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Table 2 The COD balance for phases II-A, II-B and II-C in Experiment II*

From: Steering the product spectrum in high-pressure anaerobic processes: CO2 partial pressure as a novel tool in biorefinery concepts

Sample

Phase

Acetate (mg COD)

Propionate (mg COD)

Butyrate (mg COD)

CH4 (mg COD)

Succinate (mg COD)

Others (mg COD)

Biomassa (mg COD)

Total (mg COD)

COD fed (mg)

Recovered fraction from COD substrateb

Recovered fraction from COD substrate (included solubilized COD)c

COD fed + carry over from previous phase (mg)

Recovered fraction from COD substrate + carry overd

GG_CO2 (n = 3)

II-A

25.26 ± 8.6

221.18 ± 31.3

163.86 ± 31.3

142.80 ± 23.9

0.00 ± 0.0

3.31 ± 3.1

0.00 ± 0.0

556.41 ± 56.7

762 ± 28

0.73 ± 0.1

0.73 ± 0.1

779.21 ± 26.9

0.71 ± 0.1

II-B

20.57 ± 2.9

224.44 ± 32.9

20.11 ± 59.9

144.51 ± 16.2

0.00 ± 0.0

7.06 ± 2.3

123.92 ± 45.2

540.60 ± 88.6

935 ± 143

0.58 ± 0.1

0.71 ± 0.1

1150.08 ± 78.6

0.47 ± 0.1

II-C

12.26 ± 2.4

155.70 ± 41.5

0.00 ± 0.0

169.66 ± 70.7

55.20 ± 6.4

5.50 ± 2.7

147.11 ± 42.0

545.43 ± 142.9

586 ± 40

0.93 ± 0.3

0.93 ± 0.3

1032.26 ± 65.3

0.53 ± 0.1

GLY_CO2 (n = 1)

II-A

24.39

497.24

4.53

36.86

0.00

3.36

0.00

566.38

806

0.70

0.70

814.03

0.70

II-B

40.18

310.46

14.02

13.88

0.00

3.44

158.36

540.34

722

0.75

0.92

1226.81

0.44

II-C

84.02

410.60

0.00

47.28

13.53

2.92

94.42

652.79

582

1.12

1.12

1129.64

0.53

GLU_CO2 (n = 1)

II-A

29.89

94.19

206.14

126.83

0.00

4.83

0.00

461.89

724

0.64

0.64

745.14

0.62

II-B

6.44

41.18

261.65

128.86

0.00

5.97

71.45

515.56

768

0.67

0.81

1098.94

0.47

II-C

36.91

16.00

244.83

101.94

0.00

4.79

103.14

507.60

581

0.87

0.87

1071.78

0.47

GG_N2 (n = 1)

II-A

20.38

191.72

23.73

222.17

0.00

3.34

0.00

461.34

713

0.65

0.65

728.69

0.63

II-B

9.14

145.75

0.00

219.17

0.00

2.57

50.69

427.32

862

0.50

0.62

1216.32

0.35

II-C

87.79

171.39

0.00

124.81

0.00

2.57

253.33

639.89

617

1.04

1.04

846.69

0.76

  1. *Data are presented for mix substrate treatments (GG_CO2) at 5 bar pCO2, mix substrate control at 5 bar pN2 (GG_N2) and single substrate controls (glucose GLU_CO2 and glycerol GLY_CO2). The standard deviation of three biological replicates is included only in the case of GG_CO2 treatments
  2. aBiomass was calculated as the difference between initial and final VSS concentration in each phase and converted to COD using a conversion factor of 1.42 g COD/g VSS
  3. bThis fraction corresponds to the COD recovered as end of phase (EoP) products considering only the soluble COD from the substrate
  4. cThis fraction corresponds to the COD recovered as end of phase (EoP) products considering that a theoretical 80% of the COD from decay in phase II-A became solubilized into phase II-B
  5. dThis fraction corresponds to the COD recovered as end of phase (EoP) products considering COD from substrate and carried-over carboxylates/organic acids from the immediate previous phase