Abstract: The aim of the study was to explore the biogenesis of nano-structures through reduction of selenium by soil bacterium Pseudomonas aeruginosa. The strain under study indicated tolerance of selenium upto 50 mg L-1, using reductive mechanisms for detoxication, thus biotransforming selenium oxyanions to elemental red selenium. Partial characterization using AFM of the biotransformed selenium was carried out which indicated formation of spherical amorphous allotropic elemental selenium.