No increase in Geobacteraceae sequences was observed in control sediments. In contrast to the predominance of Geobacteraceae sequences, no sequences related to other known Fe (III) -reducing microorganisms were detected in sediments. These results compare favorably with an increasing number of studies which have demonstrated that Geobacteraceae are important components of the microbial community in a diversity of subsurface environments in which Fe(III) reduction is an important process. The combination of these results with the finding that U(VI) reduction takes place during Fe(III) reduction and prior to sulfate reduction suggests that Geobacteraceae will be responsible for much of the Fe(III) and U(VI) reduction during uranium bioremediation in these sediments.