Test systems for determining antifouling coating efficacy using on-line detection of bioluminescence and fluorescence in a laminar-flow environment

Abstract

Test systems have been developed which enable the evaluation of bacterial biofilm formation and metabolic activity under conditions simulating those of in situ environments. A series of laminar-flow adhesion cells were constructed with provisions for on-line, non-destructive measurements of bioluminescence, fluorescence, open circuit potential, and pO 2 to monitor colonization and succession as influenced by a systematic change in bulk-phase and substratum conditions. Bioluminescence by biofilms of the bioluminescent marine bacterium, Vibrio harveyi was utilized as an endpoint for adhesion in evaluations of antifouling (AF) ship hull coatings. Resistance to colonization of V. harveyi was noted in the order of F-121 (Navy > BRA 640 (IP) > 15% DNP. Statistically significant (p < 0.05) correlations were obtained between bioluminescent, viable, and direct bacteria counts. Tryptophane was used as a biomass marker in fluorometric measurements of V. harveyi biofilms. These methods enabled on-line evaluations of biofilm formation and AF coating efficacy.