Zinc Oxide Nanoparticles—Synthesis, Characterization and Antibacterial Activity

The ever increasing demand for seafood has lead aquaculture farmers to resort to intensive culture practices leading to stress of the animals and enhanced susceptibility to diseases. Vibriosis is one of the most prevalent bacterial diseases. Antibacterial activity of zinc oxide nanoparticles was tested in this study. Zinc oxide nanoparticles were synthesised by chemical precipitation method using Zinc acetate and varying concentrations (0.1%, 0.5%, 1%) of soluble starch and compared with the commercial ZnO nanoparticles for the inhibition of V. anguillarum pathogenic bacteria in aquaculture environment. The synthesized ZnO nanoparticles were confirmed using X-ray Diffraction analysis and the average size of the particles was 50 nm. Field Emission-Scanning Electron Microscopy images showed hexagonal morphology of the synthesised nano-ZnO. Flourescence Transform Infrared Spectroscopy analysis confirmed binding of starch to nano-ZnO. Energy dispersive X-ray analysis determined the elemental composition of nano-ZnO and Ultraviolet-Visible spectroscopy analysis revealed significant blue shift and ascertained the stability of the particles. Synthesized ZnO nanoparticles had higher bactericidal activity than commercial. Antibacterial assay revealed that nano-ZnO synthesised using 0.5% starch had the most efficient antibacterial activity against V. anguillarum with MIC of 30 μg/ml and MBC of 40 μg/ml and zone of inhibition of 15 mm. SEM image of V. anguillarum treated with and without ZnO nanoparticles confirmed the bacterial cell damage by ZnO nanoparticles. The results concluded that nano-ZnO is an effective bactericidal agent on V. anguillarum and can be used in aquaculture to effectively combat bacterial diseases.