Acetic Acid Production from Ethanol by Fluorescent Pseudomonads.

Apart from the observation by Alsberg (1911) that gluconic acid is produced from glucose by Phytomonas savastanoi, the oxidative metabolism of fluorescent pseudomonads has received little attention until very recently. For the most part it has been tacitly assumed that these org Ims, by virtue of their obligately aerobic nature, carry out a complete mineralization of organic substrates (den Dooren de Jong, 1926). However, the researches of Pervozvanski (1939a, 1939b), followed by those of Lockwood et al. (1941, 1946), have established the unexpected fact that the dissimilation of monosaccharides by the majority of fluorescent pseudomonads is accompanied by the production and accumulation of the corresponding hexonic or pentonic acids in large amounts. Some strains when acting on glucose also carry the oxidation further to 2-ketogluconic acid (Pervozvanski 1939a, Lockwood et al. 1941) and a-ketoglutaric acid (Lockwood and Stodola, 1946). The failure of all previous investigators except Alsberg to observe these phenomena may be ascribed to the use of weakly buffered and insufficiently aerated media (e.g., the customary tubes of carbohydrate broth), since acidity and poor oxygen supply are both limiting factors for the transformations in question. The oxidation of monosaccharides to the corresponding -onic acids is a pattern of biochemical behavior that occurs elsewhere among bacteria, so far as is at present known, only in the Acetobacter group. Coupled with the frequently overlooked morphological similarities, it serves, as Vaughn (1942) has pointed out, to indicate a close relationship between the genera Acetobacter and Pseudomonas. Consequently it seemed of interest to find out whether the primary biochemical characteristic of the acetic acid bacteria, namely the oxidation of ethanol to acetic acid, might not also exist in the genus Pseudomonas.