Open AccessTransformation of monothioarsenate by haloalkaliphilic, anoxygenic photosynthetic purple sulfur bacteria
Author(s) -
Edwardson Christian F.,
PlanerFriedrich Britta,
Hollibaugh James T.
Publication year - 2014
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/1574-6941.12440
Subject(s) - anoxygenic photosynthesis , biology , arsenate , anoxic waters , arsenite , arsenic , sulfur , photosynthesis , environmental chemistry , botany , green sulfur bacteria , bacteria , purple bacteria , phototroph , ecology , chemistry , genetics , organic chemistry , photosynthetic reaction centre
Thioarsenates are the dominant arsenic species in arsenic‐rich, alkaline, and sulfidic waters, but bacterial interactions with these compounds have only recently been examined. Previous studies have shown that microorganisms play a role in the transformation of monothioarsenate to arsenate, including use of monothioarsenate as a chemolithotrophic electron donor coupled with oxygen as an electron acceptor. We obtained enrichment cultures from two saline, alkaline lakes (Mono Lake, CA and Big Soda Lake, NV) that are able to use monothioarsenate as the sole electron donor for anoxygenic photosynthesis. These anoxic cultures were able to convert a 1 mM mixture of thioarsenates completely to arsenate in c . 13 days and 4 mM monothioarsenate to arsenate in c . 17 days. This conversion was light dependent; thus, monothioarsenate can be used as the sole electron donor for anoxygenic photosynthesis. Both of the Mono Lake and Big Soda Lake enrichment cultures were dominated by an organism closely related to Ectothiorhodospira species. We tested additional strains of purple sulfur bacteria and found widespread ability to use monothioarsenate as an electron donor. The ability of bacteria to transform thioarsenates directly via anoxygenic photosynthesis adds a new perspective to the well‐studied arsenic and sulfur cycles.