title: Chemolithotrophic growth of the aerobic hyperthermophilic bacterium Thermocrinis ruber OC 14/7/2 on monothioarsenate and arsenite.
abstract: Novel insights are provided regarding aerobic chemolithotrophic growth of Thermocrinis ruber OC14/7/2 on the electron donors arsenite and monothioarsenate. Thermocrinis ruber is a hyperthermophilic bacterium that thrives in pH-neutral to alkaline hot springs and grows on hydrogen, elemental sulfur, and thiosulfate. Our study showed that T. ruber can also utilize arsenite as sole electron donor producing arsenate. Growth rates of 0.024 h(-1) were lower than for oxidation of thiosulfate to sulfate (μ = 0.247 h(-1)). Fast growth was observed on monothioarsenate (μ = 0.359 h(-1)), comprising different abiotic and biotic redox interactions. The initial dominant process was abiotic transformation of monothioarsenate to arsenate and elemental sulfur, followed by microbial oxidation of sulfur to sulfate. Elevated microbial activity during stationary growth of T. ruber might be explained by microbial oxidation of thiosulfate and arsenite, both also products of abiotic monothioarsenate transformation. However, the observed rapid decrease of monothioarsenate, exceeding concentrations in equilibrium with its products, also indicates direct microbial oxidation of arsenic-bond S(-II) to sulfate. Free sulfide was oxidized abiotically too fast to play a role as electron donor for T. ruber. Our present laboratory and previous field studies suggest that thioarsenates can either indirectly or directly be used by (hyper)thermophiles in arsenic-sulfidic environments.
authors.affiliation: Department of Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Härtig
authors.forename: Regina
authors.initials: R
authors.lastname: Lohmayer
authors.forename: Steffen
authors.initials: S
authors.lastname: Kolb
authors.forename: Marcus A
authors.initials: MA
authors.lastname: Horn
authors.forename: William P
authors.initials: WP
authors.lastname: Inskeep
authors.forename: Britta
authors.initials: B
authors.lastname: Planer-Friedrich
mesh_terms: D001149:Arsenates / Q000378:metabolism*; D001151:Arsenic / Q000378:metabolism; D018053:Arsenites / Q000378:metabolism*; D001419:Bacteria / Q000254:growth & development / Q000378:metabolism*; D052837:Chemoautotrophic Growth; D045482:Hot Springs / Q000382:microbiology; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D013431:Sulfates / Q000378:metabolism*; D013440:Sulfides / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism
chemical_list: D001149:Arsenates; D018053:Arsenites; D013431:Sulfates; D013440:Sulfides; D013455:Sulfur; C015001:arsenite; D001151:Arsenic; C025657:arsenic acid
keywords: Aquificales; Yellowstone National Park; biogeochemistry; chemolithotrophy; thioarsenic species