Antifouling strategy for marine transport efficiency in Nigeria: The isothiazolone option

Abstract

The sustainability of Nigerian maritime industry is threatened by drag and deterioration caused by biofilms on painted marine structures. The bacterial population of scrapings from twenty boat hulls on Ojo waterside shores, Lagos, Nigeria and the antibacterial activity of in-can isothiazolone biocide against the isolated biofilm bacteria were investigated. The disc diffusion technique using Mueller Hinton agar (MHA) media and sterile filter paper discs immersed into the biocides was employed. Bacterial population density of the scrapings ranged from 1.3 to 2.2 x 10^-5CFU/g. They were identified as Pseudomonas aeruginosa, Proteus mirabilis, and Staphylococcus aureus using the analytical profile index (API). All the isolates were susceptible to isothiazolone biocide with the highest inhibition zone of 24.75mm (P. mirabilis) and the lowest inhibition zone of 4.63mm (S. aureus). The MIC was observed as 15μl/ml (S. aureus), 5μl/ml (P. aeruginosa) and 5μl/ml (P. mirabilis) while MBC was 20μl/ml (S. aureus), 5 μl/ml (P. aeruginosa) and 15μl/ml (P. mirabilis). Results showed that isothiazolone biocide has broad spectrum antibacterial activity against bacterial biofilms on marine structures.

Keywords: Biofouling; boat; isothiazolone biocides; maritime industry; Nigeria