Abstract
The ability of a biocatalyst to tolerate furan inhibitors present in hemicellulose hydrolysates is important for the production of renewable chemicals. This study shows EMFR9, a furfural-tolerant mutant of ethanologenic E. coli LY180, has also acquired tolerance to 5-hydroxymethyl furfural (5-HMF). The mechanism of action of 5-HMF and furfural appear similar. Furan tolerance results primarily from lower expression of yqhD and dkgA, two furan reductases with a low K(m) for NADPH. Furan tolerance was also increased by adding plasmids encoding a NADPH/NADH transhydrogenase (pntAB). Together, these results support the hypothesis that the NADPH-dependent reduction of furans by YqhD and DkgA inhibits growth by competing with biosynthesis for this limiting cofactor.
Publication types
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Alcohol Oxidoreductases / biosynthesis
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Alcohol Oxidoreductases / genetics
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Aldehyde Reductase / biosynthesis
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Aldehyde Reductase / genetics
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Anti-Bacterial Agents / pharmacology*
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Biotransformation
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Drug Resistance, Bacterial*
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Escherichia coli / drug effects*
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Escherichia coli / genetics
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Escherichia coli / metabolism*
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Escherichia coli Proteins / biosynthesis
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Escherichia coli Proteins / genetics
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Ethanol / metabolism*
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Furaldehyde / analogs & derivatives*
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Furaldehyde / pharmacology
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Gene Expression
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NADH, NADPH Oxidoreductases / biosynthesis
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NADH, NADPH Oxidoreductases / genetics
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Oxidation-Reduction
Substances
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Anti-Bacterial Agents
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Escherichia coli Proteins
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Ethanol
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5-hydroxymethylfurfural
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Furaldehyde
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Alcohol Oxidoreductases
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DkgA protein, E coli
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Aldehyde Reductase
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YqhD protein, E coli
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NADH, NADPH Oxidoreductases
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NADH-NAD transhydrogenase