Metabolism of Propane, n -Propylamine, and Propionate by Hydrocarbon-Utilizing Bacteria

Abstract

Studies were conducted on the oxidation and assimilation of various three-carbon compounds by a gram-positive rod isolated from soil and designated strain R-22. This organism can utilize propane, propionate, or n -propylamine as sole source of carbon and energy. Respiration rates, enzyme assays, and 14 CO 2 incorporation experiments suggest that propane is metabolized via methyl ketone formation; propionate and n -propylamine are metabolized via the methylmalonyl-succinate pathway. Isocitrate lyase activity was found in cells grown on acetate and was not present in cells grown on propionate or n -propylamine. 14 CO 2 was incorporated into pyruvate when propionate and n -propylamine were oxidized in the presence of NaAsO 2 , but insignificant radioactivity was found in pyruvate produced during the oxidation of propane and acetone. The n -propylamine dissimilatory mechanism was inducible in strain R-22, and amine dehydrogenase activity was detected in cells grown on n -propylamine. Radiorespirometer and 14 CO 2 incorporation studies with several propane-utilizing organisms indicate that the methylmalonyl-succinate pathway is the predominant one for the metabolism of propionate.