Studies on Transfer of Antiseptics to Microbes and their Toxic Effect

The adsorption of phenols such as phenol, o-cresol, thymol, o- and p-phenylphenol, guaiacol, eugenol, α- and β-naphthol on bakers' yeast cell was investigated in relation to their toxic effect on the yeast growth. It was found that a definite quantity of the adsorbed phenols is required in order to give a definite inhibiting effect, being independent of the kind of phenol, and it was concluded that the toxic effect depends upon the quantity of the adsorbed phenols. The adsorbed quantity required to inhibit the yeast growth for two days was 14_??_19 m-mol./ kg-cell in all cases of the phenols examined, and this value is in fairly good agreement with that obtained in cases of acid antiseptics and their esters (cf. Parts II, III and IV). The inhibiting mechanism of these phenols was assumed to be the same as in cases of acid antiseptics and their esters.