Table 1 Comparison of simulation predictions from the discrete and continuous microPop:Colon models

pH

6.4

6.4

5.7

5.7

6.37, 6.61, 7.04 (66 non-fasted subjects)

4.9/5.8, 6.2/5.7, 6.7/6* (2 recently deceased subjects)

Mean 6.5, range 5-8 (20 fasted subjects)

[16]

[18]

[17]

6.8

6.8

5.8

5.7

7.1

7.1

6.3

6.3

SCFA concentrations (mM)

 Acetate concentration

15.4

15.9

23.1

24

97.5/98*^

[18]

11.7

12.9

26.7

33

78.4/74.6*^

7.8

11

15.3

19.1

53.8/50.7*^

 Propionate concentration

7.6

7.5

13.6

8.6

34.5/30*^

[18]

5.7

5.7

15.2

11.4

26.7/28.5*^

4.1

4.4

7.2

5.7

17.9/19.2*^

 Butyrate concentration

0.3

0.2

5.6

7.7

41.5/36*^

[18]

0.6

0.2

8.1

9.3

35.8/32.1*^

1.3

0.4

3.9

4.2

16.4/25.8*^

 SCFA ratio (Acetate: Propionate: Butyrate)

66:33:1

67:32:1

55:32:13

60:21:19

56:20:24/60:18:22*

[18]

65:32:3

69:30:1

54:30:16

62:21:17

56:19:25/55:21:24*

59:31:10

70:28:2

58:27:15

66:20:14

61:20:19/53:20:27*

SCFA absorption (g d^-1)

 Acetate

2.11

2.56

4.54~

5.45~

95% (≃9.4 g d^-1 total for Alpha discrete and ≃13 g d^-1 total for Beta discrete; ≃16.3 g d^-1 total for Alpha continuous and ≃17.3 g d^-1 total for Beta discrete) of total produced SCFAs

[19]

 Propionate

1.63

1.66

3.64~

2.78~

 Butyrate

0.43

0.15

2.81~

3.27~

 Total

4.17

4.37

10.99

11.5

 MFG relative abundance (%)^#

 Bacteroides

98

97

48

27

23 (mean value; Bacteroidetes)

11 (mean value; Bacteroides)

16, 35 (mean values using different techniques; Bacteroidetes)

26, 3 (mean values; lean, obese individuals; Bacteroidetes)

[67]

[68]

[69]

[70]

95

95

42

24

88

89

42

25

 NoButyStarchDeg

<1e−10

<1e−10

0.2

0.2

4 (mean value; Ruminococcus bromii)

[71]

<1e−10

<1e−10

0.1

0.2

<1e−10

1e−10

0.1

0.2

 NoButyFibreDeg

<1e−10

<1e−10

0.1

0.2

11, 27 (mean values; lean, obese individuals; Ruminococcus)

[70]

<1e−10

<1e−10

0.2

0.2

<1e−10

<1e−10

0.2

0.2

 LactateProducers

<1e−10

1.8

20

36

5 (mean value; Actinobacteria)

4 (mean value; Actinobacteria)

2, 5 (mean values using different techniques; Bifidobacteria)

<1, 4 (mean values; lean, obese individuals; Actinobacteria)

[67]

[68]

[69]

[70]

<1e−10

3.5

21

39

<1e−10

7

21

39

 ButyrateProducers1

<1e−10

0.9

16

22

3 (mean value; Roseburia)

4 (mean values; Roseburia intestinalis)

[67]

[72]

<1e−10

2

19

23

<1e−10

4

19

23

 ButyrateProducers2

2

<1e -10

2

1

5 (mean value; Faecalibacterium)

2 (mean value; Faecalibacterium prausnitzii)

[67]

[72]

4

<1e−10

2

1

11

<1e−10

3

1

 PropionateProducers

<1e−10

<1e−10

14

13

4, 4 (mean values using different techniques; Veillonella)

[69]

0.2

0.2

15

11

0.5

0.7

15

11

 ButyrateProducers3

<1e−10

<1e−10

0.1

0.1

0.04 (mean value; Eubacterium hallii)

0.5 (mean value; Eubacterium hallii)

[73]

[72]

0.001

0.003

0.1

0.09

0.004

0.004

0.1

0.08

 Acetogen

<1e−10

<1e−10

0.04

0.04

Found in all regions

of the colon, but

abundance varies slightly between regions and individuals (10⁴-10⁵ gene copies g^-1 in mucosal biopsies). More abundant than methanogens and SRB in faeces.

1 (mean value; Blautia)

[44]

[74]

[67]

<1e−10

<1e−10

0.05

0.03

<1e−10

<1e−10

0.05

0.03

 Methanogen

<1e−10

<1e−10

0.05

0.06

Found in all individuals, but not found in all regions of each individual. Increased population size distally.

[44]

<1e−10

<1e−10

0.03

0.06

0.06

0.01

0.04

0.2

 SRB

<1e−10

<1e−10

0.05

0.05

Found in all regions of the colon, but abundance varies widely between regions and individuals (10²-10⁹ gene copies g⁻¹ in mucosal biopsies)

0.02 (mean value; Desulfovibrio)

0.1, 0.03 (mean values; lean, obese individuals; Desulfovibrio)

[44]

[75]

[70]

<1e−10

<1e−10

0.04

0.04

<1e−10

<1e−10

0.06

0.05