Table 4 The production of metabolites and hydrogen after 20 h anaerobic fermentation in serum bottles of gene expressing strains

Initial glucose (mM)

83.33

83.33

83.33

83.33

83.33

83.33

83.33

83.33

Residual sugar (mM)

32.50 ± 6.19

53.98 ± 2.13

35.16 ± 0.85

49.20 ± 0.87

29.65 ± 0.49

48.7 ± 1.73

36.42 ± 0.59

49.48 ± 1.02

Formic acid (mM)

15.70 ± 1.08

9.72 ± 2.49

16.49 ± 1.30

0

18.54 ± 1.30

5.62 ± 1.20

18.62 ± 0.83

0

Lactic acid (mM)

2.95 ± 0.28

2.87 ± 0.38

5.03 ± 0.12

3.79 ± 0.10

6.09 ± 0.03

2.88 ± 0.46

6.12 ± 0.05

3.66 ± 0.01

Acetic acid (mM)

5.65 ± 0.14

1.69 ± 0.15

6.49 ± 0.65

0.62 ± 0.40

5.37 ± 0.03

2.82 ± 0.83

4.29 ± 0.22

1.53 ± 0.02

Citric acid (mM)

0.11 ± 0.10

0.24 ± 1.71

0.16 ± 0.03

0.03 ± 0.02

0.59 ± 0.02

0.33 ± 0.05

0.28 ± 0.24

0

Acetoin (mM)

0.95 ± 0.52

0.97 ± 0.18

0.41 ± 0.16

1.22 ± 0.46

0.15 ± 0.26

4.68 ± 0.39

0.36 ± 0.15

0.59 ± 0.11

2,3-Butanediol (mM)

0.22 ± 0.13

0

1.96 ± 0.21

0

0.13 ± 0.48

0

2.51 ± 0.05

0

Ethanol (mM)

2.91 ± 0.56

2.61 ± 0.15

1.96 ± 0.21

2.66 ± 0.88

2.68 ± 0.80

4.68 ± 2.26

2.54 ± 0.05

1.68 ± 0.57

H₂ yield (mol/mol glucose)

2.21 ± 0.09

1.19 ± 0.02

2.29 ± 0.07

1.67 ± 0.01

2.33 ± 0.09

1.64 ± 0.24

2.63 ± 0.03

1.59 ± 0.03