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Title: An autotrophic H 2 -oxidizing, nitrate-respiring, Tc(VII)-reducing A cidovorax sp. isolated from a subsurface oxic-anoxic transition zone: H 2 -oxidizing, Tc-reducing Acidovorax spp.

Increasing concentrations of H2 with depth were observed across a geologic unconformity and associated redox transition zone in the subsurface at the Hanford Site in south-central Washington, USA. An opposing gradient characterized by decreasing O2 and nitrate concentrations was consistent with microbial-catalyzed biogeochemical processes. Sterile sand was incubated in situ within a multi-level sampler placed across the redox transition zone to evaluate the potential for Tc(VII) reduction and for enrichment of H2-oxidizing denitrifiers capable of reducing Tc(VII). H2-driven TcO4- reduction was detected in sand incubated at all depths but was strongest in material from a depth of 17.1 m. Acidovorax spp. were isolated from H2-nitrate enrichments from colonized sand from 15.1 m, with one representative, strain JHL-9, subsequently characterized. JHL-9 grew on acetate with either O2 or nitrate as electron acceptor (data not shown) and on medium with bicarbonate, H2 and nitrate. JHL-9 also reduced pertechnetate (TcO4-) under denitrifying conditions with H2 as the electron donor. H2-oxidizing Acidovorax spp. in the subsurface at Hanford and other locations may contribute to the maintenance of subsurface redox gradients and offer the potential for Tc(VII) reduction.
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1758-2229; 47712; KP1702030
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Microbiology Reports; Journal Volume: 7; Journal Issue: 3
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY Acidovorax; autotrophy; denitrification; H2; iron oxidation; technetium; subsurface; Environmental Molecular Sciences Laboratory