Insights into CO<sub>2</sub> Fixation Pathway of <italic toggle="yes">Clostridium autoethanogenum</italic> by Targeted Mutagenesis

ABSTRACT The future sustainable production of chemicals and fuels from nonpetrochemical resources and reduction of greenhouse gas emissions are two of the greatest societal challenges. Gas fermentation, which utilizes the ability of acetogenic bacteria such as Clostridium autoethanogenum to grow and...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Fungmin Liew, Anne M. Henstra, Klaus Winzer, Michael Köpke, Sean D. Simpson, Nigel P. Minton
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2016
Materias:	Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/4b3a6eb8f956455dbfa08ac2aaec5ac0
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:4b3a6eb8f956455dbfa08ac2aaec5ac0
record_format	dspace
spelling	oai:doaj.org-article:4b3a6eb8f956455dbfa08ac2aaec5ac02021-11-15T15:50:17ZInsights into CO<sub>2</sub> Fixation Pathway of <italic toggle="yes">Clostridium autoethanogenum</italic> by Targeted Mutagenesis10.1128/mBio.00427-162150-7511https://doaj.org/article/4b3a6eb8f956455dbfa08ac2aaec5ac02016-07-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.00427-16https://doaj.org/toc/2150-7511ABSTRACT The future sustainable production of chemicals and fuels from nonpetrochemical resources and reduction of greenhouse gas emissions are two of the greatest societal challenges. Gas fermentation, which utilizes the ability of acetogenic bacteria such as Clostridium autoethanogenum to grow and convert CO2 and CO into low-carbon fuels and chemicals, could potentially provide solutions to both. Acetogens fix these single-carbon gases via the Wood-Ljungdahl pathway. Two enzyme activities are predicted to be essential to the pathway: carbon monoxide dehydrogenase (CODH), which catalyzes the reversible oxidation of CO to CO2, and acetyl coenzyme A (acetyl-CoA) synthase (ACS), which combines with CODH to form a CODH/ACS complex for acetyl-CoA fixation. Despite their pivotal role in carbon fixation, their functions have not been confirmed in vivo. By genetically manipulating all three CODH isogenes (acsA, cooS1, and cooS2) of C. autoethanogenum, we highlighted the functional redundancies of CODH by demonstrating that cooS1 and cooS2 are dispensable for autotrophy. Unexpectedly, the cooS1 inactivation strain showed a significantly reduced lag phase and a higher growth rate than the wild type on H2 and CO2. During heterotrophic growth on fructose, the acsA inactivation strain exhibited 61% reduced biomass and the abolishment of acetate production (a hallmark of acetogens), in favor of ethanol, lactate, and 2,3-butanediol production. A translational readthrough event was discovered in the uniquely truncated (compared to those of other acetogens) C. autoethanogenum acsA gene. Insights gained from studying the function of CODH enhance the overall understanding of autotrophy and can be used for optimization of biotechnological production of ethanol and other commodities via gas fermentation. IMPORTANCE Gas fermentation is an emerging technology that converts the greenhouse gases CO2 and CO in industrial waste gases and gasified biomass into fuels and chemical commodities. Acetogenic bacteria such as Clostridium autoethanogenum are central to this bioprocess, but the molecular and genetic characterization of this microorganism is currently lacking. By targeting all three of the isogenes encoding carbon monoxide dehydrogenase (CODH) in C. autoethanogenum, we identified the most important CODH isogene for carbon fixation and demonstrated that genetic inactivation of CODH could improve autotrophic growth. This study shows that disabling of the Wood-Ljungdahl pathway via the inactivation of acsA (encodes CODH) significantly impairs heterotrophic growth and alters the product profile by abolishing acetate production. Moreover, we discovered a previously undescribed mechanism for controlling the production of this enzyme. This study provides valuable insights into the acetogenic pathway and can be used for the development of more efficient and productive strains for gas fermentation.Fungmin LiewAnne M. HenstraKlaus WinzerMichael KöpkeSean D. SimpsonNigel P. MintonAmerican Society for MicrobiologyarticleMicrobiologyQR1-502ENmBio, Vol 7, Iss 3 (2016)
institution	DOAJ
collection	DOAJ
language	EN
topic	Microbiology QR1-502
spellingShingle	Microbiology QR1-502 Fungmin Liew Anne M. Henstra Klaus Winzer Michael Köpke Sean D. Simpson Nigel P. Minton Insights into CO<sub>2</sub> Fixation Pathway of <italic toggle="yes">Clostridium autoethanogenum</italic> by Targeted Mutagenesis
