TABLE 1.
IC consumption during continuous chemostat culturea
| Na2CO3 treatment | IC in culture (mM) | CO2 in effluent air (μM)b | IC contributed by pH control (μmol liter−1 h−1)c | IC consumed from medium (μmol liter−1 h−1)d | CO2 consumed from air (μmol liter−1 h−1)d | Total IC consumed (μmol liter−1 h−1)d |
|---|---|---|---|---|---|---|
| Replete | 3.49 (1.06) | 29.1 (2.42) | —e | — | — | 74.6e |
| 1.0 mM | 0.57 (0.11) | 8.15 (0.97) | 3.14 (0.06) | 10.6 | 12.6 | 23.2 |
| 0.2 mM | 0.13 (0.02) | 7.35 (0.98) | 2.38 (0.005) | 4.80 | 16.3 | 21.1 |
Values are the means of results from three biological replicates. Values in parentheses are the standard deviations of the means.
Values are based on 400 ppm or approximately 16.5 μM CO2 in the atmosphere under standard conditions.
IC contributions from the background IC in the NaOH addition to control pH are based on the flow rate and on an IC concentration of 0.60 mM.
The average rate of consumption is based on the weighted average of the IC in the culture and the IC contributed by an added pH control to the total reduction in atmospheric CO2 (estimated to be 400 ppm in atmosphere; 49.6 μmol h−1 was supplied in air).
—, the IC contribution from a pH control and after consumption from the medium and air in the IC-replete treatment was not calculated. A value of 74.6 μmol liter−1 h−1 should theoretically be consumed based on the NH3 oxidation rate (30).