Modelling and optimization of phlorotannin extraction from Stoechospermum marginatum using response surface methodology and evaluating its activity against marine microfouling bacteria

The detrimental effects of synthetic antifouling ingredients has underscored the necessity for the development of eco-friendly antifouling compounds. Phlorotannins are secondary metabolites biosynthesized exclusively in brown seaweeds with a potential as an antifouling compound. This study optimized the extraction of phlorotannins from Stoechospermum marginatum using Box–Behnken design of response surface methodology and evaluated its potential for antifouling activity against marine microfouling bacteria isolated from the hull of fishing boat. Based on biofilm formation index, 13 bacterial isolates identified by 16S rRNA sequencing were found to have the ability to form biofilm in the initial stage in biofouling. The conditions that produced the highest phlorotannin content of 2.75 ± 0.02 mg of phloroglucinol equivalents/g are as follows: ethanol concentration of 78.6