Biological Synthesis and Characterization of Silver Nanoparticles using Bacillus thuringiensis A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Master of Science In Life Science By Lilyprava Dash 411LS2044

The present work investigates the synthesis of silver nanoparticles (Ag NPs) by biological method using Bacillus thuringiensis. The MIC test was performed to test the inhibitory concentration of AgNO3 against B. thuringiensis and B. subtilis. Silver nanoparticles were successfully synthesized from B. thuringiensis by green synthesis method. The detailed characterization of the Ag NPs was carried out using UV-visible spectroscopy, Scanning Electron Microscopy (SEM), X Ray Diffraction (XRD), and FTIR. From the UV-visible spectroscopy, the absorption peak was found at 420 nm. From the SEM images, it is confirmed that the sample contains spherical silver nanoparticles. From XRD analysis, it was confirmed that the silver nanoparticles are crystalline in nature, which was confirmed by the FT-IR peak at 518 cm -1 corresponding to the Ag vibration present in crystalline structure. Finally, the antibacterial activity of silver nanoaprticles was determined by spread plate method, and found that silver nanoparticles have significant antibacterial activity against S. aureus and B. subtilis than E. coli.