Antibacterial properties and possible action mechanism of chelating peptides-zinc nanocomposite against Escherichia coli

Octopus scraps, as a kind of marine waste, have drawn much attention due to its biological values. Amino groups and carboxyl groups of octopus scraps peptides (OSP) chelated with Zn2+ formed OSP-Zn by Zn-N and Zn-O covalent bonds. The aggregation state of OSP had been changed and the typical particle diameter of OSP transformed from 104.74 nm to 147.36 nm after chelating with zinc. The chelate OSP-Zn showed notably antimicrobial ability towards Escherichia coli (E. coli). Moreover, the antibacterial mechanism of OSP-Zn against E. coli might be explained by the pathway of damaging cell membrane structure and oxidative stress-mediated apoptosis. It also suggests that OSP-Zn could inhibit the growth of the dominant spoilage bacteria of Penaeus vannamei and exhibit a good preservative effect. Our work illuminates the synergic effect of OSP and Zn complexes for the first time, supporting the potential application of OSP-Zn chelate as a natural bacteriostatic agent in the food or pharmaceutical industry.