| Abstract
| - Microbial reduction of selenate [Se(VI)] to elemental selenium [Se(0)] is a useful technique for removingSe from agricultural drainage water. A series of batch experiments were conducted in the laboratoryto determine the effects of yeast extract (50−1000 mg/L), salinity (EC, 5−75 dS/m), and NO3- (5−100 mg/L) on the removal of Se(VI) (2000 μg/L) from drainage water by Enterobacter taylorae. Resultsshowed that relatively high amounts of yeast extract (500 mg/L) were needed for E. taylorae toeffectively reduce Se(VI) to Se(0). During a 7-day experiment, ∼95% of added Se(VI) was reducedto Se(0) in the low-salinity drainage water (5 dS/m) with NO3- values of 5−50 mg/L. In the high-salinity drainage water (50−75 dS/m), reduction of Se(VI) to Se(0) was limited. E. taylorae was alsocapable of reducing Se(VI) to Se(0) in the San Joaquin Valley drainage water, with a reduction of theadded Se(VI) to Se(0) (73.8%) and Se(-II) (20%). This study suggests that E. taylorae may be usedto treat Se(VI)-contaminated drainage water in the field. Keywords: Selenium speciation; selenate reduction; nitrate; salinity; yeast extract; Enterobactertaylorae
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