EVALUATING THE POTENTIAL OF ZOSTERIC ACID AND CAPSAICIN FOR USE AS NATURAL PRODUCT ANTIFOULANTS

iii The undesired deposition of cells on a surface and the subsequent formation of a cell layer (biofilm) are called biofouling. Biofouling on the hulls of vessels adversely affects both fuel consumption and maximum attainable speeds. Traditional antifouling paints containing toxic organotin species or cupric oxide are highly effective in controlling biofouling, but pose severe environmental concerns. Alternative non-toxic antifouling coatings need to be sought. The main objective of this research was to study the antifouling performance of two natural product antifoulants (NPAs), capsaicin and zosteric acid. Two freshwater bacteria, isolated Lake Erie (LE) bacteria and Pseudomonas putida (Pp), as well as two marine bacteria Vibrio parahaemolyticus (Vp) and Vibrio natriegens (Vn) were applied as the target antifouling bacteria species. Microtox assay indicated that the 5min-EC50 of capsaicin and zosteric acid were 11.75±1.02 mg/L and 442 ±100 mg/L, respectively. The static toxic assessments showed the EC50 of capsaicin and zosteric acid to be 10-23 mg/L and 240-380 mg/L, respectivel