Chemolithotrophic growth of the aerobic hyperthermophilic bacterium Thermocrinis ruber OC 14/7/2 on monothioarsenate and arsenite

authored by

Cornelia Haertig, Regina Lohmayer, Steffen Kolb, Marcus A. Horn, William P. Inskeep, Britta Planer-Friedrich

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.

Organisation(s)

Institute of Microbiology

Type

Article

Journal

FEMS microbiology ecology

Volume

Pages

747-760

No. of pages

ISSN

0168-6496

Publication date

01.12.2014

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Microbiology, Ecology, Applied Microbiology and Biotechnology

Electronic version(s)

https://doi.org/10.1111/1574-6941.12431 (Access: Open)