Bioreduction and Formation of Selenium Containing Nanocrystallites by Selenium Tolerant Aerobic Bacterium SNT1

The common oxidation states of selenium found in the environment are selenides (-2), selenium (0), selenites (+4), and selenates (+6). The reduction of selenium oxyanions viz., selenate and selenite to insoluble Se which is less toxic form of selenium, has been reported in numerous bacteria and in some cases thought to be a detoxification mechanism [1]. Selenium reduction mechanisms in anaerobic bacteria have been attributed to pathways leading to dissimilatory metal reduction [2]. However, selenium reduction as a detoxification mechanism in aerobic bacteria has been observed only in few genera.