Table 2.
Physiological characteristics of monocultures and cocultures of S. cerevisiae and Lb. delbrueckii subsp. bulgaricusa
| Characteristic | Value for: |
||
|---|---|---|---|
| Coculture | S. cerevisiae | Lb. delbrueckii subsp. bulgaricus | |
| Concentrations | |||
| Biomasstotal (g · liter−1) | 2.82 ± 0.08 | 1.46 ± 0.03 | 1.45 ± 0.08 |
| Biomassyeast (g · liter−1) | 1.41 ± 0.07 | 1.46 ± 0.03 | |
| BiomassLAB (g · liter−1) | 1.41 ± 0.02 | 1.45 ± 0.08 | |
| Reservoir sugar concn (mM) | 74.2 ± 1.8 | 67.8 ± 0.4b | 70.2 ± 7.1 |
| Residual lactose concn (mM) | 0.15 ± 0.07 | 2.1 ± 0.7 | |
| Residual glucose concn (mM) | 0.34 ± 0.04 | NDd | 0.54 ± 0.4 |
| Residual galactose concn (mM) | 1.57 ± 0.08 | 1.0 ± 0.1 | 63.0 ± 2.2 |
| Yields and ratesc | |||
| YLAB/glucose(gdry LAB · gglucose−1) | 0.11 ± 0.00 | 0.13 ± 0.02 | |
| YLAB/lactose (gdry LAB · glactose−1) | 0.06 ± 0.00 | 0.06 ± 0.01 | |
| Ylactate/lactose (mollactate · mollactose−1) | 1.63 ± 0.07 | 1.8 ± 0.3 | |
| qlactose (mmol · gdry LAB−1 · h−1) | 5.7 ± 0.2 | 4.7 ± 0.7 | |
| Yyeast/galactose (gdry yeast · ggalactose−1) | 0.11 ± 0.01 | 0.12 ± 0.00 | |
| Yethanol/galactose(molethanol · mollactose−1) | 1.57 ± 0.08 | 1.72 ± 0.01 | 0.00 ± 0.00 |
| Yglycerol/galactose(molglycerol · molgalactose−1) | 0.15 ± 0.03 | 0.13 ± 0.02 | 0.00 ± 0.00 |
| qgalactose (mmol · gdry yeast−1 · h−1) | NEe | 4.9 ± 0.3 | |
| qCO2 (mmol · gdry yeast−1 · h−1) | 10.2 ± 0.5 | 9.67 ± 1.05 | |
| qethanol (mmol · gdry yeast−1 · h−1) | 8.7 ± 0.2 | 8.4 ± 0.5 | |
| qglycerol (mmol · gdry yeast−1 · h−1) | 0.8 ± 0.2 | 0.7 ± 0.1 | |
| qacetate (mmol · gdry yeast−1 · h−1) | 0 | 0.01 ± 0.00 | |
| Yx/lactose (gtotal biomass · glactose−1) | 0.11 ± 0.01 | 0.06 ± 0.01 | |
| Ylactate/galactose (mollactate · molgalactose−1) | 0.02 ± 0.02 | 0 | |
| qpyruvate (mmol · gtotal biomass−1 · h−1) | 0.01 ± 0.00 | 0.02 ± 0.02 | 0.02 ± 0.01 |
| qsuccinate (mmol · gtotal biomass−1 · h−1) | 0.07 ± 0.01 | 0.01 ± 0.00 | 0.28 ± 0.09 |
| qlactate (mmol · gtotal biomass−1 · h−1) | 9.2 ± 0.4 | 0.04 ± 0.02 | 8.3 ± 0.6 |
| % carbon recovery | 98.9 ± 4.1 | 111.3 ± 2.2 | 98.6 ± 13.9 |
a
S. cerevisiae and Lb. delbrueckii subsp. bulgaricus were grown anaerobically in a carbon-limited chemostat at a dilution rate of 0.10 h−1. For each condition, averages and standard deviations were obtained from triplicate independent chemostat cultures.
b
Galactose.
c
Y, yield; q, biomass-specific rate.
d
ND, not detected.
e
NE, not estimated.