Bioprospecting Novel Antifoulants and Anti-Biofilm Agents from Microbes

Abstract

Fouling on the surfaces of ships or other submerged structures results in corrosion, a decrease in hydrodynamic efficiency, transport of introduced pests, and many other problems worldwide. Fouling generally occurs in a predictable sequence, with colonization by bacteria and biofilm formation happening in hours to days followed by colonization of higher organisms such as barnacles, tube worms, and algae. Other than repeated cleaning of surfaces, by far the most common commercial approach to fouling control is to coat surfaces with antifouling paints that slowly release toxic compounds to the surface, deterring initial colonization of the surface by fouling organisms or killing newly settled foulers. Two major alternatives to heavy metal-based paints have been proposed. The first, which are commercially available, are the so-called nonstick or foul-release coatings. The second major class of alternatives to heavy metal-based paints are organic compounds, either synthetic or naturally derived. The later category includes the so-called natural antifoulants. The focus on natural antifoulants to date has primarily been on marine invertebrates and algae. This chapter addresses methodological limitations in the research of marine microbial defenses and the progress that is being made in this research field. The genus Pseudoalteromonas is common in the marine environment and is often isolated from living surfaces, as demonstrated by both traditional culturing methods and culture-independent techniques such as denaturing gradient gel electrophoresis. The chapter suggests that marine host organisms that lack their own chemical defense mechanisms may be colonized by antifouling-producing bacteria, such as Pseudoalteromonas species.