Green synthesis and physical properties of Gum Arabic‐silver nanoparticles and its antibacterial efficacy against fish bacterial pathogens

This study aimed to assess the antibacterial efficacy of Gum Arabic-based silver nanoparticles against certain fish bacterial pathogens. Silver nanoparticles were green-synthesized using Gum Arabic (AgNPs-GA), which served as a stabilizing and reducing agent. The AgNPs-GA were analysed using a UV spectrophotometer set at a wavelength of 450 nm. Transmission electron micrograph analysis showed that nearly all AgNPs-GA were sphere-shaped and 10.0 nm in diameter. Dynamic light scattering (DLS) analysis showed a narrow size distribution curve, whose highest peak was at 26.2 nm. The particles were negatively charged (−17.1 ± 4.9 mV). Silver concentration measured by inductively coupled plasma optical emission spectrometry (ICP-OES) and found to be 104 µg/ml. The in vitro antibacterial activity of AgNPs-GA was tested against Aeromonas hydrophila and Pseudomonas aeruginosa. Gum Arabic-silver nanoparticles exhibited clear inhibition zones of 22 and 20 mm against A. hydrophila and P. aeruginosa, with a minimum inhibitory concentration of 1.625 µg/ml and 3.25 µg/ml for AgNPs-GA respectively. The antibiofilm activity indicated that AgNPs-GA significantly inhibit A. hydrophila and P. aeruginosa biofilm formation at AgNPs-GA concentrations of 1.625 µg/ml. There was no significant difference at a AgNPs-GA concentration of 0.8215 µg/ml between the control-positive groups and the AgNPs-GA treatment groups in both bacterial strains. In summary, green-synthesized sliver nanoparticles display efficient antibacterial properties, which suggests that they would be suitable for use in a commercialized antibacterial product for the aquaculture industry.