Table 2.
Comparison of biomass and metabolite production at the beginning of the stationary phase of batch culture and FSCFa
| Characteristic or metabolite | WA | B |
|---|---|---|
| Characteristic | ||
| Dry wt (g/liter) | 1.91 ± 0.04 | 1.91 ± 0.05 |
| Cell population (106 cells/ml) | 79 ± 4 | 86 ± 5 |
| Metabolites measured in: | ||
| g/liter | ||
| Succinate | 0.220 ± 0.005 | 0.230 ± 0.005 |
| Glycerol | 1.78 ± 0.05 | 1.93 ± 0.09 |
| Acetate | 0.230 ± 0.004 | 0.210 ± 0.006 |
| Ethanol | 13.5 ± 0.4 | 15.1 ± 0.6 |
| Pyruvate | 0.078 ± 0.005 | 0.090 ± 0.005 |
| mg/liter | ||
| Isoamyl alcohol | 52 ± 2 | 54 ± 4 |
| Isobutanol | 15.0 ± 0.7 | 15.1 ± 0.7 |
| Propanol | 7.6 ± 0.3 | 8.4 ± 0.4 |
| Ethyl acetate | 3.10 ± 0.07 | 3.3 ± 0.1 |
| μg/liter | ||
| Ethyl hexanoate | 21 ± 2 | 22 ± 1 |
| Ethyl octanoate | 40 ± 5 | ND |
| Ethyl decanoate | 52.3 ± 0.5 | 11.1 ± 0.8 |
| Ethyl dodecanoate | 6.5 ± 0.5 | ND |
| Isoamyl acetate | 41 ± 1 | 44 ± 2 |
| Isobutyl acetate | 5 ± 1 | ND |
a
Concentrations of metabolites and growth parameters were compared at an equivalent progression of fermentation (residual glucose, 164 ± 5 g/liter), between the third stage of FSCF without addition at steady state (WA), sampled after 3 residence times at steady state, and batch culture (B). Mean values and standard deviations were calculated from 3 independent FSCF or batch experiments. ND, not determined.