The oxidation of d-quercitol by Acetobacter suboxydans.

The oxidation was carried out on a preparative scale with resting bacteria in the presence of oxygen by the technique described in the preceding paper (2). Oxygen uptake under these conditions ceased when about 1.3 atoms of oxygen had been taken up per molecule of d-quercitol. The addition of phenylhydrazine to the reaction mixture resulted in the deposition of a dextrorotatory, crystalline, yellow compound, having the analytical composition of the bisphenylhydrazone of a diketo quercitol. The yield was 33 per cent of the theoretical, based on the amount of oxygen consumed. The low recovery of bisphenylhydrazone and the incomplete oxidation (measured by the oxygen uptake) seem to indicate that the attack on a large portion of the substrate stopped with the formation of an intermediate monoketo compound. This finding is in keeping with observations reported previously (l), which showed that the rate of the first oxidation step was considerably greater than that of the second, and that with a smaller quantity of bacteria the total oxygen uptake amounted to only 1 atom per molecule of substrate. Attempts at the isolation from the reaction mixture of the phenylhydrazone of a monoketo compound were, however, not successful. The absorption spectrum of the bisphenylhydrazone reproduced in Fig. 1