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Anaerobic oxidation of arsenite in Mono Lake water and by a facultative, arsenite-oxidizing chemoautotroph, strain MLHE-1

Applied and Environmental Microbiology

By:
, , , , ,
DOI: 10.1128/AEM.68.10.4795-4802.2002

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Abstract

Arsenite [As(III)]-enriched anoxic bottom water from Mono Lake, California, produced arsenate [As(V)] during incubation with either nitrate or nitrite. No such oxidation occurred in killed controls or in live samples incubated without added nitrate or nitrite. A small amount of biological As(III) oxidation was observed in samples amended with Fe(III) chelated with nitrolotriacetic acid, although some chemical oxidation was also evident in killed controls. A pure culture, strain MLHE-1, that was capable of growth with As(III) as its electron donor and nitrate as its electron acceptor was isolated in a defined mineral salts medium. Cells were also able to grow in nitrate-mineral salts medium by using H2 or sulfide as their electron donor in lieu of As(III). Arsenite-grown cells demonstrated dark 14CO2 fixation, and PCR was used to indicate the presence of a gene encoding ribulose-1,5-biphosphate carboxylase/oxygenase. Strain MLHE-1 is a facultative chemoautotroph, able to grow with these inorganic electron donors and nitrate as its electron acceptor, but heterotrophic growth on acetate was also observed under both aerobic and anaerobic (nitrate) conditions. Phylogenetic analysis of its 16S ribosomal DNA sequence placed strain MLHE-1 within the haloalkaliphilic Ectothiorhodospira of the ??-Proteobacteria. Arsenite oxidation has never been reported for any members of this subgroup of the Proteobacteria.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Anaerobic oxidation of arsenite in Mono Lake water and by a facultative, arsenite-oxidizing chemoautotroph, strain MLHE-1
Series title:
Applied and Environmental Microbiology
DOI:
10.1128/AEM.68.10.4795-4802.2002
Volume
68
Issue:
10
Year Published:
2002
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
4795
Last page:
4802
Number of Pages:
8