TABLE 1.
Growth rates, substrate consumption rates, YX/S, final l-valine concentrations, and by-product concentrations in shake flask fermentations of C. glutamicum ΔaceE Δpqo(pJC4ilvBNCE) and C. glutamicum ΔaceE Δpqo ΔsugR(pJC4ilvBNCE)a
| Strain | Substrates | Growth rate (h−1) | Substrate consumption rate [mmol/(g CDW × h)]b
|
YX/S (g CDW/mol C)c | Final l-valine concn (mM) | By-product (mM)
|
|||
|---|---|---|---|---|---|---|---|---|---|
| Acetate or ethanol | Glucose | l-Alanine | Pyruvate | l-Lactate | |||||
| C. glutamicum ΔaceE Δpqo(pJC4ilvBNCE) | Glucose + acetate | 0.38 ± 0.02 | 3.30 ± 0.30 | 0.18 ± 0.04 | 19 ± 3 | 106 ± 9 | <1 | 13 ± 5 | <1 |
| C. glutamicum ΔaceE Δpqo ΔsugR(pJC4ilvBNCE) | Glucose + acetate | 0.31 ± 0.02 | 1.90 ± 0.10 | 0.80 ± 0.05 | 38 ± 7 | 63 ± 4 | 5 ± 2 | 14 ± 6 | 47 ± 10 |
| C. glutamicum ΔaceE Δpqo(pJC4ilvBNCE) | Glucose + ethanol | 0.31 ± 0.02 | 1.80 ± 0.12 | 1.05 ± 0.08 | 36 ± 7 | 93 ± 6 | 5 ± 2 | 3 ± 1 | <1 |
a
Values are means ± standard deviations.
b
Cell dry weight (CDW) was calculated from the OD600 (after 8 h) using a ratio of 0.3 g CDW liters−1 per OD600 (4). Substrate consumption rates were calculated for acetate, ethanol, and glucose for the first 8 h of fermentation.
c
YX/S is given as g CDW per mol C from either acetate or ethanol.