Bioelectrochemical systems (BESs) are engineered systems that utilize electrochemical interactions between electrochemically active bacteria (EAB) and electrodes. BESs have attracted considerable attention for their utility in biotechnological processes. In a BES, hydrogen is generated by the reduction of water on low-potential cathode electrodes. However, limited information is available on the effect of hydrogen on the metabolism and growth of EAB and current generation in BESs. Here, we investigated the effect of hydrogen on current generation by a model EAB, Shewanella oneidensis MR-1. We found that this strain utilizes hydrogen as an electron donor for electrode respiration, thereby facilitating current generation and cell growth in the presence of organic substrates. Inner membrane (IM) quinones (i.e., ubiquinone and menaquinone), IM quinone-reactive hydrogenase Hya, and IM-bound quinone reductase CymA are involved in hydrogen-dependent current generation, suggesting that the redox cycling of IM quinones catalyzed by Hya and CymA contributes to the generation of the proton motive force and the synthesis of ATP via F₀F₁-ATPase. These findings indicate that the evolution of hydrogen on the cathode facilitates energy metabolism and growth of hydrogen-utilizing EAB associated with anodes. The results also suggest that hydrogen cycling between cathodes and anodes can hinder quantitative evaluation of organic substrate-dependent current generation in BESs.

生物电化学系统（BESs）是利用电化学活性细菌（EAB）与电极之间的电化学相互作用的工程系统。BES由于其在生物技术过程中的实用性而备受关注。在BES中，氢通过还原低电位阴极电极上的水而产生。但是，关于氢对EES代谢和生长以及BESs产生的影响的信息很少。在这里，我们研究了EAB模型Shewanella oneidensis对氢气产生电流的影响MR-1。我们发现该菌株利用氢作为电极呼吸的电子供体，从而在有机底物存在下促进电流产生和细胞生长。内膜（IM）醌（即泛醌和甲萘醌），IM醌反应性氢酶Hya和IM结合醌还原酶CymA参与依赖氢的电流产生，这表明Hya和CymA催化IM醌的氧化还原循环。通过F ₀ F ₁有助于质子原动力的产生和ATP的合成-ATP酶。这些发现表明，氢在阴极上的逸出促进了能量代谢以及与阳极相关的利用氢的EAB的生长。结果还表明，阴极和阳极之间的氢循环会阻碍BES中有机底物依赖性电流产生的定量评估。