Antifouling activity of Malaysian green seaweed and its isolated non-polar compound.

Marine natural products especially seaweeds have gained much attention to combat biofouling. was determined for its antifouling activity and characterized the isolated non-polar metabolite involved. The methanolic crude extract (MCE) of was screened using crystal violet assay against biofilm-forming bacteria and was further tested on laboratory and field tests. Then, it was fractionated and isolated using Liquid-Liquid Fractionation (LLE) and Column Chromatography (CC). The isolated compound was characterized using Liquid Chromatography-Mass Spectrometry (LC-MS), Nuclear Magnetic Resonance (NMR), and Fourier Transform-Infrared Spectroscopy (FTIR). The current study showed that the growth of biofilm produced by was inhibited by MCE at concentrations of 0.0156 mg/mL. The laboratory test indicated UL5% demonstrated a higher bacterial reduction of bacterial colonies with 1.903 × 10 CFU/mL better than blank paint. According to the field test, crude panels of UL5% were successful in reducing the settlement of fouling organisms due to less macrofouler growth compared to blank paint. The isolated compound A4 was identified as hexadecanoic acid (CHO) through NMR with a molecular mass of 256 g/mol detected using LC-MS. The characterization through FTIR obtained functional groups consisting of CH, CH, C=O, and OH. Therefore, produced hexadecanoic acid as one of the promising compounds from the seaweed group as an eco-friendly antifouling agent.