Effective antifouling action of seaweed metabolite waste against marine foulers

Fouling on ships and in marine environments leads to adverse effects, including increased drag on the engine, elevated fuel consumption, and higher CO₂ emissions, all of which negatively impact the operational efficiency of the ship and worsen environmental pollution. To address these challenges, sustainable antifouling coatings derived from seaweed materials play a crucial role in mitigating fouling and providing long-lasting protection. Herein, the relationship between antifouling compounds derived from biological sources is examined through a combination of computational methods and in vitro experiments. A total of 100 compounds from both Laurencia obtusa and Acanthophora spicifera were computationally screened against Mytilus galvoprovinces (4CN8) and Megabalanus rosa (6LEK) target proteins. Thyrsiferol compound from Laurencia obtusa exhibited the maximum dock score (-8.6 kcal mol⁻¹), and Cholestaa-6, 22,24-Triene,4,4-Dimethyl compound from Acanthophora spicifera showed the highest dock score (-8.9 kcal mol⁻¹) against macro fouling protein. The docking study unveiled a range of dock scores indicating low to high inhibition, all associated with low toxicity effects. The in vitro study involved collecting two seaweed species using the Soxhlet extraction method, followed by antibacterial and antifouling assays against common fouling organisms. Methanol and ethanol extracts showed strong inhibitory activity, indicating the presence of bioactive compounds with significant antibacterial and antifouling effects. The primary component of Laurencia obtusa, which plays a major role in antifouling action, was identified through GC-MS as n-Hexadecanoic acid (19.340 %), while Acanthophora spicifera predominantly contained nonadecanoic acid (19.932 %).