Microbial Iron Redox Cycling in a Circumneutral-pH Groundwater Seep
Microbial Iron Redox Cycling in a Circumneutral-pH Groundwater Seep
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DOI：
10.1128/aem.01817-08
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发表时间：
2009-01-15
影响因子：
4.4
通讯作者：
Roden, Eric E.
中科院分区：
文献类型：
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作者：
Bloethe, Marco;Roden, Eric E.
研究了亚拉巴马中北部一个环境中性-pH地下水渗漏中微生物介导的铁（Fe）氧化还原循环的潜力。在缺氧条件下，用乙酸-乳酸盐或H-2作为电子供体孵育新鲜收集的渗漏材料，揭示了快速Fe（III）氧化物还原的潜力（约100%）。700至2，000 μ mol/L（-1）天（-1））。Fe（III）以较低但显着的速率减少发生在未经修正的对照组（约。300 μ mol/L（-1）天（-1））。基于培养物的计数（最大可能数[MPN]）显示了大量（10（2）至10（6）个细胞ml（-1））的有机碳和H-2氧化异化Fe（III）还原微生物。获得了三种具有通过异化或发酵代谢还原Fe（III）氧化物的能力的分离物（Gephylla sp.菌株IST-3、Shewanella sp.菌株IST-21和Bacillus sp.菌株IST-38）。MPN分析还显示存在微需氧Fe（II）氧化微生物（10（3）至10（5）个细胞ml（-1））。铁渗漏的16 S rRNA基因文库主要由Betaproteobacteria的代表，包括Gallionella，Leptothrix和Comamonas物种。好氧Fe（II）氧化丛毛单胞菌菌株IST-3被分离。该微生物的16 S rRNA基因序列与β-变形杆菌睾丸酮丛毛单胞菌（M11224）的模式菌株100%相似。模式菌株的测试显示没有Fe（II）氧化。总的来说，我们的研究结果表明，活跃的微生物铁氧化还原循环发生在这个栖息地和支持以前的概念模型，如何微生物铁的氧化和还原可以耦合在地表和地下沉积环境。
The potential for microbially mediated redox cycling of iron (Fe) in a circumneutral-pH groundwater seep in north central Alabama was studied. Incubation of freshly collected seep material under anoxic conditions with acetate-lactate or H-2 as an electron donor revealed the potential for rapid Fe(III) oxide reduction (ca. 700 to 2,000 mu mol liter(-1) day(-1)). Fe(III) reduction at lower but significant rates took place in unamended controls (ca. 300 mu mol liter(-1) day(-1)). Culture-based enumerations (most probable numbers [ MPNs]) revealed significant numbers (10(2) to 10(6) cells ml(-1)) of organic carbon- and H-2-oxidizing dissimilatory Fe(III)-reducing microorganisms. Three isolates with the ability to reduce Fe(III) oxides by dissimilatory or fermentative metabolism were obtained (Geobacter sp. strain IST-3, Shewanella sp. strain IST-21, and Bacillus sp. strain IST-38). MPN analysis also revealed the presence of microaerophilic Fe(II)-oxidizing microorganisms (10(3) to 10(5) cells ml(-1)). A 16S rRNA gene library from the iron seep was dominated by representatives of the Betaproteobacteria including Gallionella, Leptothrix, and Comamonas species. Aerobic Fe(II)-oxidizing Comamonas sp. strain IST-3 was isolated. The 16S rRNA gene sequence of this organism is 100% similar to the type strain of the betaproteobacterium Comamonas testosteroni (M11224). Testing of the type strain showed no Fe(II) oxidation. Collectively our results suggest that active microbial Fe redox cycling occurred within this habitat and support previous conceptual models for how microbial Fe oxidation and reduction can be coupled in surface and subsurface sedimentary environments.