Engineered coatings containing cyclic peptides from cyanobacteria delay the development of a stable macrofouling community

Biofouling-the adhesion of organisms and their byproducts to submerged surfaces-poses economic and environmental challenges, highlighting the need for sustainable antifouling solutions. This study reports a proof-of-concept investigation into the environmental compatibility and field validation of natural cyclic peptides portoamides A and B (Pam) as a bio-based antifouling alternative. Pam have demonstrated antifouling activity by inhibiting mussel larval settlement and disrupting biofilm formation. Herein, the antifouling performance of Pam-engineered coatings was evaluated through anti-settlement, anti-biofilm, as well as marine field tests. Lab-scale tests revealed that Pam-based coatings (0.7 wt%) effectively reduced biofilm thickness, surface coverage, and mussel larval settlement. Field trials showed that Pam-functionalized coating prototypes outperformed a commercial biocide in use (Econea®), delaying macrofouling community establishment and contributing to enhanced antifouling effectiveness. Overall, this work supports further development of antifouling engineered systems using Pam, representing a significant technological advance (from Technology Readiness Level 3 to 6) toward sustainable marine coating systems.