TABLE 1.

Extent of Fe(II) oxidation and ratio of Fe(II) oxidized to nitrate reduced by the enrichment culture and heterotrophic nitrate-reducing isolates

Culture (class and genus) or culture combination% Fe(II) oxidizedFe(II) oxidized/nitrate reduceda
Enrichment culture965.23 ± 0.14
OTU2 (Betaproteobacteria, Comamonas sp.)165.10 ± 0.21
OTU3 (Alphaproteobacteria, Parvibaculum sp.)184.85 ± 0.11
OTU4 (Gammaproteobacteria, Rhodanobacter sp.)125.31 ± 0.15
OTU2 + OTU3215.03 ± 0.16
OTU3 + OTU4194.93 ± 0.18
OTU2 + OTU4234.81 ± 0.27
OTU2 + OTU3 + OTU4245.07 ± 0.20
  • a Data are the means ± SD for triplicate cultures. The only culture that could be continuously transferred was the enrichment culture. The carbon source was 0.2 mM acetate for all cultures or combinations except the enrichment culture, in which dissolved inorganic carbon was the carbon source. All cultures contained 8 to 10 mM FeCl2·4H2O and 4 mM KNO3.