Abstract

Cell-associated biosynthesis of cadmium sulfide (CdS) nanoparticles has been reported to be rather slow and costly. In this study, we report on a rapid and low cost biosynthesis of CdS using culture supernatants of Escherichia coli ATCC 8739,Bacillus subtilis ATCC 6633 and Lactobacillus acidophilus DSMZ 20079T. The synthesis was performed at room temperature in the laboratory ambience and CdS nanoparticles were formed within 24 h. Ultraviolet (UV)–visible spectroscopy study revealed the build-up of absorption bands at 419.5, 381.5 and 362.5 nm for E. coliATCC 8739, B. subtilis ATCC 6633 and L. acidophilus DSMZ 20079T, respectively for assisted synthesis of CdS nanoparticles. X-ray diffraction (XRD), transmission electron microscopy (TEM) and fluorescence spectral analyses were performed to ascertain the formation of CdS nanoparticles. Individual nanoparticles as well as few aggregates having the size of 2.5 to 5.5 nm were found. The process of extracellular and fast biosynthesis may help in the development of an easy and eco-friendly route for the synthesis of CdS nanoparticles.

Key words: Nano-cadmium sulfide (CdS), nanomaterials, nanobiotechnology, biosynthesis, Escherichia coli, Bacillus subtilis, Lactobacillus acidophilus.