A novel alternative fate for shrimp fishery wastes as active ingredients in ecofriendly antifouling paints

Abstract

This study addresses two environmental issues: the fate of fisheries organic wastes and the marine biofouling control. Marine biofouling continues to pose a significant environmental and economic burden, with existing solutions often being environmentally toxic or prohibitively expensive. Natural products, such as enzymes, have emerged as promising alternatives. Shrimp processing wastes are usually dumped to the environment, although they constitute an important source of marine enzymes. In this context, the present study investigates the potential of enzymatic extract derived from shrimp processing waste as an antifouling agent. We focused on the performance and stability of proteolytic enzymes within the extract under various conditions: exposure to seawater (static and dynamic) over time, and resistance to organic solvents. Additionally, we explored field trials using antifouling paints formulated with shrimp extract and we investigated a versatile and simple technology for extract immobilization. The results demonstrate that proteolytic activity in the shrimp extract remained stable over time in seawater and when exposed to organic solvents. Paints containing this extract completely inhibited macrofouling attachment for 7 months. Interestingly, control panels with deactivated enzymes exhibited macroalgae colonization but also showed reduced macroinvertebrate attachment. This suggests that additional compounds within the extract may have antifouling properties. We successfully produced nanocapsules of alginate-chitosan containing the shrimp extract using electrohydrodynamic atomization. While these nanocapsules show promise, further optimization is required. Overall, this study presents encouraging findings for the use of shrimp waste extract in antifouling paint formulations. This approach offers a potentially low-cost and environmentally friendly solution to the biofouling problem.