Biotransformation of Selenite to Red Elemental Selenium

Abstract

Selenium is an element of great interest due to its nutritional importance for humans and animals. Selenium undergoes biotic transformation like oxidation, dissimulator and assimilatory reduction, alkylation and de-alkylation, also due to which “cocktail” of various selenium specie is present in environment, posing a big challenge to Se specie analysis. In current study, we isolated bacterial strain, Bacillus licheniformis, Exiguobacterium sp., Bacillus subtilis, that convert (SeO 3 ) -2 (toxic) to elemental (reduced and less toxic) selenium. Different physical parameters were checked experimentally to increase Se reduction like pH, temperature, selenite concentration, incubation time, aeration. Se reduction increased with increased pH, Maximum reduction, 31 to 90% was check at pH 9 and different strain have different ranges of temperature, optimum temperature 37 °C and 44 °C was noted for selenium reduction. Microbes can reduce selenium in aerobic as well as anaerobic condition and reduction decrease with the increase in incubation time.