evaluation of cationic micropeptides derived from the innate immune system as inhibitors of marine biofouling a series of 13 short synthetic amphiphilic cationic micropeptides derived from the antimicrobial ironbinding innate defence protein lactoferrin have been evaluated for their capacity to inhibit the marine fouling process the whole biofouling process was studied and microfouling organisms such as marine bacteria and microalgae were included as well as the macrofouling barnacle balanus improvisus in total 19 different marine fouling organisms 18 microfoulers and one macrofouler were included and both the adhesion and growth of the microfoulers were investigated it was shown that the majority of the peptides inhibited barnacle cyprid settlement via a reversible nontoxic mechanism with ic50 values as low as 05 g ml1 six peptides inhibited adhesion and growth of microorganisms two of these were particularly active against the microfoulers with micvalues ranging between 001 and 1 g ml1 which is comparable with the commercial reference antifoulant seanine