Lichenysin-geminal amino acid-based surfactants: Synergistic action of an unconventional antimicrobial mixture

Abstract

Recently it has been demonstrated that catanionic mixtures of oppositely charged surfactants have improved physicochemical-biological properties compared to the individual components. Isotherms of mixtures of an anionic biosurfactant (lichenysin) and a cationic aminoacid surfactant (C-3(LA)(2)) indicate a strong interaction suggesting the formation of a new 'pseudo-surfactant'. The antimicrobial properties of the mixture lichenysin and C-3(LA)(2) M80:20, indicate a synergistic effect of the components. The mechanism of action on the bacterial envelope was assessed by flow cytometry and Transmission Electron Microscopy. (C) 2016 Elsevier B.V. All rights reserved. Keywords: Antimicrobial properties; Arginine; Escherichia coli; Flow cytometry; Gemini surfactants; Lichenysin; Listeria nonocytogenes; Potassium leakage; Transmission electron microscopy.