培養基のpHと細菌発育について

Abstract

In order to explain the effect on the enzyme activities of bacteria to glucose and succinate on the reaction by resting cells under different pH from that of culture media, the author observed the enzyme activities of Sal. 57 S under a various pH of reaction media by means of conventional WARBURG's manometer. Sal. 57 S used in this study were cultured at the pH of 5.4, 7.2 and 8.3 respectively. The effect on the enzyme activity by a sudden change of pH during the reaction was also studied. The results obtained were as follows.1) Concerns to the enzyme activity to glucose, the bacterial cells showed an adaptation to the different pH of reaction media by short time incubation of resting cells in that media and gave the proper reaction rate to the pH of reaction media. By the change of the pH of reaction media to the identical pH of culture media during the reaction, this adaptation to the reaction media was gradually lost and the reaction rate approached to the rate found at the same pH as growth media. But the bacterial cells cultured at the pH of 5.4 adapted to the pH of reaction media in alkaline by long time incubation in that and the reaction rate retained for long in spite of the change of pH to the pH of growth media.2) In the case of the activity to succinate, the bacterial cells did not show an adaptation to the different pH of reaction media by such incubation as above. The enzyme activity of either culture was found to be highest at the pH of 5.4.