Production and structural characterization of crystalline silver nanoparticles from Bacillus cereus isolate.

To date, biosynthesis of metal nanoparticles has been intensively studied using bacteria and fungi. We have isolated and identified metal resistant bacterial strains from electroplating industries, they produce silver nanoparticles. The reduction reaction of aqueous silver nitrate with bacterial biomass was carried out for 120 h. Bacteria produced metallic nanoparticles showed a strong absorbance at surface plasmon resonance wavelength around 420 nm. The size and morphology of these nanoparticles were typically imaged using high resolution transmission electron microscopy, the particles size ranges between 4 and 5 nm and are spherical in shape. The crystal structure of the particles was characterized by X-ray diffraction pattern. The full width half maxima from X-ray diffraction measurements indicated that the particles exhibited face-centered cubic phase.