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Table 2 pH-controlled batch fermentations of C. celer on 10 g/l of glucose at pH 7 and 6, with and without N 2 sparging

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

 

pH 7

pH 6

N2sparging ( Case I)

No sparging ( Case II)

N2sparging ( Case III)

No sparging ( Case IV)

P H2max (kPa)

8

69

6

74

μ max (h-1)

1.09 ± 0.09

1.09 ± 0.08

0.43 ± 0.03

0.38 ± 0.05

Biomass concentration (g/l)

0.99 ± 0.03

1.13 ± 0.01

1.02 ± 0.03

1.01 ± 0.01

YX/ATP (gCDW/mol ATP)

11.5 ± 0.3

9.3 ± 0.1

6.3 ± 0.4

7.9 ± 0.2

YATP/S (mol ATP/mol glucose)

3.24 ± 0.03

3.18 ± 0.02

3.4 ± 0.08

3.48 ± 0.17

Q H2 (mmol H2/l/h)

27.1 ± 1.5

33.0 ± 0.1

19.9 ± 0.8

20.6 ± 0.5

Product yield (mol/mol glucose)

    

   YX a

0.71 ± 0.01

0.75 ± 0.03

0.72 ± 0.01

0.75 ± 0.01

   YH2 a

2.32 ± 0.13

2.06 ± 0.13

3.10 ± 0.06

2.60 ± 0.03

   YA a

1.24 ± 0.01

1.28 ± 0.01

1.47 ± 0.07

1.35 ± 0.02

   YF a

0.37 ± 0.02

0.71 ± 0.12

0.14 ± 0.07

0.33 ± 0.06

   YE a

0.27 ± 0.01

0.37 ± 0.01

0.10 ± 0.01

0.39 ± 0.03

RVEP b

2.87 ± 0.11

2.8 ± 0.12

3.31 ± 0.08

3.39 ± 0.03

HAc/EtOH

4.5 ± 0.2

3.5 ± 0.1

14.2 ± 1.0

3.4 ± 0.3

Carbon recovery (%)

92.6 ± 0.6

94.0 ± 0.7

94.8 ± 4.2

100.3 ± 1.9

Redox recovery (%)

90.0 ± 0.6

97.5 ± 0.6

93.2 ± 4.1

102.3 ± 2.2

  1. aY indicates the yield of product (where x=biomass, H2=hydrogen, A=acetate, F=formate and E=ethanol) per mole of glucose consumed.
  2. bTotal 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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