As reported in the previous paper, it has been demonstrated that the acceleration of O(2)-consumption is greatest in the case of the substrate glucose, while the interaction likewise seems to occur in the case of RQ. Moreover, since if being evident that the RQ value parallels with the production of acetoin, the present experimcnt has been conducted in order to trace the mechanism involved in the production of pyruvate and acetoin. Bacteria used: E. coli communis, A. aerogenes, Staphylococcus albus, and Staphylococcus aureus. Substrates: glucose, pyruvate, lactate, succinate, and acetate.
Inhibiting agents: DNP and NaN(3). 1. In the case of the substrate glucose, an interaction has been found to be involved in the production of acetoin, and its adequate pH seems to be 5.8-7.2. 2. The acetoin production in. the case with the use of the bacteria in the process of growth, has been nearly the same as that in the case with resting cells; and that with A. aerogenes especially pronounced. 3. In the case of the substrate pyruvate, hardly no acetoin production can be recognized. 4. In the case of the combination of E. coli with Staph. albus, which is cooperative in the acetoin production, it seems that acetoin is produced by E. coli utilizing of the decomposition products of glucose produced by albus. As for the combination of A. aerogenes with Staph. albus, it appears to be possible to assume that in the decomposition of glucose by A. aerogenes, the accumulation of pyruvate and other acids results in the lowering of pH so that acetoin production capacity of Staph. albus is activated. On the other hand, in the inhibitory combination of E. coli with Staph. anreus, it appears that E. coli might consume acetoin produced in the decomposition of glucose by Staph. aureus.