Green Synthesis of Silver Nanoparticles Using Dextran from Weissella Confusa

Dextran a polymer of glucose is produced by different microorganisms like Leuconostoc mesenteroides, Lactobacillus sps, Streptococcus mutants, Weissella confusa etc. It has a wide range of applications in the food, pharmaceuticals and other industries. It also has significant role in green synthesis of silver nanoparticles. In the present study an efficient low molecular dextran produced by an indigenous isolate Weissella confusa isolated from idli batter was used. The dextran produced was a low molecular weight one as indicated by HPLC analysis. Both the sample dextran and commercial dextran silver nanoparticles were prepared by simple one step method. In this method dextran acted as both reducing and stabilizing agent that reduced silver nitrate (AgNO3) and also acted as protecting agent for nanoparticles. The formation of nanoparticles is assured by characterization with UV-vis spectroscopy, scanning electron microscopy (SEM). The absorbance of silver nanoparticles is observed at 430nm. Scanning electron microscopy images shows that the nanoparticles are spherical in shape with 48-53nm dimensions. The antimicrobial activity of these synthesized silver nanoparticles was tested against bacteria like Staphylococcus aureus and Escherichia coli. The results confirmed that the tested bacteria were inhibited as indicated by higher zones of inhibition. These non-toxic nanomaterials which can be prepared in a simple and costeffective manner by green synthesis may be suitable for the formulation of new types of bactericidal agents.