New environmental-friendly approaches against detrimental biofilms

For decades, abatement of microbial growth has commonly been achieved by applying biocides to surfaces. In recent years impeding environmental regulations both in European Countries and elsewhere have severely restricyed the use of biocides. The concern about the use of biocides is that eventually they are released into the environment, and because they are generally not specifically targeted against biodeteriorating microorganisms, they are potentially dangerous for human health and the environment. In addition, organic biocides might act as nutrients, and therefore they must be carefully used. Finally, killed cell might provide nutrients for subsequent colonization, and therefore leaving dead cells on the surface is not advisable. Some environmnetally-friendly alternatives have been recently proposed (Flemming et al., 2006). Natural non toxic compounds represent an attractive strategy. Such antifouling compounds have been isolated mainly from marine organisms which are not colonized by microorganims. An interesting antifoulant agent is zosteric acid (p-sulfoxycinnamic acid), a natural extract from the ellgrass Zostera marina that prevents biofouling by some organisms, such as algae, barnacles, and tubeworms, at non toxic concentrations (Barrios et al., 2005). Capsaicin (8-methyl-N-vanillyl-6-nonamide), a pungent compound of the hot peppers, the fruit of the Capsicum plant, is considered by many researchers to be a compound able to prevent the growth of various bacteria, including Pseudomonas and Bacillus spp. (Molina-Torres et al., 1990; Dorantes et al., 2000). The main goal of our research has been the development of this innovative, green and cost-effective technology for the prevention of detrimental biofilms. The results obtained by us so far with zosteric acid and the synthetic analogue of capseicin indicate that indeed thistechnology may be a powerful tool (Cappitelli et al., 2006).