ACTIONS OF SURFACE ACTIVE AGENTS UPON LACTIC ACID BACTERIA. THE GERMICIDAL ACTION AND THE EFFECT ON THE PERMEABILITY

Abstract

The mechanism of the germicidal action of surface active agents was studied. It was observed that surfactants have the following action on intact cells of lactic acid bacteria; (1) accelerate the penetration of lactate into the intact cells, (2) liberate the free amino acids from internal environment, (3) prevent the penetration of glucose and gluconate, which are metabolic sources of energy for the cell.
Some remarkable parallelisms between these actions and their germicidal power were observed.
When the cells which had changed in the permeability and been unable to grow by binding with CTAB were washed with the oppositely charged surfactant A-1. The permeability of the cells reversed to that of the intact cells and the cells grew again.
From these results, it is supposed that the germicidal action of surfactants depends on the action to immediately bind with the cells changing the permeability to unsuitable one for growth.
Moreover, anionic surface active agents inhibit lactic dehydrogenase and glucose-6-phosphate dehydrogenase. It seems likely that the germicidal effect of anionics depends not only on the action to change the permeability of the cells but also on the action to denaturate the cell proteins.