Biological treatment to remove dissolved selenium from mine-impacted water is often inhibited by the co-contaminant nitrate. In this work, we enriched microbial consortia capable of removing dissolved selenium in the presence of nitrate from native bacteria at sites influenced by coalmine seepages with elevated concentrations of Se, nitrate, and sulfate. Enrichments were collected from sediments in different vegetated or non-vegetated seepage collection ponds, and all demonstrated the potential for dissolved selenium removal. Nitrate inhibited dissolved selenium removal rates in four of these enrichments. However, microorganisms enriched from a mine seepage influenced natural vegetated marsh removed dissolved Se and nitrate simultaneously. Additionally, enrichments from one seepage collection pond achieved enhanced dissolved selenium removal in the presence of nitrate. Based on functional metagenomics, the dominant species with the metabolic capacity for selenate reduction were classified in Orders Enterobacterales and Clostridiales. Most putative selenate reductases identified as either ygfK, associated with selenoprotein synthesis or production of methylated organoselenium compounds, and narG, nitrate reductases with an affinity also for selenate.

Key points

• Enriched mine influenced sediment bacteria have the capacity for removal of dissolved Se species.

• Consortia from a vegetated natural marsh reduced Se without inhibition from nitrate.

• Nitrate stimulated the removal of Se by consortia from a disused tailing pond.

Graphical abstract

中文翻译：

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在受煤矿影响的环境中富含硝酸盐的情况下，能够减少硒酸盐的微生物群落

从矿井影响水中去除溶解的硒的生物处理通常受到共污染硝酸盐的抑制。在这项工作中，我们丰富了微生物群落，该群落能够在受到矿井渗漏影响的含硒，硝酸盐和硫酸盐浓度升高的地方，从天然细菌中去除硝酸盐存在下的溶解硒。从不同的植被或非植被的渗漏收集池中的沉积物中收集了富集物，所有这些都表明了去除溶解硒的潜力。硝酸盐在其中四个浓缩物中抑制了溶解的硒去除速率。然而，从矿山渗流中富集的微生物影响了天然植被沼泽，同时去除了溶解的硒和硝酸盐。另外，在硝酸盐的存在下，从一个渗漏收集池进行的富集提高了溶解硒的去除率。基于功能性宏基因组学，具有硒酸盐还原代谢能力的优势种按顺序分类肠杆菌和梭菌。大多数推定的硒酸盐还原酶被鉴定为ygfK，与硒蛋白合成或甲基化有机硒化合物的产生有关； narG，硝酸盐还原酶也对硒酸盐具有亲和力。

关键点

•富矿影响的沉积物细菌具有去除溶解的硒物种的能力。

•来自植被自然沼泽的财团减少了硒，却没有硝酸盐的抑制作用。

•硝酸盐刺激了财团从废弃的尾矿池中去除硒。

图形概要