Effect of pH and ionic strength on hydrophobicity and electron donor and acceptor characteristics of Escherichia coli and Staphylococcus aureus

Abstract

Abstract- The aim of this study was to use M.A.T.S (Microbial adhesion to solvents) in order to examine the influence of pH and ionic strength on electron donor/electron accep-tor properties and surface hydrophobicity of Staphylococcus aureus ATCC 25923 and Escherichia coli AL52. Using this technique we found that the electron donor character for both strains was influenced by pH and ionic strength. This effect was more important for S. aureus. The electron acceptor was expressed for acidic pH. Regardless of pH, the electron donor character of S. aureus changed when the ionic strength increased from 10-3 M to 10-1 M. For E. coli, the electron donor character varied with ionic strength at pH 2, nevertheless, for other pH, this character was not influenced by ionic strength. Moreo-ver, surface hydrophobicity of two microbial cells surface was affected by pH and ionic strength. It was maximal at acidic pH and lower at basic pH for S. aureus. Regardless of pH and ionic strength, E. coli was hydrophilic. Key words: microbial cell surface, hydrophobicity, electron donor/electron acceptor pro-perties, pH, ionic strength, M.A.T.S.