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Table 1 pH-controlled batch fermentations of C. celer on 5 g/l of glucose at different culture pH

From: Assessment of metabolic flux distribution in the thermophilic hydrogen producer Caloramator celer as affected by external pH and hydrogen partial pressure

  

pH

 
 

8

7

6

5.5

μ max (h-1)

1.50 ± 0.05

1.34 ± 0.05

0.53 ± 0.01

0.45 ± 0.06

Biomass concentration (gCDW/l)

0.95 ± 0.01

0.95 ± 0.06

0.76 ± 0.01

0.42 ± 0.01

q glucose a (mmol/gCDW/h)

19.6 ± 1.4

20.6 ± 0.1

14.3 ± 0.1

14.0 ± 0.2

YX/ATP (gCDW/mol ATP)

15.4 ± 0.7

15.2 ± 0.4

6.8 ± 0.2

6.0 ± 0.4

YATP/S (mol ATP/mol glucose)

2.81 ± 0.02

3.05 ± 0.03

3.54 ± 0.33

3.60 ± 0.09

H2 accumulation (mmol H2/l)

68.0 ± 1.3

64.2 ± 1.1

106.0 ± 2.3

91.7 ± 0.4

Q H2 (mmol H2/l/h)

25.2 ± 1.2

21.0 ± 1.3

14.9 ± 0.2

13.0 ± 0.9

Product yield (mol/mol glucose)

    

  YX b

1.29 ± 0.05

1.37 ± 0.07

1.04 ± 0.01

0.62 ± 0.02

  YH2 b

1.90 ± 0.01

1.69 ± 0.03

2.97 ± 0.10

2.48 ± 0.03

  YA b

1.04 ± 0.01

1.02 ± 0.04

1.33 ± 0.08

1.28 ± 0.04

  YF b

0.45 ± 0.01

0.37 ± 0.11

0.14 ± 0.02

0.19 ± 0.01

  YE b

0.35 ± 0.01

0.48 ± 0.05

0.20 ± 0.01

0.36 ± 0.03

RVEP c

2.60 ± 0.03

2.65 ± 0.13

3.36 ± 0.09

3.19 ± 0.02

HAc/EtOH

2.96 ± 0.11

2.15 ± 0.30

6.83 ± 0.67

3.60 ± 0.14

Carbon recovery (%)

88.6 ± 1.1

99.8 ± 1.5

100.7 ± 2.8

93.5 ± 1.6

Redox recovery (%)

94.4 ± 0.6

99.2 ± 0.7

98.4 ± 3.2

93.6 ± 2.1

  1. aSpecific glucose consumption rate measured during exponential phase.
  2. bY indicates the yield of product (where x=biomass, H2=hydrogen, A=acetate, F=formate and E=ethanol) per mole of glucose consumed.
  3. cTotal molar reduction values of reduced end-products (RVEP = YH2 + 2 * YE) [19].
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Microbial Cell Factories

ISSN: 1475-2859

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