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Kinetic and thermodynamic control of butyrate conversion in non-defined methanogenic communities

Many anaerobic conversions proceed close to thermodynamic equilibrium and the microbial groups involved need to share their low energy budget to survive at the thermodynamic boundary of life. This study aimed to investigate the kinetic and thermodynamic control mechanisms of the electron transfer du...

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Autores principales: Junicke, H., van Loosdrecht, M. C. M., Kleerebezem, R.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Berlin Heidelberg 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4703631/
https://www.ncbi.nlm.nih.gov/pubmed/26403924
http://dx.doi.org/10.1007/s00253-015-6971-9
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author Junicke, H.
van Loosdrecht, M. C. M.
Kleerebezem, R.
author_facet Junicke, H.
van Loosdrecht, M. C. M.
Kleerebezem, R.
author_sort Junicke, H.
collection PubMed
description Many anaerobic conversions proceed close to thermodynamic equilibrium and the microbial groups involved need to share their low energy budget to survive at the thermodynamic boundary of life. This study aimed to investigate the kinetic and thermodynamic control mechanisms of the electron transfer during syntrophic butyrate conversion in non-defined methanogenic communities. Despite the rather low energy content of butyrate, results demonstrate unequal energy sharing between the butyrate-utilizing species (17 %), the hydrogenotrophic methanogens (9–10 %), and the acetoclastic methanogens (73–74 %). As a key finding, the energy disproportion resulted in different growth strategies of the syntrophic partners. Compared to the butyrate-utilizing partner, the hydrogenotrophic methanogens compensated their lower biomass yield per mole of electrons transferred with a 2-fold higher biomass-specific electron transfer rate. Apart from these thermodynamic control mechanisms, experiments revealed a ten times lower hydrogen inhibition constant on butyrate conversion than proposed by the Anaerobic Digestion Model No. 1, suggesting a much stronger inhibitory effect of hydrogen on anaerobic butyrate conversion. At hydrogen partial pressures exceeding 40 Pa and at bicarbonate limited conditions, a shift from methanogenesis to reduced product formation was observed which indicates an important role of the hydrogen partial pressure in redirecting electron fluxes towards reduced products such as butanol. The findings of this study demonstrate that a careful consideration of thermodynamics and kinetics is required to advance our current understanding of flux regulation in energy-limited syntrophic ecosystems. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00253-015-6971-9) contains supplementary material, which is available to authorized users.
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spelling pubmed-47036312016-01-12 Kinetic and thermodynamic control of butyrate conversion in non-defined methanogenic communities Junicke, H. van Loosdrecht, M. C. M. Kleerebezem, R. Appl Microbiol Biotechnol Environmental Biotechnology Many anaerobic conversions proceed close to thermodynamic equilibrium and the microbial groups involved need to share their low energy budget to survive at the thermodynamic boundary of life. This study aimed to investigate the kinetic and thermodynamic control mechanisms of the electron transfer during syntrophic butyrate conversion in non-defined methanogenic communities. Despite the rather low energy content of butyrate, results demonstrate unequal energy sharing between the butyrate-utilizing species (17 %), the hydrogenotrophic methanogens (9–10 %), and the acetoclastic methanogens (73–74 %). As a key finding, the energy disproportion resulted in different growth strategies of the syntrophic partners. Compared to the butyrate-utilizing partner, the hydrogenotrophic methanogens compensated their lower biomass yield per mole of electrons transferred with a 2-fold higher biomass-specific electron transfer rate. Apart from these thermodynamic control mechanisms, experiments revealed a ten times lower hydrogen inhibition constant on butyrate conversion than proposed by the Anaerobic Digestion Model No. 1, suggesting a much stronger inhibitory effect of hydrogen on anaerobic butyrate conversion. At hydrogen partial pressures exceeding 40 Pa and at bicarbonate limited conditions, a shift from methanogenesis to reduced product formation was observed which indicates an important role of the hydrogen partial pressure in redirecting electron fluxes towards reduced products such as butanol. The findings of this study demonstrate that a careful consideration of thermodynamics and kinetics is required to advance our current understanding of flux regulation in energy-limited syntrophic ecosystems. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00253-015-6971-9) contains supplementary material, which is available to authorized users. Springer Berlin Heidelberg 2015-09-25 2016 /pmc/articles/PMC4703631/ /pubmed/26403924 http://dx.doi.org/10.1007/s00253-015-6971-9 Text en © The Author(s) 2015 Open Access This 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.
spellingShingle Environmental Biotechnology
Junicke, H.
van Loosdrecht, M. C. M.
Kleerebezem, R.
Kinetic and thermodynamic control of butyrate conversion in non-defined methanogenic communities
title Kinetic and thermodynamic control of butyrate conversion in non-defined methanogenic communities
title_full Kinetic and thermodynamic control of butyrate conversion in non-defined methanogenic communities
title_fullStr Kinetic and thermodynamic control of butyrate conversion in non-defined methanogenic communities
title_full_unstemmed Kinetic and thermodynamic control of butyrate conversion in non-defined methanogenic communities
title_short Kinetic and thermodynamic control of butyrate conversion in non-defined methanogenic communities
title_sort kinetic and thermodynamic control of butyrate conversion in non-defined methanogenic communities
topic Environmental Biotechnology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4703631/
https://www.ncbi.nlm.nih.gov/pubmed/26403924
http://dx.doi.org/10.1007/s00253-015-6971-9
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