Table 1 A comparison of different ivSEBs for PHB production

From: ATP-free in vitro biotransformation of starch-derived maltodextrin into poly-3-hydroxybutyrate via acetyl-CoA

Source of carbon

Need of ATP

Source of ATP

Source of NADPH

NADPH regeneration method

Theoretical system performance

Reaction mode

Actual system performance

Ref.

Carbon conversion efficiency

Molar yield of PHB

Substrate concentration

Final product titer

Molar yield of PHB

Total reaction time

PHB production rate

Acetate

Yes

Direct addition

Glucose

GDH

100.0%

50.0%

One pot,

one step

30.0 mM

9.3 mM[a] (0.8 g/L)

31.0%

24 h

0.4 mM/h

( < 0.1 g/L/h)

23

One pot,

one step

60.0 mM

12.8 mM[a] (1.1 g/L)

21.3%

24 h

0.5 mM/h

( < 0.1 g/L/h)

Acetate

Yes

ATP regeneration by thylakoid membranes

Light

Thylakoid membrane

100.0%

50.0%

One pot,

one step

10.0 mM

4.3 mM (0.4 g/L)[b]

43.0%

Around 34 h

Around 0.1 mM/h

( < 0.1 g/L/h)

24

One pot,

five steps[c]

50.0 mM

20.0 mM (1.7 g/L)[b]

40.0%

36 h

0.6 mM/h

( < 0.1 g/L/h)

Methanol

No

N/A

Methanol

FDH

80.0%

20.0%

One pot,

one step

20.0 mM

3.9 mM (0.3 g/L)[b]

19.5%

6.5 h

0.6 mM/h

( < 0.1 g/L/h)

26

Two pots, three steps[d]

20.0 mM

69.8 mM[a] (6.0 g/L)

20.5%

Not clear[e]

Cannot be calculated

Pyruvate

No

N/A

Pyruvate

PDH (with a purge valve)

66.7%

50.0%

One pot,

one step

50.0 mM

29.1 mM[a] (2.5 g/L)

58.2%

15 h

1.9 mM/h

(0.2 g/L/h)

27

Glucose

Yes

ATP regeneration from glucose

Glucose

G6PDH, 6PGDH

(with purge valves)

88.9%[f]

133.3%[f]

One pot, three steps[g]

60.7 mM

56.8 mM (4.9 g/L)[b]

93.6%

30 h

1.9 mM/h (0.2 g/L/h)

28

One pot,

five steps[g]

109.2 mM

93.8 mM (8.1 g/L)[b]

85.9%

55 h

1.7 mM/h (0.1 g/L/h)

Starch-derived maltodextrin

No

N/A

Starch-derived maltodextrin

G6PDH, 6PGDH

(no purge valve)

88.9%

133.3%

One pot,

one step

101.4 mM

74.9 mM (6.4 g/L)[b]

125.5%

8 h

9.4 mM/h (0.8 g/L/h)

This study

One pot,

two steps

100.0 mM

118.8 mM (10.2 g/L)[b]

120.1%

24 h

5.0 mM/h (0.4 g/L/h)

One pot,

two steps

198.4 mM

208.3 mM (17.9 g/L)[b]

111.9%

24 h

8.7 mM/h (0.7 g/L/h)

  1. [a] Results provided in mM were calculated from the data in g/L based on the molecular weight (86) of the monomer of PHB.
  2. [b] Results provided in g/L were calculated from the data in mM based on the molecular weight (86) of the monomer of PHB.
  3. [c] In the first step, 10 mM substrate was added. In each of the remaining steps, PHB was removed from the reaction mixture, followed by the addition of PhaC, thylakoid membranes, and another 10 mM substrate.
  4. [d] The three steps are (1) the conversion of 20 mM methanol to glycolaldehyde by a 1-L system; (2) the concentration of the reaction solution to 58.8 mL, which contained 135.6 mM glycolaldehyde, and (3) the conversion of concentrated glycolaldehyde to PHB.
  5. [e] The timings of the first two steps were not provided in the reference. The reaction time of the third step was 5 h.
  6. [f] Theoretical carbon conversion efficiency provided by the reference article was 66.6%, corresponding to a theoretical PHB molar yield of 100.0%. However, we suggest these numbers be 88.9% and 133.3%, respectively. Explanation refers to the Discussion section.
  7. [g] In the first step, the reaction was initiated by a single addition of substrate. In each of the remaining steps, PHB was removed from the reaction mixture by centrifugation, followed by the addition of PhaC.
Back to article page