Bioelectrochemical Analyses of the Development of a Thermophilic Biocathode Catalyzing Electromethanogenesis
Bioelectrochemical Analyses of the Development of a Thermophilic Biocathode Catalyzing Electromethanogenesis
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DOI：
10.1021/es5052233
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发表时间：
2015-01-20
影响因子：
11.4
通讯作者：
Kobayashi, Hajime
中科院分区：
文献类型：
--
作者：
Fu, Qian;Kuramochi, Yoshihiro;Kobayashi, Hajime
研究了嗜热微生物作为生物催化剂在甲烷电生成中的应用。单室反应器接种了嗜热菌并在55℃下运行，显示出较高的CH4产率（最大最大值）。1103 mmol m(-2) day(-1)，电流捕获效率>90%，表明嗜热菌作为生物催化剂具有很高的潜力。为了提高电产甲烷活性，将开发的生物阴极转移到双室反应器中，并在-0.5 V vs SHE的平衡电位下运行。在定电位孵育160 h后，生物阴极的CH4产率提高了约6倍，这表明生物阴极的驯化导致了性能的提高。阴极菌群的组成变化表明，驯化过程中选择了与产甲烷菌相关的产甲烷菌、协同菌和产热菌相关的细菌。“驯化”生物阴极的循环伏安法显示阴极催化波增强，中点电位约为-0.35 V vs SHE。此外，该生物阴极还能在-0.35 V vs SHE下催化电甲烷生成。这些结果表明，驯化增强了生物阴极通过直接电子转移催化电产甲烷的能力。本研究为电产甲烷生物电化学系统（BESs）提供了新的技术和基础信息，可推广到其他生物电化学系统。
The use of thermophilic microorganisms as biocatalysts for electromethanogenesis was investigated. Single-chamber reactors inoculated with thermophiles and operated at 55 degrees C showed high CH4 production rates (max. 1103 mmol m(-2) day(-1) at an applied voltage of 0.8 V) with current-capture efficiencies >90%, indicating that thermophiles have high potential as biocatalysts. To improve the electromethanogenic activity, the developed biocathode was transferred to a two-chamber reactor and operated at a poised potential of -0.5 V vs SHE. The CH4 production rates of the biocathode were enhanced approximately 6-fold in 160 h of poised-potential incubation, indicating that the acclimation of the biocathode resulted in performance improvement. Compositional alteration of the cathodic microbiota suggested that a Methanothermobacter-related methanogen and synergistetes- and thermotogae-related bacteria were selected during the acclimation. Cyclic voltammetry of the "acclimated" biocathode showed an augmented cathodic catalytic wave with a midpoint potential at ca. -0.35 V vs SHE. Moreover, the biocathode was able to catalyze electromethanogenesis at -0.35 V vs SHE. These results suggested that the ability of the biocathode to catalyze electromethanogenesis via direct electron transfer was enhanced by the acclimation. This study provides new technological and fundamental information on electromethanogenic bioelectrochemical systems (BESs) that may be extended to other BESs.