Reduction of selenium oxyanions by Enterobacter cloacae strain SLD1a‐1: Reduction of selenate to selenite
Reduction of selenium oxyanions by Enterobacter cloacae strain SLD1a‐1: Reduction of selenate to selenite
复制标题
阴沟肠杆菌菌株 SLD1a-1 还原硒氧阴离子：将硒酸盐还原为亚硒酸盐
DOI：
10.1002/etc.5620160913
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发表时间：
1997
影响因子：
4.1
通讯作者：
W. Frankenberger
中科院分区：
文献类型：
--
作者：
M. Losi;W. Frankenberger
研究了从农业排水中分离的兼性厌氧菌阴沟肠杆菌菌株SLD1a‐1 （ATCC 700258）对硒酸盐（SeO2−4）还原为亚硒酸盐（SeO2−3）的微观实验。以葡萄糖为电子供体，洗涤后的细胞悬浮液在10.5 h内去除了92%的添加的SeO2−4 （127 μM）。开发了一种方法，可以评估仅影响将SeO2−4还原为SeO2−3的因素，这是将SeO2−4还原为Se0和/或Se2−的第一步。该方法包括用2,4 -二硝基苯酚（DNP）处理细胞悬浮液，之后SeO2 - 4的还原过程相对无阻，但SeO2 - 3的还原受到抑制，并且SeO2 - 3在溶液中积累并被量化。最适pH为6.5 ~ 7.0，电导率大于等于10 dS m−1，抑制了该反应。NO3−、NO2−、SO2−4、AsO3−4和Fe3+等摩尔浓度对SLD1a‐1还原127 μM的SeO2−4没有影响，但NO3−和SO2−4浓度分别为SeO2−4的5倍和236倍，CrO2−4和SO2−3浓度与SeO2−4等摩尔浓度对SLD1a‐1还原有抑制作用。研究发现，电子给体越容易进入糖酵解途径，其促进SeO2−4还原的倾向越大。此外，最初在乳糖和麦芽糖的存在下生长的生物体增强了生物体随后使用这些电子供体来还原SeO2−4的能力。反应的最佳温度为30℃，降低氧浓度可促进溶液中SeO2−4的还原和硒的去除。我们的研究结果为利用阴沟肠杆菌SLD1a‐1处理硒污染水的生物反应器的优化提供了有用的信息。
Reduction of selenate ( SeO2−4) to selenite ( SeO2−3) by Enterobacter cloacae strain SLD1a‐1 (ATCC 700258), a facultative anaerobe isolated from agricultural drainage water, was studied in microcosm experiments using washed cell suspensions. The washed cell suspension removed 92% of added SeO2−4 (at 127 μM) from solution over 10.5 h using glucose as the electron donor. A method was developed that allowed for the assessment of factors affecting only reduction of SeO2−4 to SeO2−3, the first step in the reduction of SeO2−4 to Se0 and/or Se2−. The method consisted of treating the cell suspensions with 2,4‐dinitrophenol (DNP), after which SeO2−4 reduction proceeds relatively unimpeded but SeO2−3 reduction is inhibited and SeO2−3 accumulates in solution and is quantified. Optimum pH was found to be 6.5–7.0, and an electrical conductivity of 10 dS m−1 and greater inhibited the reaction. Reduction of SeO2−4 at 127 μM by SLD1a‐1 was unaffected by NO3−, NO2−, SO2−4, AsO3−4, and Fe3+ at equimolar concentrations but was inhibited by NO3− and SO2−4 at levels 5 and 236 times greater, respectively, than the SeO2−4 concentration and by CrO2−4 and SO2−3 at concentrations equimolar with that of SeO2−4. It was found that the more easily an electron donor enters the glycolytic pathway, the greater its propensity to promote SeO2−4 reduction. In addition, initially growing the organism in the presence of lactose and maltose enhanced the organism's subsequent use of these electron donors in reduction of SeO2−4. Optimum temperature for the reaction was 30°C, and lowering the oxygen level enhanced SeO2−4 reduction and removal of Se from solution. Our results provide useful information for optimization of a bioreactor using E. cloacae SLD1a‐1 to treat Se‐contaminated water.