Thioarsenate Transformation by Filamentous Microbial Mats Thriving in an Alkaline, Sulfidic Hot Spring
Thioarsenate Transformation by Filamentous Microbial Mats Thriving in an Alkaline, Sulfidic Hot Spring
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DOI：
10.1021/es204277j
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发表时间：
2012-04-17
影响因子：
11.4
通讯作者：
Planer-Friedrich, Britta
中科院分区：
文献类型：
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作者：
Haertig, Cornelia;Planer-Friedrich, Britta
硫代砷酸盐在硫化地热沃茨中占主导地位，但对它们在环境中的命运知之甚少。在黄石国家公园的碱性温泉海螺泉，三硫代砷酸盐在沿着排水道氧化性增加的条件下转化为砷酸盐，伴随着一硫代砷酸盐和亚砷酸盐的初始增加，然后减少。现场培养试验进行了使用无菌过滤的水与和不添加丝状微生物垫从排水通道区分砷物种转化的非生物和生物过程的作用。在非生物条件下，三硫代砷酸盐被还原为砷酸盐，并与硫化物氧化反应相结合。然而，一硫代砷酸盐是惰性的。生物培养证明，亚砷酸盐在排水通道中的中间积累是微生物催化的。在硫化物的存在下，微生物增强的硫化物氧化加上还原的砷酸亚砷酸盐，可以简单地提高非生物的三硫代砷酸盐和潜在的monothioarsenate的反硝化作用。然而，我们也能够显示，在无硫化物培养基中，直接微生物转化的单硫代砷酸盐的砷酸盐。中间形成了一些亚砷酸盐，随后也被微生物氧化为砷酸盐。这项研究是微生物介导的硫代砷酸盐物种转化（超）嗜热原核生物的第一个证据。
Thioarsenates dominate arsenic speciation in sulfidic geothermal waters, yet little is known about their fate in the environment. At Conch Spring, an alkaline hot spring in Yellowstone National Park, trithioarsenate transforms to arsenate under increasingly oxidizing conditions along the drainage channel, accompanied by an initial increase, then decrease of monothioarsenate and arsenite. On-site incubation tests were conducted using sterile-filtered water with and without addition of filamentous microbial mats from the drainage channel to distinguish the role of abiotic and biotic processes for arsenic species transformation. Abiotically, trithioarsenate was desulfidized to arsenate coupled to sulfide oxidation. Monothioarsenate, however, was inert. Biotic incubations proved that the intermediate accumulation of arsenite in the drainage channel is microbially catalyzed. In the presence of sulfide, microbially enhanced sulfide oxidation coupled to reduction of arsenate to arsenite could simply enhance abiotic desulfidation of trithioarsenate and potentially also monothioarsenate. However, we were also able to show, in sulfide-free medium, direct microbial transformation of monothioarsenate to arsenate. Some arsenite formed intermediately, which was subsequently also microbially oxidized to arsenate. This study is the first evidence for microbially mediated thioarsenate species transformation by (hyper)thermophilic prokaryotes.