Bacillus cereus, selenite-reducing bacterium from contaminated lake of an industrial area: a renewable nanofactory for the synthesis of selenium nanoparticles

Abstract

Background: An attempt was made to isolate selenite-reducing bacteria from a contaminated lake that receives industrial effluents and domestic sewage. The isolated dominant bacterial strain AJK3 was identified as Bacillus cereus, based on biochemical characterization and 16S rDNA sequencing. The time dependent selenium removal at different selenite concentrations monitored with ICP-AES indicates the substantial selenite reduction capability of the isolated strain. The selenium nanoparticles produced during the bacterial reduction of selenite were analyzed with UV–visible spectroscopy, X-ray diffraction, transmission electron microscopy, zeta potential measurement, Fourier transform infrared spectroscopy and Raman spectroscopy. Results: The nanoparticle synthesis was confirmed from the red colour emergence in culture broth and wide UV–vis peaks. The produced nanoparticles were polydisperse, spherical, size varied from 50 to 150 nm and the mean particle size was about 93 nm. The amorphous nature of the generated nanoparticles was confirmed from the Raman spectroscopy, XRD and SAED patterns. The IR data and zeta potential values substantiated the protein capping of the produced nanoparticles. Conclusions: Thus, the present study suggests that the isolated bacterial strain can be exploited as a prospective, renewable, natural, nanofactory for the bacteriogenic synthesis of nanoparticles. Also, the study has application in bioremediation of selenite from the contaminated environment. [Figure not available: see fulltext.].