Table 1.
Nitrogen balance of the “Ca. Na. tergens” sp. RJ19 enrichment culture supplied with NH4+ or urea.
| NH4+ fed (mmol/day) | NO2- (mmol/day) | NO3- (mmol/day) | NH4+ not consumed (mmol/day) | NO/NO2 (mmol/day) | Protein-N (mmol/day) | Total N (mmol/day) | Recovery (%) |
|---|---|---|---|---|---|---|---|
| 76.2 ± 1.1 | 5.2 ± 0.5 | 30.6 ± 2.7 | 17.7 ± 4.4 | 14.4 ± 1.0 | 0.5 ± 0.0 | 68.4 ± 8.6 | 90 ± 11 |
| Urea fed (mmol/day) | Urea not consumed (mmol/day) | ||||||
|---|---|---|---|---|---|---|---|
| 31.1 ± 0.0 | 1.3 ± 0.0 | 2.4 ± 0.0 | 27.7 ± 0.5 | 4.8 ± 0.1 | 0.4 ± 0.1 | 36.7 ± 0.6 | 118 ± 2 |
The table shows the amount of substrate (NH4+ or urea) fed to the reactor and the nitrogen products formed (NO2−, NO3−, NO/NO2). The amount of nitrogen utilized for biomass production is also calculated (protein-N), together with total Nitrogen (Total N). The resulting nitrogen recovery is expressed in %. Values are shown as average ± standard deviation (n = 3). NH4+-feeding experiments were performed in chemostat mode, while urea-fed experiments were performed in the exponential phase of a batch reactor over an 8-h time period.