The role of AdhE on ethanol tolerance and production in Clostridium thermocellum.

Autor:	Pech-Canul A; Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA., Hammer SK; Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA., Ziegler SJ; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA; Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA., Richardson ID; Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA., Sharma BD; Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA., Maloney MI; Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA., Bomble YJ; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA; Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA., Lynd LR; Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA., Olson DG; Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA. Electronic address: daniel.g.olson@dartmouth.edu.
Jazyk:	angličtina
Zdroj:	The Journal of biological chemistry [J Biol Chem] 2024 Aug; Vol. 300 (8), pp. 107559. Date of Electronic Publication: 2024 Jul 11.
DOI:	10.1016/j.jbc.2024.107559
Abstrakt:	Many anaerobic microorganisms use the bifunctional aldehyde and alcohol dehydrogenase enzyme, AdhE, to produce ethanol. One such organism is Clostridium thermocellum, which is of interest for cellulosic biofuel production. In the course of engineering this organism for improved ethanol tolerance and production, we observed that AdhE was a frequent target of mutations. Here, we characterized those mutations to understand their effects on enzymatic activity, as well ethanol tolerance and product formation in the organism. We found that there is a strong correlation between NADH-linked alcohol dehydrogenase (ADH) activity and ethanol tolerance. Mutations that decrease NADH-linked ADH activity increase ethanol tolerance; correspondingly, mutations that increase NADH-linked ADH activity decrease ethanol tolerance. We also found that the magnitude of ADH activity did not play a significant role in determining ethanol titer. Increasing ADH activity had no effect on ethanol titer. Reducing ADH activity had indeterminate effects on ethanol titer, sometimes increasing and sometimes decreasing it. Finally, this study shows that the cofactor specificity of ADH activity was found to be the primary factor affecting ethanol yield. We expect that these results will inform efforts to use AdhE enzymes in metabolic engineering approaches. Competing Interests: Conflict of interest Lee R. Lynd is the co-founder and CEO of the Terragia corporation (https://terragiabiofuel.com/). Terragia has a financial interest in commercialization of Clostridium thermocellum. The other authors declare that they have no conflicts of interest with the contents of this article. (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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