The Determination of Biomass / Selenium Ratio and the Impact of Glucose and Piperitone upon Selenium Ion Reduction Using Bacillus sp. MSh-1 Whole Cells

Many bacteria are potential to reduce the metal ions to elemental nanoparticles and are able to grow in the presence of these inorganic compounds. Whole bacterial cells suspended in aqueous media can also convert some soluble metal ions into elemental nanomaterials. In this study, the reduction of different concentrations of selenium ions was investigated using various amounts of Bacillus sp. MSh-1 whole cell biomass, with the aim of increasing the yield of selenium nanoparticles. The MSh-1 test strain used in this study was previously isolated from the Caspian Sea (north of Iran) which can produce selenium nanoparticles. Reduction of selenium ions by whole Bacillus sp. MSh-1 cells in normal saline had a close relation between the ratio of applied biomass and the selenium ion concentration, as no considerable reduction was detected in the ratios lower than 1 gram of biomass for each 100 mg of selenium. Neither compounds of piperitone nor glucose had positive effects on selenium reduction by Bacillus sp. MSh-1. It also should be mentioned that Se NPs were not efficiently produced even after 20 hours and 32 hours, respectively.