Influence of some natural compounds on freshwater microfoulants

The antifouling properties of five natural compounds (poly-alkyl pyridinium salts - pAPS. Ceramium botryocarpum extract - CBE, zosteric acid - ZA, capsaicin - CS and cinnamaldehyde - CI) were tested against mixed and isolated freshwater biofilm microbial components, in laboratory conditions. These active natural agents can be extracted from marine (Reniera sarai, Zostera marina, Ceramium botryocarpum) or terrestrial (chilli pepper, cinnamon) natural sources and for some of them (ZA, CS and CI), the corresponding chemical compounds can be synthesized as well. The evaluation of their efficacy in liquid and solid cultural medium, using serial dilution and diffusion method. was performed. The most efficient antibiofouling agents (ABAs) seems to be pAPS and CI at all tested concentrations. ZA exhibited a contrary behaviour with respect to the others inhibitors, being less efficient at he highest concentrations. However, most of the ABAs tested are efficient against cyanobacteria rather than algae, and only CI showed a inhibitor effect against fungi as well.