The Production of Gluconic Acid and 2-Keto-Gluconic Acid from Glucose by Species of Pseudomonas and Phytomonas.

The production of ketogluconic acids from glucose by fermentation methods has been of particular interest to this Bureau as a means of extending the industrial utilization of agricultural products. Our investigations have led to the development of a rapid and efficient process for the production of 5-ketogluconic acid from glucose by Acetobacter suboxydans, as heretofore reported (Stubbs et al., 1940). However, we have not found it possible to conduct a fermentation with our strain of A. suboxydans on any substrate in such a manner that 2-ketogluconic acid is the major product, as has been reported by Bernhauer and Knobloch (1938). These authors found that a certain strain of A. suboxdans gave predominantly 2-ketogluconic acid when cultivated on gluconic acid salts, although when cultivated on a glucose substrate, 5-ketogluconic acid was the principal product. A more recent publication by Bernhauer et al. (1940) indicates that such results are dependent on the particular strain of A. suboxydars used, for a second strain tested by them yielded 5-ketogluconic acid when cultivated either on glucose or gluconates. Although we have not succeeded in producing 2-ketogluconic acid with A. suboxydans, we have found that this product can be very efficiently obtained from glucose by the action of members of a different genus of bacteria. An organism which appeared as a contaminant during an A. suboxydans fer-