TABLE 1.
Specific growth rates, biomass yields, and metabolic fluxes in aerobic and anaerobic cultures of Z. bailii, C. utilis, and S. cerevisiaea
| Medium | Conditions | Organism | Specific growth rate (h−1) | Biomass yield (g of biomass · g of glucose−1) | Metabolic fluxes (mmol · g of biomass−1 · h−1)
|
||
|---|---|---|---|---|---|---|---|
| Glucose | Ethanol | Glycerol | |||||
| Defined | Aerobic | Z. bailii | 0.25 ± 0.02 | 0.29 ± 0.01 | 4.7 ± 0.1 | 3.5 ± 0.1 | 0.10 ± 0.01 |
| C. utilis | 0.53 ± 0.02 | 0.53 ± 0.01 | 5.5 ± 0.1 | <0.01 | <0.01 | ||
| S. cerevisiae | 0.29 ± 0.01 | 0.12 ± 0.01 | 13 ± 1 | 19 ± 4 | 0.09 ± 0.06 | ||
| Anaerobic | Z. bailii | 0.03–0.08b | 0.07 | 1.9–6.4 | 2.6–9.4 | 0.3–1.1 | |
| C. utilis | 0.01–0.03b | 0.05 | 1.1–3.3 | 1.6–4.6 | 0.2–0.6 | ||
| S. cerevisiae | 0.27 ± 0.01 | 0.10 ± 0.01 | 15 ± 1 | 24 ± 1 | 2.7 ± 0.3 | ||
| Complex YPD | Anaerobic | Z. bailii | 0.09 ± 0.01 | 0.09 ± 0.01 | 5.6 ± 0.2 | 9.5 ± 0.9 | |
| S. cerevisiae | 0.17 ± 0.01 | 0.07 ± 0.004 | 13 ± 1 | 22 ± 1 | |||
a
Cells were grown on 20 g of glucose per liter in defined and complex YPD media in pH-controlled fermentors (pH 3.0). The data for aerobic Z. bailii and S. cerevisiae cultures are from the respirofermentative parts of the growth curves. Unless indicated otherwise, data are averages ± standard deviations based on duplicate independent experiments.
b
Range calculated along the linear growth curve (μ = dx/xdt, where μ is the specific growth rate and dx/dt is constant). Data obtained in three independent experiments differed by less than 10%.