Modulating membrane composition alters free fatty acid tolerance in Escherichia coli.

Microbial synthesis of free fatty acids (FFA) is a promising strategy for converting renewable sugars to advanced biofuels and oleochemicals. Unfortunately, FFA production negatively impacts membrane integrity and cell viability in Escherichia coli, the dominant host in which FFA production has been...

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Autores principales:	Rebecca M Lennen, Brian F Pfleger
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2013
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/65bbd79267f2431fb6c5b6e0ed2334e2
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spelling	oai:doaj.org-article:65bbd79267f2431fb6c5b6e0ed2334e22021-11-18T08:00:46ZModulating membrane composition alters free fatty acid tolerance in Escherichia coli.1932-620310.1371/journal.pone.0054031https://doaj.org/article/65bbd79267f2431fb6c5b6e0ed2334e22013-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/23349781/pdf/?tool=EBIhttps://doaj.org/toc/1932-6203Microbial synthesis of free fatty acids (FFA) is a promising strategy for converting renewable sugars to advanced biofuels and oleochemicals. Unfortunately, FFA production negatively impacts membrane integrity and cell viability in Escherichia coli, the dominant host in which FFA production has been studied. These negative effects provide a selective pressure against FFA production that could lead to genetic instability at industrial scale. In prior work, an engineered E. coli strain harboring an expression plasmid for the Umbellularia californica acyl-acyl carrier protein (ACP) thioesterase was shown to have highly elevated levels of unsaturated fatty acids in the cell membrane. The change in membrane content was hypothesized to be one underlying cause of the negative physiological effects associated with FFA production. In this work, a connection between the regulator of unsaturated fatty acid biosynthesis in E. coli, FabR, thioesterase expression, and unsaturated membrane content was established. A strategy for restoring normal membrane saturation levels and increasing tolerance towards endogenous production of FFAs was implemented by modulating acyl-ACP pools with a second thioesterase (from Geobacillus sp. Y412MC10) that primarily targets medium chain length, unsaturated acyl-ACPs. The strategy succeeded in restoring membrane content and improving viability in FFA producing E. coli while maintaining FFA titers. However, the restored fitness did not increase FFA productivity, indicating the existence of additional metabolic or regulatory barriers.Rebecca M LennenBrian F PflegerPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 8, Iss 1, p e54031 (2013)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Rebecca M Lennen Brian F Pfleger Modulating membrane composition alters free fatty acid tolerance in Escherichia coli.
description	Microbial synthesis of free fatty acids (FFA) is a promising strategy for converting renewable sugars to advanced biofuels and oleochemicals. Unfortunately, FFA production negatively impacts membrane integrity and cell viability in Escherichia coli, the dominant host in which FFA production has been studied. These negative effects provide a selective pressure against FFA production that could lead to genetic instability at industrial scale. In prior work, an engineered E. coli strain harboring an expression plasmid for the Umbellularia californica acyl-acyl carrier protein (ACP) thioesterase was shown to have highly elevated levels of unsaturated fatty acids in the cell membrane. The change in membrane content was hypothesized to be one underlying cause of the negative physiological effects associated with FFA production. In this work, a connection between the regulator of unsaturated fatty acid biosynthesis in E. coli, FabR, thioesterase expression, and unsaturated membrane content was established. A strategy for restoring normal membrane saturation levels and increasing tolerance towards endogenous production of FFAs was implemented by modulating acyl-ACP pools with a second thioesterase (from Geobacillus sp. Y412MC10) that primarily targets medium chain length, unsaturated acyl-ACPs. The strategy succeeded in restoring membrane content and improving viability in FFA producing E. coli while maintaining FFA titers. However, the restored fitness did not increase FFA productivity, indicating the existence of additional metabolic or regulatory barriers.
format	article
author	Rebecca M Lennen Brian F Pfleger
author_facet	Rebecca M Lennen Brian F Pfleger
author_sort	Rebecca M Lennen
title	Modulating membrane composition alters free fatty acid tolerance in Escherichia coli.
title_short	Modulating membrane composition alters free fatty acid tolerance in Escherichia coli.
title_full	Modulating membrane composition alters free fatty acid tolerance in Escherichia coli.
title_fullStr	Modulating membrane composition alters free fatty acid tolerance in Escherichia coli.
title_full_unstemmed	Modulating membrane composition alters free fatty acid tolerance in Escherichia coli.
title_sort	modulating membrane composition alters free fatty acid tolerance in escherichia coli.
publisher	Public Library of Science (PLoS)
publishDate	2013
url	https://doaj.org/article/65bbd79267f2431fb6c5b6e0ed2334e2
work_keys_str_mv	AT rebeccamlennen modulatingmembranecompositionaltersfreefattyacidtoleranceinescherichiacoli AT brianfpfleger modulatingmembranecompositionaltersfreefattyacidtoleranceinescherichiacoli
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Modulating membrane composition alters free fatty acid tolerance in Escherichia coli.

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