Sulfur-mediated electron shuttling during bacterial iron reduction
Sulfur-mediated electron shuttling during bacterial iron reduction
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DOI：
10.1126/science.1252066
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发表时间：
2014-05-30
期刊：
影响因子：
56.9
通讯作者：
Kemner, Kenneth M.
中科院分区：
文献类型：
--
作者：
Flynn, Theodore M.;O'Loughlin, Edward J.;Kemner, Kenneth M.
微生物还原Fe（III）是缺氧含水层中重要的生态地球化学过程。根据地下水的pH值，异化金属还原细菌也可以呼吸替代电子受体来生存，包括元素硫（S度）。为了了解铁/硫循环在碱性条件下的相互作用，我们结合了热力学地球化学模拟与生物反应器实验使用希瓦氏菌oneidensis MR-1。在此条件下，S. oneidensis可以酶促还原S度，但不还原针铁矿（α-FeOOH）。HS-产生的产物随后将针铁矿非生物还原。由于在许多含水层的碱性条件下，Fe（III）的还原，因此可以通过S度介导的电子穿梭途径进行。
Microbial reduction of ferric iron [Fe(III)] is an important biogeochemical process in anoxic aquifers. Depending on groundwater pH, dissimilatory metal-reducing bacteria can also respire alternative electron acceptors to survive, including elemental sulfur (S degrees). To understand the interplay of Fe/S cycling under alkaline conditions, we combined thermodynamic geochemical modeling with bioreactor experiments using Shewanella oneidensis MR-1. Under these conditions, S. oneidensis can enzymatically reduce S degrees but not goethite (alpha-FeOOH). The HS- produced subsequently reduces goethite abiotically. Because of the prevalence of alkaline conditions in many aquifers, Fe(III) reduction may thus proceed via S degrees-mediated electron-shuttling pathways.