Change of cell membrane hydrophobicity in a bacterium tolerant to toxic alcohols

Abstract

An n-heptanol-tolerant bacterium, i.e., Pseudomonas putida No. 69-3, can be derived from an organic solvent sensitive bacterium with the ability to degrade dibenzothiophene by applying ultraviolet rays and exposing to n-heptanol, as reported previously. When the log P value of the alcohol used during cultivation was low, the quantity ratios of individual free fatty acids to the quantity of free fatty acids plus the fatty acids incorporated in lipids was high, the level of high molecular weight lipopolysaccharides was low, and the cell-surface membrane became hydrophobic. This suggests that when the bacterium was exposed to alcohols with low log P values, meaning ones that easily dissolve in water, the bacterium changed degrees of cell-surface hydrophobicity and adapted to the alcohols.Key words: Pseudomonas putida, organic solvent tolerance, fatty acid, lipopolysaccharide, cell-membrane hydrophobicity.