The Mechanism of Propionic Acid Formation by Veillonella gazogenes

Abstract

This mechanism is according to the scheme: lactate[forward arrow]pyruvate [image]oxaloacetate[forward arrow]wnalate[forward arrow] fumarate-succinate[forward arrow]propionate +CO2. The evidence for this scheme is: (a) Washed suspensions of the organism grown on lactate attack, under anaerobic conditions, pyruvate, oxalacetate, L-malate, fumarate and succinate, but not D-tartrate. (b) Organisms grown on D-tartrate attack it and all the substances listed in (a) except lactate. (c) Succinic acid is quantitatively decarboxylated to propionic acid and CO2. (d) The amt. of propionic acid produced from lactate is influenced by the CO2 concn. in the medium. (e) Fixed CO2 appears as the carboxyl group of propionic acid during fermentation of lactate.