Anti-microfouling activities in extracts of two invasive algae:Grateloupia turuturuandSargassum muticum

Marine macroalgae are particularly prone to epiphytism. The colonisation of their surface may lead to severe perturbations and sometimes to the death of the host. To protect themselves against settling and/or competing organisms, many algae have developed defences against fouling by producing a wide variety of chemically active metabolites. The goal of this study was to investigate potential anti-microfouling activities of two introduced algal species from the Brittany coast (France),Sargassum muticum(Phaeophyceae) andGrateloupia turuturu(Rhodophyceae). Thus, a complete study of the antimicrobial activities of extracts (aqueous, acetone, chloroform, dichloromethane, diethyl-ether, ethyl acetate, ethanol 96°, hexane and methanol) fromS. muticumandG. turuturuagainst marine fouling bacteria (5 strains), fungi (5 strains) and biofilm-associated microphytobenthic strains (5) were performed. The most active extract ofG. turuturuwas the dichloromethane fraction, while the chloroform extract fromS. muticumshowed some good results. Our data suggest that these macroalgae can provide useful compounds or templates for industrial anti-microfouling applications.