Antibiotic from the marine environment with antimicrobial fouling activity

The degradation in performance of submerged marine structures through their colonization by micro- and macrobiota is well known. Historically, toxic surface coatings have been used to control both types of fouling. Legislative requirements worldwide now require alternative non- or minimally toxic coatings to be used. Here we report on the potential for synthetic 2-pentyl-4-quinolinol (PQ), an antibiotic from an Alteromonas sp., as a candidate antifoulant. Hundred micromolar PQ reduces the growth of four marine diatoms that usually grow as biofilms. Furthermore, PQ inhibits the initial adhesive process in Amphora coffeaeformis in a logarithmic dose-dependent manner, but not the adhesion of a Navicula sp., indicating differing adhesive processes in these two diatoms. Treatment of established biofilms with PQ causes a rapid and complete loss of motility in both Amphora and Navicula and eventually, as seen by Sytox Green staining, cell death, and lysis. We conclude that PQ, or one of its chemical analogues, holds promise as an antifoulant molecule for inclusion in marine surface coating.