This paper reports a comparison of the antibacterial properties of copper-amino acids chelates and copper nanoparticles against Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. These copper-amino acids chelates were synthesized by using a soybean aqueous extract and copper nanoparticles were produced using as a starting material the copper-amino acids chelates species. The antibacterial activity of the samples was evaluated by using the standard microdilution method (CLSI M100-S25 January 2015). In the antibacterial activity assays copper ions and copper-EDTA chelates were included as references, so that copper-amino acids chelates can be particularly suitable for acting as an antibacterial agent, so they are excellent candidates for specific applications. Additionally, to confirm the antimicrobial mechanism on bacterial cells, MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) was carried out. A significant enhanced antimicrobial activity and a specific strain were found for copper chelates over E. faecalis. Its results would eventually lead to better utilization of copper-amino acids chelate for specific application where copper nanoparticles can be not used.

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Due to the concern to find an alternative to reduce the colonization (microfouling and macrofouling) or the biocorrosion of surfaces submerged for long periods in water, we evaluated the antifouling activity of a commercial paint added with silver nanoparticles (AgNP’s) and copper nanoparticles (CuNP’s), beside copper-soybean chelate, by electrolytic synthesis, using them in low concentrations (6.94E − 04 mg Ag g−1 paint, 9.07E − 03 mg Cu g−1 paint, and 1.14E − 02 mg Cu g−1 paint, respectively). The test for paint samples was carried out by JIS Z2801-ISO 22196 for periods of initial time, 6 months, and 12 months, against three bacterial strains of marine origin, Bacillus subtilis, Bacillus pumilus, and Bacillus altitudinis. It was possible to demonstrate, according to the standard, that the sample with the greatest antimicrobial activity was the copper-soybean chelate against two of the three strains studied (B. pumilus with R = 2.11 and B. subtilis with R = 2.41), which represents more than 99% of bacterial inhibition. Therefore, we considered a novel option for inhibiting bacterial growth with nanoparticles as antifouling additives.