1990 Volume 31 Issue 5 Pages 414-419_1
The relation between bactericidal action of aliphatic alcohols, such as ethanol, propanol and butanol, and their thermal properties was studied using differential scanning calorimetry (DSC) over a wide range of concentrations to investigate the effect of alcohols on bacteria.
In parallel with the appearance of a new endothermic peak in DSC thermograms during warming form -140°C to 20°C, ethanol solution showed a considerably increased bactericidal effect on Escherichia coli and Staphylococcus aureus at volume concentrations up to 30-40% (V/V%). Increasing the concentration of ethanol led to characteristic interaction between water and alcohol, which seemed to be related to the bactericidal action.
On the other hand, 1-butanol, 2-butanol and iso-butanol, but not t-butanol, had bactericidal action with no such new peak in DSC thermograms. Longer-chain alcohols, such as butanol showed an apparent relationship of hydrophobicity to the potency of their bactericidal action.
In conclusion, it is suggested that the effects of short-chain alcohols such as ethanol are dominated by interaction of their hydroxyl function with that of water. In the case of longer-chain alcohols, such as butanol, the hydrophobic nature of the hydrocarbon tail seems to dominate their actions.
