Selection of commercial hydrolytic enzymes with potential antifouling activity in marine environments

Abstract

In this work, the marine antifouling potential of some commercially available hydrolytic enzymes acting on the main constituents of extracellular polymeric substances (EPS) involved in bacterial biofilm formation was determined. The selected protease (i.e., alpha-chymotrypsin from bovine pancreas), carbohydrase (i.e., alpha-amylase from porcine pancreas) and lipase (from porcine pancreas) exhibited remarkable hydrolytic activities towards target macromolecules typically composing EPS under a wide range of pHs (6.5–9.0 for alpha-chymotrysin and alpha-amylase; 7.0–8.5 for the lipase) and temperatures (from 10 °C to 30 °C), as well as relevant half-lives (from about 2 weeks to about 2 months), in a marine synthetic water. The activity displayed by each enzyme was poorly affected by the co-presence of the other enzymes, thus indicating their suitability to be employed in combination. None of the enzymes was able to inhibit the formation of biofilm by an actual site marine microbial community when applied singly. However, a mixture of the same enzymes reduced biofilm formation by about 90% without affecting planktonic growth of the same microbial community. This indicates that multiple hydrolytic activities are required to efficiently prevent biofilm formation by complex microbial communities, and that the mixture of enzymes selected in this study has the potential to be employed as an environmental friendly antifouling agent in marine antifouling coatings.