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Appl. Environ. Microbiol., Dec 1996, 4405-4409, Vol 62, No. 12
F Barbirato, P Soucaille and A Bories
When grown in 700 mM glycerol within the pH range 6.0 to 7.5, anaerobic
pH-regulated cultures of Enterobacter agglomerans exhibited an
extracellular accumulation of 3-hydroxypropionaldehyde (3-HPA). This
phenomenon, which causes fermentation cessation, occurred earlier when pH
was low. In contrast, substrate consumption was complete at pH 8. Levels of
glycerol-catabolizing enzymes, i.e., glycerol dehydrogenase and
dihydroxyacetone kinase for the oxidative route and glycerol dehydratase
and 1,3-propanediol dehydrogenase for the reductive route, as well as the
nucleotide pools were determined periodically in the pH 7- and pH
8-regulated cultures. A NAD/NADH ratio of 1.7 was correlated with the
beginning of the production of the inhibitory metabolite. Further
accumulation was dependent on the ratio of glycerol dehydratase activity to
1,3-propanediol dehydrogenase activity. For a ratio higher than 1, 3-HPA
was produced until fermentation ceased, which occurred for the pH
7-regulated culture. At pH 8, a value below 1 was noticed and 3-HPA
accumulation was transient, while the NAD/NADH ratio decreased. The low
rate of glycerol dissimilation following the appearance of 3-HPA in the
culture medium was attributed to the strong inhibitory effect exerted by
3-HPA on glycerol dehydrogenase activity.
Copyright © 1996, American Society for Microbiology
Physiologic Mechanisms Involved in Accumulation of 3-Hydroxypropionaldehyde during Fermentation of Glycerol by Enterobacter agglomerans
Institut National de la Recherche Agronomique, Laboratoire de Biotechnologie de l'Environnement, 11100 Narbonne, and Institut National des Sciences Appliquees, Centre de Bioingenierie Gilbert Durand, Complexe Scientifique de Rangueil, 31077 Toulouse, France
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