Table 1 Fermentation characteristics for Saccharomyces cerevisiae CEN.PK113-7D and the two mutant strains during anaerobic fed-batch fermentation at 30°C

Fermentation time (h)

70

146

167

Growth time (h)

24

60

133

μmax (h^-1)

0.29 ± 0.01

0.13 ± 0.01

0.046 ± 0.001

DCWmax (g L^-1)

12.0 ± 0.5

8.0 ± 0.5

3.8 ± 0.2

Y DCW/glucose g g^-1

0.076 ± 0.001

0.074 ± 0.003

0.055 ± 0.001

[0–16 h]

[0–30 h]

[0–44 h]

Y glycerol/glucose g g^-1

0.056 ± 0.001

0.031 ± 0.003

0.022 ± 0.004

[0–16 h]

[0–30 h]

[0–44 h]

Y glycerol/DCW g g^-1

0.74 ± 0.03

0.42 ± 0.02

0.40 ± 0.04

[0–16 h]

[0–30 h]

[0–44 h]

Y acetate/ glucose g g^-1

0.005 ± 0.001

n.d.

n.d.

Y pyruvate/ glucose g g^-1

0.003 ± 0.001

n.d.

n.d.

Y succinate/ glucose g g^-1

0.004 ± 0.001

0.013 ± 0.001

0.026 ± 0.001

Yethanol/glucose g g^-1 (growth)

0.45 ± 0.003

0.46 ± 0.008

0.48 ± 0.005

Yethanol/glucose g g^-1 (overall)

0.47 ± 0.001

0.48 ± 0.003

0.48 ± 0.005

[ethanol] final (g L^-1)

139 ± 1

106.0 ± 0.5

57 ± 2

[glycerol] final (g L^-1)

9.0 ± 0.3

5.4 ± 0.1

2.8 ± 0.2

Ethanol productivity (g L^-1 h^-1)

1.97 ± 0.10

0.73 ± 0.03

0.33 ± 0.02

Pcritical (g L^-1)

90 ± 2

78 ± 1

54 ± 2