Rapid Biosynthesis of Silver Nanoparticles Based on Flocculation and Reduction of an Exopolysaccharide from Arthrobacter sp. B4: Its Antimicrobial Activity and Phytotoxicity

Silver nanoparticles (AgNPs) were rapidly synthesized using an exopolysaccharide from Arthrobacter sp. B4 (B4-EPS). The optimum condition for AgNPs synthesis was under the concentration of 5 g/L B4-EPS and 1 mM AgNO3 at 80°C between pH 7.0 and 8.0. The resulting AgNPs displayed a face-centred-cubic structure with the size range from 9 nm to 72 nm. Further analysis showed that flocculation and reduction of B4-EPS played a pivotal role in the formation of AgNPs. Furthermore, these nanoparticles exhibited great stability, excellent antimicrobial activity, and low phytotoxicity. The aforementioned data provide a feasible and efficient approach for green synthesis of AgNPs using microbial polysaccharides with flocculation and reduction activity, which will be promising in medical filed