description	ABSTRACT The future sustainable production of chemicals and fuels from nonpetrochemical resources and reduction of greenhouse gas emissions are two of the greatest societal challenges. Gas fermentation, which utilizes the ability of acetogenic bacteria such as Clostridium autoethanogenum to grow and convert CO2 and CO into low-carbon fuels and chemicals, could potentially provide solutions to both. Acetogens fix these single-carbon gases via the Wood-Ljungdahl pathway. Two enzyme activities are predicted to be essential to the pathway: carbon monoxide dehydrogenase (CODH), which catalyzes the reversible oxidation of CO to CO2, and acetyl coenzyme A (acetyl-CoA) synthase (ACS), which combines with CODH to form a CODH/ACS complex for acetyl-CoA fixation. Despite their pivotal role in carbon fixation, their functions have not been confirmed in vivo. By genetically manipulating all three CODH isogenes (acsA, cooS1, and cooS2) of C. autoethanogenum, we highlighted the functional redundancies of CODH by demonstrating that cooS1 and cooS2 are dispensable for autotrophy. Unexpectedly, the cooS1 inactivation strain showed a significantly reduced lag phase and a higher growth rate than the wild type on H2 and CO2. During heterotrophic growth on fructose, the acsA inactivation strain exhibited 61% reduced biomass and the abolishment of acetate production (a hallmark of acetogens), in favor of ethanol, lactate, and 2,3-butanediol production. A translational readthrough event was discovered in the uniquely truncated (compared to those of other acetogens) C. autoethanogenum acsA gene. Insights gained from studying the function of CODH enhance the overall understanding of autotrophy and can be used for optimization of biotechnological production of ethanol and other commodities via gas fermentation. IMPORTANCE Gas fermentation is an emerging technology that converts the greenhouse gases CO2 and CO in industrial waste gases and gasified biomass into fuels and chemical commodities. Acetogenic bacteria such as Clostridium autoethanogenum are central to this bioprocess, but the molecular and genetic characterization of this microorganism is currently lacking. By targeting all three of the isogenes encoding carbon monoxide dehydrogenase (CODH) in C. autoethanogenum, we identified the most important CODH isogene for carbon fixation and demonstrated that genetic inactivation of CODH could improve autotrophic growth. This study shows that disabling of the Wood-Ljungdahl pathway via the inactivation of acsA (encodes CODH) significantly impairs heterotrophic growth and alters the product profile by abolishing acetate production. Moreover, we discovered a previously undescribed mechanism for controlling the production of this enzyme. This study provides valuable insights into the acetogenic pathway and can be used for the development of more efficient and productive strains for gas fermentation.
format	article
author	Fungmin Liew Anne M. Henstra Klaus Winzer Michael Köpke Sean D. Simpson Nigel P. Minton
author_facet	Fungmin Liew Anne M. Henstra Klaus Winzer Michael Köpke Sean D. Simpson Nigel P. Minton
author_sort	Fungmin Liew
title	Insights into CO<sub>2</sub> Fixation Pathway of <italic toggle="yes">Clostridium autoethanogenum</italic> by Targeted Mutagenesis
title_short	Insights into CO<sub>2</sub> Fixation Pathway of <italic toggle="yes">Clostridium autoethanogenum</italic> by Targeted Mutagenesis
title_full	Insights into CO<sub>2</sub> Fixation Pathway of <italic toggle="yes">Clostridium autoethanogenum</italic> by Targeted Mutagenesis
title_fullStr	Insights into CO<sub>2</sub> Fixation Pathway of <italic toggle="yes">Clostridium autoethanogenum</italic> by Targeted Mutagenesis
title_full_unstemmed	Insights into CO<sub>2</sub> Fixation Pathway of <italic toggle="yes">Clostridium autoethanogenum</italic> by Targeted Mutagenesis
title_sort	insights into co<sub>2</sub> fixation pathway of <italic toggle="yes">clostridium autoethanogenum</italic> by targeted mutagenesis
publisher	American Society for Microbiology
publishDate	2016
url	https://doaj.org/article/4b3a6eb8f956455dbfa08ac2aaec5ac0
work_keys_str_mv	AT fungminliew insightsintocosub2subfixationpathwayofitalictoggleyesclostridiumautoethanogenumitalicbytargetedmutagenesis AT annemhenstra insightsintocosub2subfixationpathwayofitalictoggleyesclostridiumautoethanogenumitalicbytargetedmutagenesis AT klauswinzer insightsintocosub2subfixationpathwayofitalictoggleyesclostridiumautoethanogenumitalicbytargetedmutagenesis AT michaelkopke insightsintocosub2subfixationpathwayofitalictoggleyesclostridiumautoethanogenumitalicbytargetedmutagenesis AT seandsimpson insightsintocosub2subfixationpathwayofitalictoggleyesclostridiumautoethanogenumitalicbytargetedmutagenesis AT nigelpminton insightsintocosub2subfixationpathwayofitalictoggleyesclostridiumautoethanogenumitalicbytargetedmutagenesis
_version_	1718427396558815232

Insights into CO<sub>2</sub> Fixation Pathway of <italic toggle="yes">Clostridium autoethanogenum</italic> by Targeted Mutagenesis

Ejemplares similares