TABLE 3.
Results for pH-regulated batch cultures of the fnr mutant and its parent strain, B. cereus F4430/73a
| Parameter or yield | Value for anaerobic growth with nitrate
|
|||
|---|---|---|---|---|
| 20 mM
|
60 mM
|
|||
| WT | fnr | WT | fnr | |
| Initial ORP (mV) | +150 | +150 | +170 | +170 |
| Final ORP (mV) | +20 | +60 | +30 | +70 |
| Growth parameters | ||||
| μmax (h−1) | 0.8 | 0.4 | 0.9 | 0.8 |
| Final biomass (g/liter) | 0.5 | 0.2 | 0.6 | 0.6 |
| Glycerol consumed (%) | 75 | 75 | 91 | 91 |
| Nitrate consumed (%) | 100 | 100 | 99 | 99 |
| Residual nitrite (mM) | NZ | NZ | 0.04 | 0.05 |
| Yields of end products (mol/mol of glycerol) | ||||
| Biomass | 0.11 | 0.05 | 0.11 | 0.11 |
| Lactate | NZ | NZ | NZ | NZ |
| Acetate | 0.32 | 0.11 | 0.35 | 0.15 |
| Formate | 0.06 | 0.04 | 0.02 | 0.03 |
| Ethanol | NZ | NZ | NZ | NZ |
| Succinate | NZ | NZ | 0.03 | 0.10 |
| Carbon recovered (%) | 34 | 12 | 37 | 27 |
| Oxidation state balance | +0.41 | +0.14 | +0.56 | −0.11 |
a
Cultures were grown under anaerobic conditions on MOD medium with 60 mM glycerol as the carbon source and nitrate as the electron acceptor. Values are means of results for triplicate cultures. For clarity, standard deviations (below 10%) are not shown. Data are presented as described in the footnotes to Table 2. WT, wild type (B. cereus F4430/73); fnr, fnr mutant; NG, no growth; NZ, yield near zero or below 0.01.