Table 1.
Net anaerobic HONO and NO emissions from different Proteobacteria in the presence of initial nitrite or nitrate
| Proteobacteria | Strains | Genes encoding nitrogen oxide reductases converting | Maximum flux (ng m−2 s−1) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NO3− to NO2− | NO2− to NO | NO2− to NH4+ | NO to N2O | N2O to N2 | Nitrite | Nitrate | ||||||
| narG | napA | nirK | nirS | nirBDC/nrfAB | norBC | nosZ | HONO | NO | HONO | NO | ||
| Nitrate reducer | Escherichia coli K-12 | + | + | − | − | +a | − | − | 575 ± 115 | 165 ± 33 | 697 ± 139 | 258 ± 52 |
| Denitrifiers | Pseudomonas G-179 | − | + | + | − | − | + | − | −12 ± 2 | 96 ± 19 | 11 ± 2 | 39 ± 8 |
| Bradyrhizobium japonicum | − | + | + | − | − | + | + | −31 ± 6 | −13 ± 3 | 14 ± 3 | 16 ± 3 | |
| Rhodanobacter denitrificans | + | − | + | − | − | + | + | 4 ± 1 | 5 ± 1 | 0.1 ± 0 | 0 ± 0.1 | |
| Pseudomonas stutzeri JM-300 | + | + | − | + | − | + | + | −37 ± 7 | −31 ± 6 | 0.7 ± 0.1 | 0.6 ± 0.1 | |
+ and − indicate that the bacteria have or do not have the specific denitrification-associated gene, respectively. Nitrogen mass-based maximum fluxes of HONO and NO were calculated by the differences between the maximum flux from pure cell culture and sterilized background medium, and can be attributed to the direct effect of the bacteria. Values are the maximum fluxes ± relative errors. Relative errors were calculated based on 20% of the flux value, which were derived from four replications of sterilized background measurement.
aAlternative nitrite reductases, see Fig. 3