Enrichment of Microbial Electrolysis Cell Biocathodes from Sediment Microbial Fuel Cell Bioanodes
Enrichment of Microbial Electrolysis Cell Biocathodes from Sediment Microbial Fuel Cell Bioanodes
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DOI：
10.1128/aem.00480-12
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发表时间：
2012-08-01
影响因子：
4.4
通讯作者：
Logan, Bruce E.
中科院分区：
文献类型：
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作者：
Pisciotta, John M.;Zaybak, Zehra;Logan, Bruce E.
在沉淀型微生物燃料电池(SMFC)中，首先用两种不同的海洋沉积物将石墨纤维刷状电极作为阳极，然后在两室生物电化学系统(BESS)中将其作为阴极进行电反转，从而制备出接受电子(电营养)的生物电极。在缺乏有机能源的最小介质中，电子消耗发生在设定电位-439 mV和-539 mV(与标准氢电极的电位相比)，而不是-339 mV。在这些不同电位下的结果与单独的线性扫描伏安法(LSV)扫描相一致，表明增强的活动(电流消耗)仅在-400 mV以下。未在设定电位下驯化的MFC生物阳极产生接受电子(电营养)的生物电极，但在设定电位(+11 mV)下运行的生物阳极不产生。从阴极顶空隙中去除CO，表明电营养生物节肢动物是自养的。氢气的产生，随后一个样品中氢气和甲烷产量的损失，表明氢遗传营养产甲烷作用。生物催化室中有大量的微生物生长，这从浊度的增加和阴极表面微生物的存在就是明证。对16S rRNA基因的克隆文库分析表明，16S rRNA基因的显著序列与利莫氏真细菌(丁酸杆菌)、硫化弧菌最相似。A2、暗色红球菌和暗色双歧杆菌。在新BESS中，将悬浮液转移到由石墨板、碳棒或碳刷制成的无菌阴极上，4天后电流增加，表明这些微生物群落在各种阴极基质上生长。本报告提供了一种简单而有效的方法，通过使用sMFC而不需要设置电位，然后使用比-400 mV更负的电位来丰富自养电营养化。
Electron-accepting (electrotrophic) biocathodes were produced by first enriching graphite fiber brush electrodes as the anodes in sediment-type microbial fuel cells (sMFCs) using two different marine sediments and then electrically inverting the anodes to function as cathodes in two-chamber bioelectrochemical systems (BESs). Electron consumption occurred at set potentials of -439 mV and -539 mV (versus the potential of a standard hydrogen electrode) but not at -339 mV in minimal media lacking organic sources of energy. Results at these different potentials were consistent with separate linear sweep voltammetry (LSV) scans that indicated enhanced activity (current consumption) below only ca. -400 mV. MFC bioanodes not originally acclimated at a set potential produced electron-accepting (electrotrophic) biocathodes, but bioanodes operated at a set potential (+11 mV) did not. CO, was removed from cathode headspace, indicating that the electrotrophic biocathodes were autotrophic. Hydrogen gas generation, followed by loss of hydrogen gas and methane production in one sample, suggested hydrogenotrophic methanogenesis. There was abundant microbial growth in the biocathode chamber, as evidenced by an increase in turbidity and the presence of microorganisms on the cathode surface. Clone library analysis of 16S rRNA genes indicated prominent sequences most similar to those of Eubacterium limosum (Butyribacterium methylotrophicum), Desulfovibrio sp. A2, Rhodococcus opacus, and Gemmata obscuriglobus. Transfer of the suspension to sterile cathodes made of graphite plates, carbon rods, or carbon brushes in new BESs resulted in enhanced current after 4 days, demonstrating growth by these microbial communities on a variety of cathode substrates. This report provides a simple and effective method for enriching autotrophic electrotrophs by the use of sMFCs without the need for set potentials, followed by the use of potentials more negative than -400 mV.