Lactococcus lactis catalyses electricity generation at microbial fuel cell anodes via excretion of a soluble quinone
Lactococcus lactis catalyses electricity generation at microbial fuel cell anodes via excretion of a soluble quinone
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DOI：
10.1016/j.bioelechem.2009.04.001
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发表时间：
2009-09-01
影响因子：
5
通讯作者：
Kano, Kenji
中科院分区：
文献类型：
--
作者：
Freguia, Stefano;Masuda, Masaki;Kano, Kenji
乳酸乳球菌（Lactococcus lactis）是一种革兰氏阳性的纯乳酸发酵菌，已知其产生几种膜结合醌，其能够介导电子转移到细胞外电子受体，如Fe 3+、Cu 2+和六氰基铁酸盐。在这里，我们表明这种细菌还能够通过利用至少两种可溶性氧化还原介体来进行细胞外电子转移到阳极，正如开发的两步催化电流所表明的那样。本文通过标准氧化还原电位、细菌利用外源提供的醌的能力以及高效液相色谱结合紫外光谱分析，提出这两种介质之一是2-氨基-3-二羧基-1，4-萘醌（ACNQ）。在发电过程中，乳酸乳杆菌稍微偏离其正常的同型乳酸代谢排泄乙酸和丙酮酸的化学计量的量相对于电流。在这一代谢过程中，阳极起到了产乙酸发酵的电子汇的作用。乳酸乳球菌通过分泌氧化还原介质自催化阳极电子转移的发现是显著的，因为革兰氏阳性菌纯培养物的细胞外电子转移机制以前从未被阐明。(C)2009爱思唯尔有限公司版权所有。
Lactococcus lactis is a gram-positive, normally homolactic fermenter that is known to produce several kinds of membrane associated quinones, which are able to mediate electron transfer to extracellular electron acceptors such as Fe3+, Cu2+ and hexacyanoferrate. Here we show that this bacterium is also capable of performing extracellular electron transfer to anodes by utilizing at least two soluble redox mediators, as suggested by the two-step catalytic current developed. One of these two mediators was herein suggested to be 2-amino-3-dicarboxy-1,4-naphthoquinone (ACNQ), via evaluation of standard redox potential, ability of the bacterium to exploit the quinone when exogenously provided, as well as by high performance liquid chromatography coupled with UV spectrum analysis. During electricity generation, L lactis slightly deviated from its normal homolactic metabolism by excreting acetate and pyruvate in stoichiometric amounts with respect to the electrical current. In this metabolism, the anode takes on the role of electron sink for acetogenic fermentation. The finding that L lactis self-catalyses anodic electron transfer by excretion of redox mediators is remarkable as the mechanisms of extracellular electron transfer by pure cultures of gram-positive bacteria had previously never been elucidated. (C) 2009 Elsevier B.V. All rights reserved.