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Low oxygen levels contribute to improve photohydrogen production in mixotrophic non-stressed Chlamydomonas cultures

BACKGROUND: Currently, hydrogen fuel is derived mainly from fossil fuels, but there is an increasing interest in clean and sustainable technologies for hydrogen production. In this context, the ability of some photosynthetic microorganisms, particularly cyanobacteria and microalgae, to produce hydro...

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Autores principales: Jurado-Oller, Jose Luis, Dubini, Alexandra, Galván, Aurora, Fernández, Emilio, González-Ballester, David
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4573693/
https://www.ncbi.nlm.nih.gov/pubmed/26388936
http://dx.doi.org/10.1186/s13068-015-0341-9
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author Jurado-Oller, Jose Luis
Dubini, Alexandra
Galván, Aurora
Fernández, Emilio
González-Ballester, David
author_facet Jurado-Oller, Jose Luis
Dubini, Alexandra
Galván, Aurora
Fernández, Emilio
González-Ballester, David
author_sort Jurado-Oller, Jose Luis
collection PubMed
description BACKGROUND: Currently, hydrogen fuel is derived mainly from fossil fuels, but there is an increasing interest in clean and sustainable technologies for hydrogen production. In this context, the ability of some photosynthetic microorganisms, particularly cyanobacteria and microalgae, to produce hydrogen is a promising alternative for renewable, clean-energy production. Among a diverse array of photosynthetic microorganisms able to produce hydrogen, the green algae Chlamydomonas reinhardtii is the model organism widely used to study hydrogen production. Despite the well-known fact that acetate-containing medium enhances hydrogen production in this algae, little is known about the precise role of acetate during this process. RESULTS: We have examined several physiological aspects related to acetate assimilation in the context of hydrogen production metabolism. Measurements of oxygen and CO(2) levels, acetate uptake, and cell growth were performed under different light conditions, and oxygenic regimes. We show that oxygen and light intensity levels control acetate assimilation and modulate hydrogen production. We also demonstrate that the determination of the contribution of the PSII-dependent hydrogen production pathway in mixotrophic cultures, using the photosynthetic inhibitor DCMU, can lead to dissimilar results when used under various oxygenic regimes. The level of inhibition of DCMU in hydrogen production under low light seems to be linked to the acetate uptake rates. Moreover, we highlight the importance of releasing the hydrogen partial pressure to avoid an inherent inhibitory factor on the hydrogen production. CONCLUSION: Low levels of oxygen allow for low acetate uptake rates, and paradoxically, lead to efficient and sustained production of hydrogen. Our data suggest that acetate plays an important role in the hydrogen production process, during non-stressed conditions, other than establishing anaerobiosis, and independent of starch accumulation. Potential metabolic pathways involved in hydrogen production in mixotrophic cultures are discussed. Mixotrophic nutrient-replete cultures under low light are shown to be an alternative for the simultaneous production of hydrogen and biomass. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13068-015-0341-9) contains supplementary material, which is available to authorized users.
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spelling pubmed-45736932015-09-19 Low oxygen levels contribute to improve photohydrogen production in mixotrophic non-stressed Chlamydomonas cultures Jurado-Oller, Jose Luis Dubini, Alexandra Galván, Aurora Fernández, Emilio González-Ballester, David Biotechnol Biofuels Research BACKGROUND: Currently, hydrogen fuel is derived mainly from fossil fuels, but there is an increasing interest in clean and sustainable technologies for hydrogen production. In this context, the ability of some photosynthetic microorganisms, particularly cyanobacteria and microalgae, to produce hydrogen is a promising alternative for renewable, clean-energy production. Among a diverse array of photosynthetic microorganisms able to produce hydrogen, the green algae Chlamydomonas reinhardtii is the model organism widely used to study hydrogen production. Despite the well-known fact that acetate-containing medium enhances hydrogen production in this algae, little is known about the precise role of acetate during this process. RESULTS: We have examined several physiological aspects related to acetate assimilation in the context of hydrogen production metabolism. Measurements of oxygen and CO(2) levels, acetate uptake, and cell growth were performed under different light conditions, and oxygenic regimes. We show that oxygen and light intensity levels control acetate assimilation and modulate hydrogen production. We also demonstrate that the determination of the contribution of the PSII-dependent hydrogen production pathway in mixotrophic cultures, using the photosynthetic inhibitor DCMU, can lead to dissimilar results when used under various oxygenic regimes. The level of inhibition of DCMU in hydrogen production under low light seems to be linked to the acetate uptake rates. Moreover, we highlight the importance of releasing the hydrogen partial pressure to avoid an inherent inhibitory factor on the hydrogen production. CONCLUSION: Low levels of oxygen allow for low acetate uptake rates, and paradoxically, lead to efficient and sustained production of hydrogen. Our data suggest that acetate plays an important role in the hydrogen production process, during non-stressed conditions, other than establishing anaerobiosis, and independent of starch accumulation. Potential metabolic pathways involved in hydrogen production in mixotrophic cultures are discussed. Mixotrophic nutrient-replete cultures under low light are shown to be an alternative for the simultaneous production of hydrogen and biomass. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13068-015-0341-9) contains supplementary material, which is available to authorized users. BioMed Central 2015-09-17 /pmc/articles/PMC4573693/ /pubmed/26388936 http://dx.doi.org/10.1186/s13068-015-0341-9 Text en © Jurado-Oller et al. 2015 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
Jurado-Oller, Jose Luis
Dubini, Alexandra
Galván, Aurora
Fernández, Emilio
González-Ballester, David
Low oxygen levels contribute to improve photohydrogen production in mixotrophic non-stressed Chlamydomonas cultures
title Low oxygen levels contribute to improve photohydrogen production in mixotrophic non-stressed Chlamydomonas cultures
title_full Low oxygen levels contribute to improve photohydrogen production in mixotrophic non-stressed Chlamydomonas cultures
title_fullStr Low oxygen levels contribute to improve photohydrogen production in mixotrophic non-stressed Chlamydomonas cultures
title_full_unstemmed Low oxygen levels contribute to improve photohydrogen production in mixotrophic non-stressed Chlamydomonas cultures
title_short Low oxygen levels contribute to improve photohydrogen production in mixotrophic non-stressed Chlamydomonas cultures
title_sort low oxygen levels contribute to improve photohydrogen production in mixotrophic non-stressed chlamydomonas cultures
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4573693/
https://www.ncbi.nlm.nih.gov/pubmed/26388936
http://dx.doi.org/10.1186/s13068-015-0341-9
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