Studies on the Bacterial Metabolism by Means of Oxidation-Reduction Potential Ⅰ: Oxidation-Reduction Potential in the Culture Media of Salmonella typhi

In order to study some physiological aspacts of bacteria, using Sal. typhi 57S as the test organism, the author measured the oxidation-reduction potential of the culture media with the lapse time. Salt solution, bouillon and M/50 phosphate buffer were used as the fundamental culture media, and lactate and glucose as the substrates. The results were as follows: 1) The potential of the liquid media of Sal. typhi 57S is lower in longer time culture. By separation of bactera, this potential rapidly rises by about 60 to 70 % , and then becomes stable, though still shows the tendency of some rise. By re-pouring the separated bacteria into the original culture media, the potential falls again, and this fall is generally milder when the first culture time is shorter. 2) There are a symmetrical correlation between the increasing rate of growing bacteria and the rising rate of potential of the culture media by separation of bacteria. 3) In a medium, in which a collodion membrane is placed to separate the bacteria-containing and non-containing part, the fall of potential is more marked in the part far from the bacteria-containing part, and, on the contrary, the potential of the bacteria-containing part shows a rising tendency. This phenomenon is marked when the two parts are separated by cellophane or bladder membrane, and not so marked by filter paper