Effect of different Bacillus subtilis lipopeptides on surface hydrophobicity and adhesion of Bacillus cereus 98/4 spores to stainless steel and Teflon

Abstract

Various lipopeptides produced by Bacillus subtilis were examined for their ability to modify the surface hydrophobicity of two substrata, stainless steel (SS) and Teflon. These modifications were evaluated by water contact angle measurements. The effects depended on the lipopeptide, its concentration, and the tested substratum. Treatment of SS with different concentrations of surfactin S1 showed an increase of the hydrophobicity between 1 and 100 mg l⁻¹. On the same substratum, fengycin increased hydrophobicity up to its critical micelle concentration (6.25 mg l⁻¹). With higher concentrations of fengycin, hydrophobicity decreased. Surfactin, mycosubtilin, and iturin A decreased hydrophobicity on Teflon. The different effects of these three families of lipopeptides were related to their structural differences. A good correlation was shown between hydrophobicity modifications of surfaces and the attachment of B. cereus 98/4 spores. Enhancement in the hydrophobicity of the surfaces increased the number of adhering spores.

Keywords:

• biosurfactant
• lipopeptide
• surface properties
• adhesion
• Bacillus cereus
• spore

Acknowledgements

This work received financial support from the Université des Sciences et Technologies de Lille, the Région Nord – Pas de Calais (France), the “Ministère de l'Enseignement et de la Recherche” and from FEDER. Special thanks are due to S. Parent and J. Jacquemont for their valuable technical assistance and to J.S. Guez for mycosubtilin production.