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

Abstract

Two compounds, 2-hydroxymyristic acid (HMA) and cis-9-oleic acid (COA), were isolated from a chloroform extract of the marine bacterium, Shewanella oneidensis SCH0402. In a spectrophotometerbased chemotaxis assay, HMA completely eliminated the optical density (OD) of Alteromonas marina SCH0401 and Bacillus atrophaeus SCH0408, motile, fouling bacteria, at 100 and 1000 lg ml -1 , respectively. COA similarly decreased the OD of A. marina and B. atrophaeus by 100% at 1000 lg ml -1 . The commercially available, highly toxic anti-fouling compound, tributyltin oxide (TBTO) never reduced the OD of the target bacteria by 100% even at higher concentration. Instead, all the test bacterial cells were killed at higher than 1000 lg ml -1 of concentration. Both HMA and COA inhibited germination of Ulva pertusa spores completely at 10 and 100 lg ml -1 , respectively, while TBTO inhibited germination at 0.01 lg ml -1 . However, in field assays, both HMA and COA showed antifouling activities as potent as TBTO against a wide range of fouling organisms, including micro-and macro-algae, barnacles, and mussels. The average fouling coverage on the surface of the control panel was 93 ± 6% after 1.5 years but no fouling was observed on the surface of the test panel onto which each compound was applied separately. Thus, bacterial repellent compounds can be used as substitutes for potent toxic anti-fouling compounds, resulting in higher standards of environmental safety without loss of anti-fouling performance.

Mini-review: Inhibition of biofouling by marine microorganisms

“…These compounds inhibited settlement of zoospores of U. pertusa and the diatom Navicula annexa. The marine bacterium Shewanella oneidensis SCH0402 produced 2-hydroxymyristic acid and cis-9-oleic acid, which inhibited germination of spores of U. pertusa (Bhattarai et al 2007). In field bioassays, these compounds were as efficient as the toxic AF compound tributyltin oxide.…”

Comparative effects of indole derivatives as antifouling agents on the growth of two marine diatom species

“…More importantly, antifouling coatings containing 10% 9-Z-oleic acid were able to reduce the attachment of micro-and macro-foulers for about 1.5 years. [28,29] Alkylated butenolides were also a class of metabolites from marine bacteria Streptomyces sp., which showed potent antifouling activity against the larvae of fouling organisms with very weak toxicity. The study of structure-activity relationships revealed that the 2-furanone ring was essential for the activity and lipophilicity obviously influenced their antifouling activities.…”

Glycoglycerolipids Isolated from Marine DerivedStreptomyces coelescensPK206-15

“…Palmitic acid, isolated from the brown alga Sargussum muticum, and 2-hydroxymyristic acid and (9Z)-oleic acid, derived from the marine bacterium Shewanella oneidensis, inhibit spores of U. pertusa. 39,40) In the present experiment, the antifouling activity of commercial free fatty acids was determined. It showed less activity than the glycoglycerolipids, suggesting that glycolycerolipids are responsible for the antifouling activity, not the fatty acids alone.…”