Extracellular biosynthesis of Selenium nanoparticles using some species of Lactobacillus

Selenium (Se), a non-metallic chemical element exhibits many properties like relatively high thermoconductivity, superconductivity, catalytic activities. In addition, Se is one of the key elements for maintaining the health of mammalian animals because of its anti-oxidative and pro-oxidative effects. In the present study, we describe the biosynthesis of highly stable selenium nanoparticles using three species of non-pathogenic, ecofriendly and easily available Lactic acid bacteria (LAB): Lactobacillus acidophilus, Lactobacillus plantarum and Lactobacillus rhamnosus was reported. Lactic acid bacteria can reduce selenium ions to elemental selenium nanoparticles (SeNPs) and deposit them in intracellular spaces. Reduction of Se+ ions in metal nanoparticles was investigated virtually by tracing the solution color which changed red after 48 hrs. Biosynthesized selenium nanoparticles were spherical (by TEM) in shape with size range of 20nm to 150 nm (UV spectrum). Moreover, as inferred from the FUR. spectrum, the presences of highly stable carbonyl group from the aminoacids have the strong ability to bind with the metal. Nanoparticles were further analysed for antimicrobial activity against pathogenic fungi, and they exhibited significant microbial activity.