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Accelerated Electro-Fermentation of Acetoin in Escherichia coli by Identifying Physiological Limitations of the Electron Transfer Kinetics and the Central Metabolism

Anode-assisted fermentations offer the benefit of an anoxic fermentation routine that can be applied to produce end-products with an oxidation state independent from the substrate. The whole cell biocatalyst transfers the surplus of electrons to an electrode that can be used as a non-depletable elec...

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Autores principales: Beblawy, Sebastian, Philipp, Laura-Alina, Gescher, Johannes
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7700339/
https://www.ncbi.nlm.nih.gov/pubmed/33238546
http://dx.doi.org/10.3390/microorganisms8111843
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author Beblawy, Sebastian
Philipp, Laura-Alina
Gescher, Johannes
author_facet Beblawy, Sebastian
Philipp, Laura-Alina
Gescher, Johannes
author_sort Beblawy, Sebastian
collection PubMed
description Anode-assisted fermentations offer the benefit of an anoxic fermentation routine that can be applied to produce end-products with an oxidation state independent from the substrate. The whole cell biocatalyst transfers the surplus of electrons to an electrode that can be used as a non-depletable electron acceptor. So far, anode-assisted fermentations were shown to provide high carbon efficiencies but low space-time yields. This study aimed at increasing space-time yields of an Escherichia coli-based anode-assisted fermentation of glucose to acetoin. The experiments build on an obligate respiratory strain, that was advanced using selective adaptation and targeted strain development. Several transfers under respiratory conditions led to point mutations in the pfl, aceF and rpoC gene. These mutations increased anoxic growth by three-fold. Furthermore, overexpression of genes encoding a synthetic electron transport chain to methylene blue increased the electron transfer rate by 2.45-fold. Overall, these measures and a medium optimization increased the space-time yield in an electrode-assisted fermentation by 3.6-fold.
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spelling pubmed-77003392020-11-30 Accelerated Electro-Fermentation of Acetoin in Escherichia coli by Identifying Physiological Limitations of the Electron Transfer Kinetics and the Central Metabolism Beblawy, Sebastian Philipp, Laura-Alina Gescher, Johannes Microorganisms Article Anode-assisted fermentations offer the benefit of an anoxic fermentation routine that can be applied to produce end-products with an oxidation state independent from the substrate. The whole cell biocatalyst transfers the surplus of electrons to an electrode that can be used as a non-depletable electron acceptor. So far, anode-assisted fermentations were shown to provide high carbon efficiencies but low space-time yields. This study aimed at increasing space-time yields of an Escherichia coli-based anode-assisted fermentation of glucose to acetoin. The experiments build on an obligate respiratory strain, that was advanced using selective adaptation and targeted strain development. Several transfers under respiratory conditions led to point mutations in the pfl, aceF and rpoC gene. These mutations increased anoxic growth by three-fold. Furthermore, overexpression of genes encoding a synthetic electron transport chain to methylene blue increased the electron transfer rate by 2.45-fold. Overall, these measures and a medium optimization increased the space-time yield in an electrode-assisted fermentation by 3.6-fold. MDPI 2020-11-23 /pmc/articles/PMC7700339/ /pubmed/33238546 http://dx.doi.org/10.3390/microorganisms8111843 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Beblawy, Sebastian
Philipp, Laura-Alina
Gescher, Johannes
Accelerated Electro-Fermentation of Acetoin in Escherichia coli by Identifying Physiological Limitations of the Electron Transfer Kinetics and the Central Metabolism
title Accelerated Electro-Fermentation of Acetoin in Escherichia coli by Identifying Physiological Limitations of the Electron Transfer Kinetics and the Central Metabolism
title_full Accelerated Electro-Fermentation of Acetoin in Escherichia coli by Identifying Physiological Limitations of the Electron Transfer Kinetics and the Central Metabolism
title_fullStr Accelerated Electro-Fermentation of Acetoin in Escherichia coli by Identifying Physiological Limitations of the Electron Transfer Kinetics and the Central Metabolism
title_full_unstemmed Accelerated Electro-Fermentation of Acetoin in Escherichia coli by Identifying Physiological Limitations of the Electron Transfer Kinetics and the Central Metabolism
title_short Accelerated Electro-Fermentation of Acetoin in Escherichia coli by Identifying Physiological Limitations of the Electron Transfer Kinetics and the Central Metabolism
title_sort accelerated electro-fermentation of acetoin in escherichia coli by identifying physiological limitations of the electron transfer kinetics and the central metabolism
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7700339/
https://www.ncbi.nlm.nih.gov/pubmed/33238546
http://dx.doi.org/10.3390/microorganisms8111843
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