The Fermentation of Acetyl-Methyl-Carbinol by the Escherichia-Aerobacter Group and Its Significance in the Voges-Proskauer Reaction.

The ability of certain members of the Aerobacter genus to ferment acetyl-methyl-carbinol is indicated by their transitory Voges-Proskauer reactions. These strains produce acetylmethyl-carbinol from glucose and, consequently, yield positive Voges-Proskauer reactions after incubation for from one to three days in Clark and Lubs' medium (1915). When incubation is continued for longer periods, however, the reactions become negative. Paine (1927), and Williams and Morrow (1928) showed that these bacteria "destroyed" the acetyl-methylcarbinol which was present in filtrates of young cultures. In their experiments, the sterile filtrates were inoculated with the cultures to be tested and, after various periods of incubation, the presence or absence of acetyl-methyl-carbinol was determined by the Voges-Proskauer method. A negative reaction was considered as evidence that the acetyl-methyl-carbinol had been "destroyed." Supplementary experiments showed that the negative reactions were not due to an exhaustion of peptone. Williams and Morrow concluded, therefore, that "it seems probable that the compound serves as a source of carbon." Although the work just cited showed that acetyl-methylcarbinol is "destroyed" by certain members of the Escherichia-