AUTHOR=Wu Geng , Huang Liuqin , Jiang Hongchen , Peng Yue’e , Guo Wei , Chen Ziyu , She Weiyu , Guo Qinghai , Dong Hailiang 

TITLE=Thioarsenate Formation Coupled with Anaerobic Arsenite Oxidation by a Sulfate-Reducing Bacterium Isolated from a Hot Spring

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.01336

DOI=10.3389/fmicb.2017.01336

ISSN=1664-302X

ABSTRACT=<p>Thioarsenates are common arsenic species in sulfidic geothermal waters, yet little is known about their biogeochemical traits. In the present study, a novel sulfate-reducing bacterial strain <italic>Desulfotomaculum</italic> TC-1 was isolated from a sulfidic hot spring in Tengchong geothermal area, Yunnan Province, China. The <italic>arxA</italic> gene, encoding anaerobic arsenite oxidase, was successfully amplified from the genome of strain TC-1, indicating it has a potential ability to oxidize arsenite under anaerobic condition. In anaerobic arsenite oxidation experiments inoculated with strain TC-1, a small amount of arsenate was detected in the beginning but became undetectable over longer time. Thioarsenates (AsO<sub>4-x</sub>S<sub>x</sub><sup>2-</sup> with <italic>x</italic> = 1–4) formed with mono-, di- and tri-thioarsenates being dominant forms. Tetrathioarsenate was only detectable at the end of the experiment. These results suggest that thermophilic microbes might be involved in the formation of thioarsenates and provide a possible explanation for the widespread distribution of thioarsenates in terrestrial geothermal environments.</p>