Green synthesis of silver nanoparticles and its bactericidal effects against aquaculture pathogens

With the development of aquaculture, far more attention has been paid to safety in fish drugs usage. In order to find alternatives to antibiotics, silver nanoparticles (AgNPs) were synthesized using extracts of Ginkgo leaves with AgNO₃ in this study. The synthesized silver nanoparticles were characterized by UV-Visible spectrophotometer, transmission electron microscope and X ray diffraction spectrum. The antibacterial efficacy was assessed against Staphylococcus aurous, Escherichia coli and common bacterial pathogens in aquacuture including Edwardsiella tarda and Aeromonas hydrophila, by using cylinder plate method, broth macrodilution method and bacteriostasis kinetic experiments. The results showed that the absorbance maximum was observed at 460 nm corresponding to the plasmon absorbance of the AgNPs. Transmission electron microscope revealed that the AgNPs had an average size below 10 nm.The X-Ray Diffraction (XRD) spectrum of the nanoparticles confirmed the formation of metallic silver.The AgNPs synthesised in this research exhibited good antibacterial efficacy against the test pathogens. This investigation demonstrated that the green synthesis of AgNps with leaves of Ginkgo biloba was not only fast and convenient but also cost effective and ecofriendly, which has good prospects in control of aquaculture diseases.