Abstract: The aim of this study was to optimize the green synthesis process of emblicpolysaccharide-silver nanoparticles.The Ag⁺ of AgNO₃ was reduced to the silver level of nano-grade using emblic polysaccharide as reducing agent and stabilizer.On the basis of single factors,the inhibitory rate of AgNPs against Staphylococcus aureuswas the response value,the effects of AgNO₃ and polysaccharide volume ratio,NaCl volume and UV irradiation time on the preparation of AgNPs was studied.According to the principle of Box-Benhnken center combination test,three factors and three levels were used to determine the optimal process.The results showed:the AgNPs particles had significant bacteriostatic effect on S.aureus.The optimal preparation conditions of AgNPs were as follows: the ratio of AgNO₃ to polysaccharide was 2:1 (mL/mL),the volume of NaCl was 1.5 mL,and the UV irradiation time was 1 h.Under these conditions,the diameter of the inhibition zone was 2.79 ± 0.01 cm.

Key words: Phyllanthus emblica crude polysaccharide, silver nanoparticles, response surface methodology, antibacterial