Isolation of antifouling compounds from the marine bacterium, Shewanella oneidensis SCH0402

Abstract

In search of eco friendly antifouling (AF) compounds, two bioactive secondary metabolites, 2-hydroxy myristic acid and cis-9-oleic acid, were isolated and characterized from the marine bacterium, Shewanella oneidensis. The test compounds showed significant AF activities in both laboratory and field assays. These compounds repelled the test marine bacteria, Alteromonas marina, Bacillus atrophaeus, Roseobacter gallaeciensis and Shewanella oneidensis, and spores of the green alga, Ulva pertusa more effectively than the commercial AF agent, tributyltin oxide, TBTO. However, the toxic effects of the test chemicals against the test organisms were weaker than TBTO. The minimum inhibitory concentrations of the test compounds were more than 1000 ？g disk-1 against the test bacteria except A. marina, while TBTO showed its MIC values less than 0.2 ？g disk-1 against all test species. Similarly, Ulva spores did not lose their motility at 100 ？gml-1 level of concentrations of the test chemicals. In field assay, the test chemicals showed perfect results of AF activity by showing cent percent capacity of fouling resistance during the experimental period of ten months. The overall results indicated that these test compounds repelled the fouling organisms without killing or allowed to attach loosely and, later, they were washed by the minor waves of moving water.