Authors: William J Hunter
Publish Date: 2007/05/04
Volume: 54, Issue: 5, Pages: 376-381
Abstract
A bacterium that reduces the soluble selenium oxyanions selenate and selenite to insoluble elemental red selenium Se0 was isolated from a laboratory reactor developed to remove selenate from groundwater Gene sequence alignment of the 16S rRNA allowed identification of the isolate as Azospira oryzae Biochemical and morphologic characterization confirm the identification The isolate reduces selenate and selenite to Se0 under microaerophilic and denitrifying conditions but not under aerobic conditions It does not use selenate or selenite as terminal e¯ donors Se oxyanion reduction causes the formation of Se nanospheres that are 025 ± 004 μm in diameter Nanospheres may be associated with the cells or free in the medium The enzymatic activity associated with the reduction of selenate has a molecular mass of approximately 500 kD and the enzymatic activity associated with the reduction of selenite has a mass of approximately 55 kD Selenite reduction was inhibited by tungsten The molecular masses of these activities were different from those associated with the reduction of dimethylsulfoxide sulfate and nitrite This bacterium or perhaps its enzymes or DNA might be useful for the remediation of waters contaminated with Se oxyanionsThe author thanks Robin Montenieri and Cathy Cannon for expert technical assistance Manufacturer and product names are given for readers’ convenience and do not reflect endorsement by the United States government This article was the work of United States government employees engaged in their official duties and is exempt from copyright
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