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The electron‐bifurcating FeFe ‐hydrogenase Hnd is involved in ethanol metabolism in Desulfovibrio fructosovorans grown on pyruvate
Author(s) -
Payne Natalie,
Kpebe Arlette,
Guendon Chloé,
Baffert Carole,
Ros Julien,
Lebrun Régine,
Denis Yann,
Shintu Laetitia,
Brugna Myriam
Publication year - 2022
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.14881
Subject(s) - ferredoxin , hydrogenase , biology , biochemistry , desulfovibrio , nad+ kinase , alcohol dehydrogenase , oxidoreductase , fermentation , bacteria , enzyme , genetics
Abstract Desulfovibrio fructosovorans , a sulfate‐reducing bacterium, possesses six gene clusters encoding six hydrogenases catalyzing the reversible oxidation of H 2 into protons and electrons. Among them, Hnd is an electron‐bifurcating hydrogenase, coupling the exergonic reduction of NAD + to the endergonic reduction of a ferredoxin with electrons derived from H 2 . It was previously hypothesized that its biological function involves the production of NADPH necessary for biosynthetic purposes. However, it was subsequently demonstrated that Hnd is instead a NAD + ‐reducing enzyme, thus its specific function has yet to be established. To understand the physiological role of Hnd in D. fructosovorans , we compared the hnd deletion mutant with the wild‐type strain grown on pyruvate. Growth, metabolite production and consumption, and gene expression were compared under three different growth conditions. Our results indicate that hnd is strongly regulated at the transcriptional level and that its deletion has a drastic effect on the expression of genes for two enzymes, an aldehyde ferredoxin oxidoreductase and an alcohol dehydrogenase. We demonstrated here that Hnd is involved in ethanol metabolism when bacteria grow fermentatively and proposed that Hnd might oxidize part of the H 2 produced during fermentation generating both NADH and reduced ferredoxin for ethanol production via its electron bifurcation mechanism.