Conversion of lactate-C14 to propionate by the rumen microflora.

Baldwin, R. L. (Michigan State University, East Lansing), W. A. Wood, and R. S. Emery. Conversion of lactate-C(14) to propionate by the rumen microflora. J. Bacteriol. 83:907-913. 1962.-Rumen microflora enriched on five different diets calculated to present increasing carbohydrate or lactate availability were used to determine the contribution of the randomizing (succinate) and nonrandomizing (acrylate) routes to propionate with lactate-2-C(14) and -3-C(14) as substrates. Propionate was labeled as though 70 to 90% was formed via the nonrandomizing route. This percentage was highest on diets containing high levels of carbohydrate or lactate or both. Evidence for the presence of succinic dehydrogenase, acetokinase, phosphotransacetylase, and coenzyme A transphorase was obtained with cell-free extracts. Propionate-2-C(14) and lactate-2-C(14) were converted by extracts to the activated derivatives of acrylate, lactate, propionate, and acetate.