OICC Press Journal of Nanostructure in Chemistry 2193-8865 3 1 (December 2013) 2013 05 08 Eco-friendly synthesis and characterization of gold nanoparticles using Klebsiella pneumoniae 10.1186/2193-8865-3-30 EN Chelladurai Malarkodi Environmental Nanotechnology Division, Sri Paramakalyani Centre for Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tamil Nadu, 627 412, IN Shanmugam Rajeshkumar Environmental Nanotechnology Division, Sri Paramakalyani Centre for Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tamil Nadu, 627 412, IN Mahendran Vanaja Environmental Nanotechnology Division, Sri Paramakalyani Centre for Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tamil Nadu, 627 412, IN Kanniah Paulkumar Environmental Nanotechnology Division, Sri Paramakalyani Centre for Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tamil Nadu, 627 412, IN Gnanadhas Gnanajobitha Environmental Nanotechnology Division, Sri Paramakalyani Centre for Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tamil Nadu, 627 412, IN Gurusamy Annadurai Environmental Nanotechnology Division, Sri Paramakalyani Centre for Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tamil Nadu, 627 412, IN Journal Article 2013 05 08 Abstract The thrust to develop eco-friendly procedures for the production of nanoparticles arises from the extremely recent nanotechnology research. Extracellular biosynthesis of gold nanoparticles was achieved by an easy biological procedure using Klebsiella pneumoniae as the reducing agent. After exposing the gold ions to K. pneumoniae , rapid reduction of gold ions is observed foremost to the formation of gold nanoparticles in colloidal solution. UV-vis spectrum of the aqueous medium containing gold nanoparticles showed a peak around 560 nm. The crystalline nature of the particles was confirmed from an X-ray diffractometer. Transmission electron microscopy (TEM) micrograph analysis of the gold nanoparticles indicated that they were well dispersed and ranged in sizes 35 to 65 nm. The high crystalline in the FCC phase is evidenced by bright circular spots in a selected-area electron diffraction pattern and clear lattice fringes in the high-resolution TEM image. Fourier transform infrared spectroscopy revealed possible involvement of reductive groups on the surface of nanoparticles. The method exploits a cheap and easily available biomaterial not explored so far for the synthesis of metallic nanoparticles.