Title: Rex in Caldicellulosiruptor bescii : Novel regulon members and its effect on the production of ethanol and overflow metabolites

Abstract

Abstract Rex is a global redox‐sensing transcription factor that senses and responds to the intracellular [ NADH ]/[ NAD ⁺ ] ratio to regulate genes for central metabolism, and a variety of metabolic processes in Gram‐positive bacteria. We decipher and validate four new members of the Rex regulon in Caldicellulosiruptor bescii ; a gene encoding a class V aminotransferase, the HydG FeFe Hydrogenase maturation protein, an oxidoreductase, and a gene encoding a hypothetical protein. Structural genes for the NiFe and FeFe hydrogenases, pyruvate:ferredoxin oxidoreductase, as well as the rex gene itself are also members of this regulon, as has been predicted previously in different organisms. A C. bescii rex deletion strain constructed in an ethanol‐producing strain made 54% more ethanol (0.16 mmol/L) than its genetic parent after 36 hr of fermentation, though only under nitrogen limited conditions. Metabolomic interrogation shows this rex‐ deficient ethanol‐producing strain synthesizes other reduced overflow metabolism products likely in response to more reduced intracellular redox conditions and the accumulation of pyruvate. These results suggest ethanol production is strongly dependent on the native intracellular redox state in C. bescii , and highlight the combined promise of using this gene and manipulation of culture conditions to yield strains capable of producing ethanolmore » at higher yields and final titer.« less

Authors:

Sander, Kyle  ^[1];

• Search DOE PAGES for author "Sander, Kyle"
• Search DOE PAGES for ORCID "0000-0002-5944-7822"

Chung, Daehwan ^[2]; Hyatt, Doug ^[3]; Westpheling, Janet ^[2]; Klingeman, Dawn M. ^[3]; Rodriguez, Jr, Miguel ^[3]; Engle, Nancy L. ^[3]; Tschaplinski, Timothy J. ^[3]; Davison, Brian H. ^[4]; Brown, Steven D.  ^[5]

• Search DOE PAGES for author "Brown, Steven D."
• Search DOE PAGES for ORCID "0000-0002-9281-3898"

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+ Show Author Affiliations

1. Department of Chemical and Biomolecular Engineering University of Tennessee Knoxville Tennessee, Bredesen Center for Interdisciplinary Graduate Research and Education University of Tennessee Knoxville Tennessee, BioEnergy Sciences Center Oak Ridge National Laboratory Oak Ridge Tennessee
2. BioEnergy Sciences Center Oak Ridge National Laboratory Oak Ridge Tennessee, Department of Genetics University of Georgia Athens Georgia
3. BioEnergy Sciences Center Oak Ridge National Laboratory Oak Ridge Tennessee, Biosciences Division Oak Ridge National Laboratory Oak Ridge Tennessee
4. Department of Chemical and Biomolecular Engineering University of Tennessee Knoxville Tennessee, Bredesen Center for Interdisciplinary Graduate Research and Education University of Tennessee Knoxville Tennessee, BioEnergy Sciences Center Oak Ridge National Laboratory Oak Ridge Tennessee, Biosciences Division Oak Ridge National Laboratory Oak Ridge Tennessee
5. Bredesen Center for Interdisciplinary Graduate Research and Education University of Tennessee Knoxville Tennessee, BioEnergy Sciences Center Oak Ridge National Laboratory Oak Ridge Tennessee, Biosciences Division Oak Ridge National Laboratory Oak Ridge Tennessee

Publication Date:

Wed May 23 00:00:00 EDT 2018

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1438932

Alternate Identifier(s):

OSTI ID: 1438933; OSTI ID: 1461944

Grant/Contract Number:  

AC05-00OR22725

Resource Type:

Published Article

Journal Name:

MicrobiologyOpen

Additional Journal Information:

Journal Name: MicrobiologyOpen Journal Volume: 8 Journal Issue: 2; Journal ID: ISSN 2045-8827

Publisher:

Wiley Blackwell (John Wiley & Sons)

Country of Publication:

United Kingdom

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; Caldicellulosiruptor bescii; consolidated bioprocessing; ethanol; Rex