Sericin-mediated green production of silver nanoparticles with potent antibacterial activity against prawn pathogen Vibrio parahaemolyticus

The increasing occurrence of antibiotic-resistant Vibrio species has become a major concern in aquaculture, particularly for the control of Vibrio parahaemolyticus, the causative agent of Acute Hepatopancreatic Necrosis Disease (AHPND), which leads to severe mortality and substantial economic losses in shrimp farming across many Asian countries. Therefore, the development of sustainable and non-antibiotic antibacterial strategies is urgently needed. In this study, silver nanoparticles (AgNPs) were synthesized using silk sericin (SS), an underutilized by-product of the sericulture industry, which served as both a natural reducing and stabilizing agent. Spherical AgNPs with a mean diameter of 12.9 ± 3.4 nm were successfully produced at an AgNO₃-to-SS weight ratio of 1:3 under alkaline conditions. Comprehensive physicochemical characterization confirmed their nanoscale size, high crystallinity, and strong colloidal stability for at least four weeks. Antibacterial assays showed a minimum inhibitory concentration (MIC) of 16 μg·mL⁻¹ and a minimum bactericidal concentration (MBC) of 32 μg·mL^-1 against V. parahaemolyticus, indicating strong antimicrobial activity of the biogenic AgNPs. These results suggest that SS-mediated AgNPs represent a promising non-antibiotic strategy for controlling V. parahaemolyticus infections in aquaculture. In addition, the valorization of SS into functional nanomaterials highlights its potential for broader biomedical and biotechnological applications while supporting the sustainable utilization of sericulture waste. The nanoparticles were produced through a simple, eco-friendly, low-energy one-pot synthesis that is potentially suitable for industrial-scale production.