Oxidation of pyruvic acid oxime by soil organisms

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Abstract
Oximes of the alpha-ketoacids (pyruvic, phenylpyruvic, oxalacetic and alpha-ketoglutaric) are readily nitrified in soil. The oximes of salicyl-aldehyde, furil, arabinose, acetone, formaldehyde, acetoacetate ester, and benzoin are inert in soil as nitrite-formers and do not inhibit nitrification of pyruvic-oxime in soil. Among 6 sulfanilamide derivatives tested, sulfadiazine (0.005%) has the most marked inhibitory action on nitrite formation from pyruvic-oxime in soil. Chloramphenicol (1 in 40000) is highly inhibitory, but penicillin and streptomycin are relatively inert under soil conditions. p-Aminosalicylic acid has a small inhibitory action, but nitrourea (0.0033 [image]), which completely inhibits nitrite oxidation in soil, has no inhibitory effect on nitrite formation from pyruvic oxime. Details are given of the isolation and characterization of organisms in soil and in feces capable of oxidizing pyruvic oxime. Three species of organisms, attacking pyruvic oxime were isolated from soil. Two of the species fall into the genus Achromobacter; the 3d is identified as a Corynebacterium. Among 22 stock cultures of bacteria tested for their abilities to proliferate on a pyruvic oxime medium, a few gave sparse growth and none formed nitrite. Using washed suspensions of Achromobacter sp. it was found that during the oxidation of pyruvic oxime, the ratio of nitrite production to O2 uptake remains constant. The results of perfusion and manometric expts. indicate that alanine is not an intermediate in pyruvic-oxime oxidation. Hydroxylamine and ammonia are also unlikely to be intermediates. Suspensions of resting Achromobacter sp. oxidize acetate and pyruvate readily, succinate after a short lag period, and fumarate very slowly. Malonate is not attacked. The evidence would indicate that pyruvic oxime is oxidized to pyruvate and nitrite, the pyruvate then undergoing further breakdown. The enzyme system responsible for the oxidation or pyruvic oxime is termed pyruvic oxime oxidase. NaN3 and NaCN markedly inhibit the activity of pyruvic oxime oxidase. Pyruvic oxime oxidation by suspensions of resting Achromobacter sp. is inhibited by the oximes of alpha-ketoglutaric acid, phenylpyruvic acid and arabinose. These oximes are apparently either feebly or not attacked by pyruvic oxime oxidase. The oxime of alpha-ketobutyric acid is also oxidized by washed suspensions of Aehromobacter sp., probably by the pyruvic oxime oxidase.