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Less biomass and intracellular glutamate in anodic biofilms lead to efficient electricity generation by microbial fuel cells
BACKGROUND: Using a microbial fuel cell (MFC), we observed that a complex microbial community decomposed starch and transferred electrons to a graphite felt anode to generate current. In spite of the same reactor configuration, inoculum, substrate, temperature, and pH, MFCs produced different curren...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6442422/ https://www.ncbi.nlm.nih.gov/pubmed/30976322 http://dx.doi.org/10.1186/s13068-019-1414-y |
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author | Sasaki, Daisuke Sasaki, Kengo Tsuge, Yota Kondo, Akihiko |
author_facet | Sasaki, Daisuke Sasaki, Kengo Tsuge, Yota Kondo, Akihiko |
author_sort | Sasaki, Daisuke |
collection | PubMed |
description | BACKGROUND: Using a microbial fuel cell (MFC), we observed that a complex microbial community decomposed starch and transferred electrons to a graphite felt anode to generate current. In spite of the same reactor configuration, inoculum, substrate, temperature, and pH, MFCs produced different current and power density. To understand which factor(s) affected electricity generation, here, we analyzed a complex microbial community in an anodic biofilm and fermentation broth using Illumina MiSeq sequencing and metabolomics. RESULTS: Microbial biomass on the anode was lower in MFCs generating more electricity (0.09–0.16 mg cm(−2)-anode) than in those generating less electricity (0.60–2.80 mg cm(−2)-anode), while being equal (3890–4196 mg L(−1)-broth) in the fermentation broth over the same operational period. Chemical oxygen demand removal and acetate concentration were also similar in fermentation broths. MFCs generating more electricity had relatively more exoelectrogenic bacteria, such as Geobacter sp., but fewer acetate-utilizing Methanosarcina sp. and/or Lactococcus sp. in anodic biofilms. Accordingly, anodic biofilms generating more electricity presented higher levels of most intracellular metabolites related to the tricarboxylic acid cycle and a higher intracellular ATP/ADP ratio, but a lower intracellular NADH/NAD(+) ratio. Moreover, the level of intracellular glutamate, an essential metabolite for microbial anabolic reactions, correlated negatively with current density. CONCLUSION: Microbial growth on the anode and intracellular glutamate levels negatively affect electricity generation by MFCs. Reduced formation of anodic biofilm, in which intracellular glutamate concentration is 33.9 μmol g-cell(−1) or less, favors the growth of acetate-utilizing Geobacter sp. on the anode and improves current generation. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13068-019-1414-y) contains supplementary material, which is available to authorized users. |
format | Online Article Text |
id | pubmed-6442422 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-64424222019-04-11 Less biomass and intracellular glutamate in anodic biofilms lead to efficient electricity generation by microbial fuel cells Sasaki, Daisuke Sasaki, Kengo Tsuge, Yota Kondo, Akihiko Biotechnol Biofuels Research BACKGROUND: Using a microbial fuel cell (MFC), we observed that a complex microbial community decomposed starch and transferred electrons to a graphite felt anode to generate current. In spite of the same reactor configuration, inoculum, substrate, temperature, and pH, MFCs produced different current and power density. To understand which factor(s) affected electricity generation, here, we analyzed a complex microbial community in an anodic biofilm and fermentation broth using Illumina MiSeq sequencing and metabolomics. RESULTS: Microbial biomass on the anode was lower in MFCs generating more electricity (0.09–0.16 mg cm(−2)-anode) than in those generating less electricity (0.60–2.80 mg cm(−2)-anode), while being equal (3890–4196 mg L(−1)-broth) in the fermentation broth over the same operational period. Chemical oxygen demand removal and acetate concentration were also similar in fermentation broths. MFCs generating more electricity had relatively more exoelectrogenic bacteria, such as Geobacter sp., but fewer acetate-utilizing Methanosarcina sp. and/or Lactococcus sp. in anodic biofilms. Accordingly, anodic biofilms generating more electricity presented higher levels of most intracellular metabolites related to the tricarboxylic acid cycle and a higher intracellular ATP/ADP ratio, but a lower intracellular NADH/NAD(+) ratio. Moreover, the level of intracellular glutamate, an essential metabolite for microbial anabolic reactions, correlated negatively with current density. CONCLUSION: Microbial growth on the anode and intracellular glutamate levels negatively affect electricity generation by MFCs. Reduced formation of anodic biofilm, in which intracellular glutamate concentration is 33.9 μmol g-cell(−1) or less, favors the growth of acetate-utilizing Geobacter sp. on the anode and improves current generation. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13068-019-1414-y) contains supplementary material, which is available to authorized users. BioMed Central 2019-04-01 /pmc/articles/PMC6442422/ /pubmed/30976322 http://dx.doi.org/10.1186/s13068-019-1414-y Text en © The Author(s) 2019 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
spellingShingle | Research Sasaki, Daisuke Sasaki, Kengo Tsuge, Yota Kondo, Akihiko Less biomass and intracellular glutamate in anodic biofilms lead to efficient electricity generation by microbial fuel cells |
title | Less biomass and intracellular glutamate in anodic biofilms lead to efficient electricity generation by microbial fuel cells |
title_full | Less biomass and intracellular glutamate in anodic biofilms lead to efficient electricity generation by microbial fuel cells |
title_fullStr | Less biomass and intracellular glutamate in anodic biofilms lead to efficient electricity generation by microbial fuel cells |
title_full_unstemmed | Less biomass and intracellular glutamate in anodic biofilms lead to efficient electricity generation by microbial fuel cells |
title_short | Less biomass and intracellular glutamate in anodic biofilms lead to efficient electricity generation by microbial fuel cells |
title_sort | less biomass and intracellular glutamate in anodic biofilms lead to efficient electricity generation by microbial fuel cells |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6442422/ https://www.ncbi.nlm.nih.gov/pubmed/30976322 http://dx.doi.org/10.1186/s13068-019-1414-y |
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