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Light-Dependent Electrogenic Activity of Cyanobacteria

BACKGROUND: Cyanobacteria account for 20–30% of Earth's primary photosynthetic productivity and convert solar energy into biomass-stored chemical energy at the rate of ∼450 TW [1]. These single-cell microorganisms are resilient predecessors of all higher oxygenic phototrophs and can be found in...

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Autores principales: Pisciotta, John M., Zou, Yongjin, Baskakov, Ilia V.
Formato: Texto
Lenguaje:English
Publicado: Public Library of Science 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2876029/
https://www.ncbi.nlm.nih.gov/pubmed/20520829
http://dx.doi.org/10.1371/journal.pone.0010821
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author Pisciotta, John M.
Zou, Yongjin
Baskakov, Ilia V.
author_facet Pisciotta, John M.
Zou, Yongjin
Baskakov, Ilia V.
author_sort Pisciotta, John M.
collection PubMed
description BACKGROUND: Cyanobacteria account for 20–30% of Earth's primary photosynthetic productivity and convert solar energy into biomass-stored chemical energy at the rate of ∼450 TW [1]. These single-cell microorganisms are resilient predecessors of all higher oxygenic phototrophs and can be found in self-sustaining, nitrogen-fixing communities the world over, from Antarctic glaciers to the Sahara desert [2]. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that diverse genera of cyanobacteria including biofilm-forming and pelagic strains have a conserved light-dependent electrogenic activity, i.e. the ability to transfer electrons to their surroundings in response to illumination. Naturally-growing biofilm-forming photosynthetic consortia also displayed light-dependent electrogenic activity, demonstrating that this phenomenon is not limited to individual cultures. Treatment with site-specific inhibitors revealed the electrons originate at the photosynthetic electron transfer chain (P-ETC). Moreover, electrogenic activity was observed upon illumination only with blue or red but not green light confirming that P-ETC is the source of electrons. The yield of electrons harvested by extracellular electron acceptor to photons available for photosynthesis ranged from 0.05% to 0.3%, although the efficiency of electron harvesting likely varies depending on terminal electron acceptor. CONCLUSIONS/SIGNIFICANCE: The current study illustrates that cyanobacterial electrogenic activity is an important microbiological conduit of solar energy into the biosphere. The mechanism responsible for electrogenic activity in cyanobacteria appears to be fundamentally different from the one exploited in previously discovered electrogenic bacteria, such as Geobacter, where electrons are derived from oxidation of organic compounds and transported via a respiratory electron transfer chain (R-ETC) [3], [4]. The electrogenic pathway of cyanobacteria might be exploited to develop light-sensitive devices or future technologies that convert solar energy into limited amounts of electricity in a self-sustainable, CO(2)-free manner.
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spelling pubmed-28760292010-06-02 Light-Dependent Electrogenic Activity of Cyanobacteria Pisciotta, John M. Zou, Yongjin Baskakov, Ilia V. PLoS One Research Article BACKGROUND: Cyanobacteria account for 20–30% of Earth's primary photosynthetic productivity and convert solar energy into biomass-stored chemical energy at the rate of ∼450 TW [1]. These single-cell microorganisms are resilient predecessors of all higher oxygenic phototrophs and can be found in self-sustaining, nitrogen-fixing communities the world over, from Antarctic glaciers to the Sahara desert [2]. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that diverse genera of cyanobacteria including biofilm-forming and pelagic strains have a conserved light-dependent electrogenic activity, i.e. the ability to transfer electrons to their surroundings in response to illumination. Naturally-growing biofilm-forming photosynthetic consortia also displayed light-dependent electrogenic activity, demonstrating that this phenomenon is not limited to individual cultures. Treatment with site-specific inhibitors revealed the electrons originate at the photosynthetic electron transfer chain (P-ETC). Moreover, electrogenic activity was observed upon illumination only with blue or red but not green light confirming that P-ETC is the source of electrons. The yield of electrons harvested by extracellular electron acceptor to photons available for photosynthesis ranged from 0.05% to 0.3%, although the efficiency of electron harvesting likely varies depending on terminal electron acceptor. CONCLUSIONS/SIGNIFICANCE: The current study illustrates that cyanobacterial electrogenic activity is an important microbiological conduit of solar energy into the biosphere. The mechanism responsible for electrogenic activity in cyanobacteria appears to be fundamentally different from the one exploited in previously discovered electrogenic bacteria, such as Geobacter, where electrons are derived from oxidation of organic compounds and transported via a respiratory electron transfer chain (R-ETC) [3], [4]. The electrogenic pathway of cyanobacteria might be exploited to develop light-sensitive devices or future technologies that convert solar energy into limited amounts of electricity in a self-sustainable, CO(2)-free manner. Public Library of Science 2010-05-25 /pmc/articles/PMC2876029/ /pubmed/20520829 http://dx.doi.org/10.1371/journal.pone.0010821 Text en Pisciotta et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Pisciotta, John M.
Zou, Yongjin
Baskakov, Ilia V.
Light-Dependent Electrogenic Activity of Cyanobacteria
title Light-Dependent Electrogenic Activity of Cyanobacteria
title_full Light-Dependent Electrogenic Activity of Cyanobacteria
title_fullStr Light-Dependent Electrogenic Activity of Cyanobacteria
title_full_unstemmed Light-Dependent Electrogenic Activity of Cyanobacteria
title_short Light-Dependent Electrogenic Activity of Cyanobacteria
title_sort light-dependent electrogenic activity of cyanobacteria
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2876029/
https://www.ncbi.nlm.nih.gov/pubmed/20520829
http://dx.doi.org/10.1371/journal.pone.0010821
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