This study examined how four short-chain alcohols (methanol, ethanol, propanol, and butanol) affect bacterial attachment of a marine Pseudomonas species to polystyrene surfaces. At concentrations of 0.2-2.0%, certain alcohols increased attachment to tissue culture dishes (ethanol at 0.2-0.5%, propanol at 0.2, 1.5-2.0%, and butanol at 1.0%), while methanol consistently decreased attachment. Pre-incubation of bacteria with alcohols produced different effects than exposure during attachment. The researchers measured surface tension and contact angles to understand the physicochemical mechanisms involved. They found a relationship between bacterial attachment and the surface tension of the medium, with minimum attachment occurring at surface tension values of 64-69 mN m⁻¹. Notably, ethanol, propanol, and butanol increased bacterial respiration rates without supporting growth, suggesting these alcohols modify cell physiology and surface properties. The increased attachment to the more hydrophilic tissue culture dishes coincided with increased respiration, implicating changes in cell surface characteristics rather than simple passive adsorption.

Key findings

• Methanol progressively decreased bacterial attachment to both surfaces, while ethanol, propanol, and butanol showed complex concentration-dependent effects with increases in attachment to tissue culture dishes at specific concentrations
• Minimum bacterial attachment occurred at medium surface tension values of 64-69 mN m⁻¹ for both hydrophobic and hydrophilic polystyrene surfaces
• Ethanol, propanol, and butanol increased oxygen uptake rates sustained over time, without supporting bacterial growth, suggesting alcohols induce metabolic stress responses
• Pre-incubation effects differed from attachment in the presence of alcohols, indicating both physiological and medium properties contribute to attachment changes
• Substrate surface properties influenced attachment patterns, with greater bacterial attachment to the more hydrophilic tissue culture dishes than polystyrene petri dishes