ATTIVITÀ ANTIBIOFILM E ANTIFOULING DI UN POLISACCARIDE PRODOTTO DA AGARDHIELLA SUBULATA (RHODOPHYTA)

In this study, in an ongoing screening for novel environment-friendly anti-biofouling molecules, the polysaccharide (κ-carrageenan), extracted from the invasive macroalga Agardhiella subulata (Rhodophyta), collected from Lake of Ganzirri (Messina, Italy), was evaluated for its effects on biofilm formation of pathogens relevant in aquaculture and human health. Without exerting any antibacterial activity, the polysaccharide reduced the biofilm formation by both Gram-positive and Gram-negative bacteria in a dose-dependent manner (100-400 µg/mL). As assessed by the surface-coating assay and the microbial affinity to hydrocarbons, the polysaccharide was able to inhibit the early bacterial adhesion to polystyrene surfaces, modifying their cell-surface properties in terms of charges and hydrophobicity. Furthermore, the polysaccharide showed high emulsifying activity (E24 up to 70%). As not toxic compound, the algal extract could be proposed as antiadhesive to prevent biofilms.