Interactions des bactéries marines responsables de la formation des biosalissures avec des matériaux biospécifiques

The immersion of a material in a marine environment automatically results in forming a biological veil which develops into biofouling. Biofouling is responsible for many problems that occur on immerged structures. Marine bacteria are strongly involved in biofouling and specific studies are aiming at limiting their adhesion to the surface of immerged materials. The Laboratoire de Recherches sur les Macromolécules (Macromolecule Research Laboratory) has demonstrated that modulating or inhibiting human commensal bacteria with biospecific statistical copolymers is possible. The goal of our research has been to identify statistical copolymers capable of inhibiting marine bacteria adhesions and therefore reduce marine biofilm formation. In order to do so, two Vibrio splerididus bacterial strains (D01) and D41 (still being identified), both pioneer in biofilm formation, have been selected and a study has been started in order to define bacterial culture conditions, metabolical marking with tritiated thymidme and adhesion on material surfaces. With statistical copolymers, bacteria interact with surfaces via mediators, thus increasing bacterial adhesion. Contrary to our starting hypothesis which was to select statistical copolymers capable of inhibiting adhesion, we found out that these copolymers stimulate marine bacteria adhesion. Along the same line, studies were conducted on demonstration materials with hydrophobic (PMMA, PS, PVC, AC) and hydrophilic (glass, PHEMA, cellulose) properties. Regarding bacterial adhesion to demonstration materials, PMMA in human plasma conditions shows significant differences in regards to human commensal bacteria adhesion as previously studied at the laboratory. This enables us to first conclude that marine bacteria behave differently than commensal bacteria. We also demonstrated that bacteria adhesion on glass, PHEMA and cellulose is very low and non mediated, regardless of the environment used. This study has allowed us to better understand the mechanisms leading to marine bacteria adhesion on surfaces. It will allow us to propose the hypothesis that reducing bacteria adhesion can be done by increasing the hydrophilic properties of immerged surfaces.