title: Hydrogen threshold concentrations in pure cultures of halorespiring bacteria and at a site polluted with chlorinated ethenes.
abstract: Halorespiring microorganisms are not only able to oxidize organic electron donors such as formate, acetate, pyruvate and lactate, but also H(2). Because these microorganisms have a high affinity for H(2), this may be the most important electron donor for halorespiration in the environment. We have studied the role of H(2)-threshold concentrations in pure halorespiring cultures and compared them with mixed cultures and field data. We have found H(2)-threshold values between 0.05 and 0.08 nM for Sulfurospirillum halorespirans, S. multivorans and Dehalobacter restrictus under PCE-reducing and nitrate-reducing conditions. The reduction of PCE and TCE can proceed at H(2) concentrations of below 1 nM at a polluted site. However, for the reduction of lower chlorinated ethenes a higher H(2) concentration is required. This indicates that the measured H(2) concentration in situ can be an indicator of the extent of anaerobic reductive dechlorination.
authors.affiliation: Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands. m.l.g.c.luijten@mep.tno.nl
authors.forename: Maurice L G C
authors.initials: ML
authors.lastname: Luijten
authors.forename: Wim
authors.initials: W
authors.lastname: Roelofsen
authors.forename: Alette A M
authors.initials: AA
authors.lastname: Langenhoff
authors.forename: Gosse
authors.initials: G
authors.lastname: Schraa
authors.forename: Alfons J M
authors.initials: AJ
authors.lastname: Stams
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019015:Geologic Sediments / Q000382:microbiology*; D006859:Hydrogen / Q000378:metabolism*; D009426:Netherlands; D012989:Soil Pollutants / Q000378:metabolism; D013750:Tetrachloroethylene / Q000378:metabolism; D014241:Trichloroethylene / Q000378:metabolism
chemical_list: D012989:Soil Pollutants; D014241:Trichloroethylene; D006859:Hydrogen; D013750:Tetrachloroethylene