Cell and ATP Yields of Citrobacter freundii Growing with Fumarate and H2 or Formate in Continuous Culture (original) (raw)

Out of 19 strains belonging to the family Enterobacteriaceae only Escherichia coli and Citrobacter strains fermented fumarate exclusively to succinate. This fermentation was dependent on the presence of molecular hydrogen or formate. The inability of these microorganisms to convert fumarate to succinate, acetate and C02 correlated with their lack, or low activity, of oxaloacetate decarboxylase. Continuous culture experiments were performed with Citrobacter freundii in minimal or complex medium with fumarate + H2 or formate, and the growth parameters were determined. From the data obtained, a Ymf UBmXarat arat e di&,,ilat& value of 10.5 & 0.8 g dry wt per mol fumarate dissimilated was calculated. This value demonstrates that, per mol fumarate reduced, at least 0-6 f 0.05 mol ATP is produced and subsequently used for biosynthetic purposes.