TABLE 4.
Fermentation characteristics of strain SK-FGG4 in the presence of glycerol as the sole carbon source at different oxygen concentrationsa
| Parameter | Fermentation conditions and product value |
|||
|---|---|---|---|---|
| Strict anaerobic (20:50)b | Microaerobic (20:100)b | Semiaerobic (20:200)b | Aerobic (20:300)b | |
| Fermentation time (h) | 48 ± 0.30 | 48 ± 0.30 | 48 ± 0.30 | 48 ± 0.30 |
| Total consumed glycerol (g/liter) | 0.3 ± 0.0 | 32.1 ± 1.8 | 54.0 ± 6.1 | 52.5 ± 01.1 |
| Rate of consumption (g liter−1 h−1) | 0.0 ± 0.0 | 0.67 ± 0.04 | 1.12 ± 0.13 | 1.1 ± 0.02 |
| Total ethanol produced (g/liter) | 0.0 ± 0.0 | 12.5 ± 0.8 | 21.0 ± 2.0 | 19.3 ± 0.4 |
| Rate of ethanol production (g liter−1 h−1) | 0.0 ± 0.0 | 0.26 ± 0.02 | 0.44 ± 0.05 | 0.40 ± 0.01 |
| Efficiency of ethanol production (ge/gs) | 0.0 ± 0.0 | 0.39 ± 0.01 | 0.39 ± 0.01 | 0.37 ± 0.01 |
| Efficient/theoretical (%) | 0.0 ± 0.0 | 78.0 ± 0.02 | 78.0 ± 0.2 | 74.0 ± 0.2 |
| Acetic acid accumulation (g/liter) | 0.0 ± 0.0 | 0.7 ± 0.1 | 2.90 ± 0.2 | 3.30 ± 0.04 |
| Total conversions (gp/gs) | 0.0 ± 0.0 | 0.41 ± 0.1 | 0.44 ± 0.1 | 0.43 ± 0.1 |
a
Fermentation was performed in triplicate, with each flask containing YNB medium supplemented with 69.0 ± 0.7 g/liter glycerol and 20 mg/liter leucine and histidine. Values represent the averages ± SD.
b
Oxygen availability in the flasks was measured as the ratio to yeast cells in the liquid medium; (liquid medium: flask volume) at 30°C with shaking at 200 rpm.