An environmentally benign method for the biosynthesis of stable selenium nanoparticles

Abstract

An easy, eco-friendly, and low-cost biological method is described for the biosynthesis of selenium nanoparticles by a native Enterobacter sp. strain. The bacterial colony was isolated from a local chrome mine and was capable of reducing selenium (IV) to Se (0) under green and economic in vitro conditions. The synthesized selenium nanoparticles were easily confirmed by changes in the color of medium from yellow to deep red. The prepared rod-shape and crystalline nanoparticles were then characterized by SEM, EDX, XRD, and UV–Vis spectroscopy. According to the obtained results, the prepared selenium nanoparticles (90–120 nm) were predominantly monodispersed and were stable for more than 2 months without significant aggregation. The bacterial proteins are believed to be responsible for the long-term stability of the biogenic Se nanoparticles. The central composite design was used to optimize the synthesis of selenium nanoparticles. Moreover, the present method has no need for the addition of any specific stabilizer and an incubator without shaking is sufficient for the production of the desired Se-NP’s.