Metabolism of lactate and sugars by dairy propionibacteria: A review

Abstract

-Dairy propionibacteria are important organisms for the manufacture of Swiss-type cheese, for the biological production of propionate and vitamin 8 12 and have probiotic properties. In ail the se applications, their metabolic activities play a critical role. A complete understanding of propionate fermentation and of the metabolic routes used is therefore necessary. Dairy propionibacteria have a complex metabolism and involves several cycles. Lactate or sugars utilisation yields pyruvate which can be reduced to produce propionate via the transcarboxylase cycles, or oxidised to yield acetate and CO 2 • During the coupled oxidation-reduction, ATP is produced by an electron transport system and fumarate acts as the final acceptor. Although propionibacteria are mainly anaerobes, the electron transport system can be used in the presence of oxygen and they possess the citrate cycle, but can not grow under normal atmospheric oxygen pressure. The proportions of propionate acetate and CO 2 produced vary depending on the strain used and this can be explained, to sorne extent, by their relative ability to utilise pyruvate via reactions of the citrate cycle. The physicochemical environ ment during growth affects propionic acid fermentation; it is impaired by the presence of oxygen and nitrate, but fermentation at acidic pHs enhances propionate production. Fermentation in presence of more than one substrate is complex and still poorly understood. When both L-and D-lactate isomers are available, L-lactate is used preferentially. Although sugar fermentation is more efficient, in the presence of lactate and sugars, there is evidence that lactate is used preferentially. Propionic acid fermentation is affected by the utilisation of amino acids, especially aspartate; co-metabolism of lactate and aspartate results in a lower propionate production and a decrease of the ratio propionate:acetate. There is evidence that the utilisation of the products of proteolysis is an important event in the ripening of Swiss-type chee se and could account for the low propionate:acetate ratios observed in Swiss-type cheese. © Inra/Elsevier, Paris.propionic acid bacteria {lactate { sugar { metabolism Résumé -Métabolisme du lactate et des sucres par les bactéries propioniques laitières: une revue. Les bactéries propioniques laitières sont importantes pour la fabrication de fromages de type emmental, pour la production biologique de propionate et de vitamine 8 12 ainsi que pour leurs propriétés probiotiques. Dans ces domaines, leurs activités métaboliques ont un rôle crucial. Il est donc Oral communication at the 2nd Symposium on Propionibacteria, Cork, Ireland, June 25-27, 1998. * Correspondence and reprints. P.Piveteau@hotmail.com 24 P. Piveteau nécessaire de comprendre de façon approfondie la fermentation propionique et les voies métabo-liques empruntées. Les bactéries propioniques possèdent un métabolisme complexe impliquant plusieurs cycles. Le pyruvate issu de l'utilisation du lactate et des sucres peut être réduit, ce qui conduit à la pr...

Enteric methane emissions in response to ruminal inoculation of Propionibacterium strains in beef cattle fed a mixed diet

“…The lack of survival and persistence of Propionibacterium strains in the rumen observed previously (Vyas et al 2014a) was attributed to absence of ruminal lactate, a preferred substrate for the growth of Propionibacterium spp. Although ruminal lactate was not detectable in the present study, better persistence of Propionibacterium T159 could have been due to utilisation of alternative substrates including glucose as well as amino acids to produce propionate and acetate (Piveteau 1999). The presence of metabolically active Propionibacterium T159 might have accounted for the reduced molar proportion of ruminal acetate; however, lack of significant effect on total CH 4 emissions might be attributed to the inefficacy of Propionibacterium T159 to increase ruminal propionate.…”

Dairy Propionibacteria: Less Conventional Probiotics to Improve the Human and Animal Health

“…Propionibacteria are heterotrophic microorganisms that mean they need an organic carbon source to grow and posses a fermentative metabolism [41][42][43]. They degrade carbohydrates like glucose, galactose, lactose, fructose and other sugars; poliols like glycerol; erythritol and others; and organic acids such as lactic and gluconic acids producing propionic, acetic and CO2 as the main fermentation end-products [1].…”

“…All the reactions of this cycle are reversible. It must be emphasized that the Wood Werkman cycle used by propionibacteria to produce propionate is coupled to oxidative phosphorylation and yields more ATP than in the other bacteria producing propionic acid [42,43].…”

Effects of Propionibacterium strains on ruminal fermentation, nutrient digestibility and methane emissions in beef cattle fed a corn grain finishing diet

“…Propionibacterium strains used in the present study were hypothesized to reduce CH 4 emissions by promoting propionate synthesis in the rumen. Among various substrates, Propionibacterium strains use lactate as the preferred carbon source for propionate synthesis (Piveteau, 1999). Theoretically, two moles of propionate, 1 M of acetate, and 1 M of carbon dioxide can be produced from 3 M of lactate (Piveteau, 1999).…”