Simultaneous selenate reduction and denitrification by a consortium of enriched mine site bacteria.
Simultaneous selenate reduction and denitrification by a consortium of enriched mine site bacteria.
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DOI：
10.1016/j.chemosphere.2017.05.144
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发表时间：
2017-09
期刊：
影响因子：
8.8
通讯作者：
G. Subedi;Jon Taylor;Ido Hatam;S. Baldwin
中科院分区：
文献类型：
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作者：
G. Subedi;Jon Taylor;Ido Hatam;S. Baldwin
由于硒的生物累积倾向和致畸毒性，矿区下游水生环境中硒浓度的增加引起了极大的关注。由于硝酸盐的存在，从受矿影响的水中去除硒变得复杂，由于采矿中使用炸药，硝酸盐在受矿影响的水中也升高。在许多生物处理过程中，硝酸盐作为一种化学上更优选的电子受体抑制了硒酸盐的还原。在这里，我们报告的富集细菌组合从矿山影响的天然沼泽沉积物，能够同时减少硒酸盐和反硝化。硒还原遵循一级动力学相对于总溶解硒的浓度。在3-143 mg L−1-NO3−-N范围内，动力学速率常数与初始硝酸盐浓度无关。硒酸盐的初始浓度在1-24 mg-Se L− 1范围内抑制硒酸盐还原动力学。在仅硒酸盐培养基中生长的优势类群被分类为假单胞菌属（Pseudomonas）、赖氨酸芽孢杆菌属（LysinibacillusandThauera）。当硝酸盐与硒酸盐一起被引入时，以前罕见的类群成为优势类群，这些类群是古细菌、提氏菌和梭菌的亲戚。鉴定了假单胞菌属、索厄氏菌属和梭菌属与异化反硝化作用相关的开放阅读框（ORF）。此外，发现ORF与已知的硒酸还原酶亚基（SerA和SerB）同源。这些研究结果表明，本地矿山现场细菌可以用于去除矿山废水中的硒酸盐和硝酸盐。
Increasing selenium concentrations in aquatic environments downstream of mine sites is of great concern due to selenium's bioaccumulation propensity and teratogenic toxicity. Removal of selenium from mine influenced water is complicated by the presence of nitrate, which is also elevated in mine influenced water due to the use of explosives in mining. In many biological treatment processes, nitrate as a thermodynamically more preferable electron acceptor inhibits selenate reduction. Here we report on an enrichment of a bacterial assemblage from a mine impacted natural marsh sediment that was capable of simultaneous selenate reduction and denitrification. Selenate reduction followed first order kinetics with respect to the concentration of total dissolved selenium. The kinetic rate constant was independent of initial nitrate concentration over the range 3–143 mg L−1-NO3−-N. The initial concentration of selenate inhibited selenate reduction kinetics over the range 1–24 mg-Se L−1.Dominant taxa that grew in selenate only medium were classified in the generaPseudomonas, LysinibacillusandThauera. When nitrate was introduced in addition to selenate, previously rare taxa that became dominant were relatives ofExiguobacterium, TissierellaandClostridium. Open reading frames (ORFs) associated with dissimilatory denitrification were identified forPseudomonas,ThaueraandClostridium. In addition, ORFs were found that were homologous with known selenate reductase subunits (SerA and SerB). These findings suggest that native mine site bacteria can be used for removing selenate and nitrate from mine wastewater.