Electrochemical characterization of direct electron uptake in electrical microbially influenced corrosion of iron by the lithoautotrophic SRB Desulfopila corrodens strain IS4
Electrochemical characterization of direct electron uptake in electrical microbially influenced corrosion of iron by the lithoautotrophic SRB Desulfopila corrodens strain IS4
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DOI：
10.1016/j.electacta.2015.03.184
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发表时间：
2015-06-10
影响因子：
6.6
通讯作者：
Mayrhofer, Karl J. J.
中科院分区：
文献类型：
--
作者：
Beese-Vasbender, Pascal F.;Nayak, Simantini;Mayrhofer, Karl J. J.
缺氧环境中铁基础设施的腐蚀通常归因于硫酸盐还原菌（SRB）的代谢活动，其可以影响金属表面上的电化学过程。本研究的特点是电子转移过程中的电极/微生物界面的专门的石自养硫酸盐还原菌Desulfopila corrodens菌株IS 4，能够采取电子直接从元素铁，从而导致严重的腐蚀。电化学分析的高腐蚀性SRB进行在生物电化学电池与人工海水缺氧条件下，辅以红外光谱电化学分析和环境扫描电镜观察。为了提供对电子转移过程的清楚了解，平行分析了无菌对照和非腐蚀性氢营养对照菌株。值得注意的是，D.腐蚀菌菌株IS 4不限于铁作为微生物代谢的唯一电子供体，而是也在石墨和掺杂的锗阴极上进行。因此，电子吸收机制的明确的电化学分析是可能的，因为在铁电极上通常观察到的腐蚀沉淀物在其他阴极材料上都不存在。在中性条件下，在不存在人工电子介体的情况下，在-0.4V vs. SHE的电位下实现直接电子转移。电化学和红外光谱电化学分析表明，C型细胞色素作为与外膜相关的氧化还原活性组分参与了D.腐蚀菌株IS 4。(C)2015爱思唯尔有限公司版权所有。
Corrosion of iron infrastructure in anoxic environments is commonly ascribed to the metabolic activity of sulfate-reducing bacteria (SRB), which can influence electrochemical processes on the metallic surface. The present study characterizes electron transfer processes at the electrode/microorganism interface of the specialized lithoautotrophic SRB Desulfopila corrodens strain IS4 that is capable of taking up electrons directly from elemental iron, thereby leading to severe corrosion. Electrochemical analysis of the highly corrosive SRB is performed in bio-electrochemical cells operated with artificial seawater under anoxic conditions, complemented by infrared spectroelectrochemical analysis and environmental SEM observations. In order to provide clear insights into electron transfer processes, sterile controls and a non-corrosive hydrogenotrophic control strain are analyzed in parallel. Remarkably, the electron uptake from electrodes by D. corrodens strain IS4 is not restricted to iron serving as the sole electron donor for the microbial metabolism, but instead proceeds also on graphite and doped germanium cathodes. Consequently, a well-defined electrochemical analysis of the electron uptake mechanism is possible, since corrosion precipitates typically observed on iron electrodes are absent on both of the other cathode materials. Direct electron transfer in the absence of artificial electron mediators is achieved at a potential of -0.4 V vs. SHE under neutral conditions. Electrochemical and infrared spectroelectrochemical analysis indicated c-type cytochromes as the redox active components associated with the outer membrane to be involved in the direct electron uptake from reduced surfaces by D. corrodens strain IS4. (C) 2015 Elsevier Ltd. All rights reserved.