An alternative method for biological production of silver and gold nanoparticles

Abstract

Major purpose of this study was to explore an alternative and simple method for silver and gold nanoparticles
bio-production by Escherichia coli. In the previous (routine) technique for nanoparticles bio-production, after
culturing the bacteria, the bacterial culture supernatant was treated with aqueous solutions of silver nitrate and
chloroauric acid ions. To perform bio-synthesis of silver and gold nanoparticles by the alternative method,
unlike the routine one, the bacteria were subjected to the toxic metal ions immediate after inoculation to the
medium. Bio-production of nanoparticles by these two methods was monitored through visible
spectrophotometry, transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD). The results
showed that silver and gold nanoparticles were produced by both types of the routine and alternative
techniques but the rate of bio-production was relatively more by the alternative one. Moreover, this type of bioproduction is simpler, faster and cleaner than the previous one.