Table 1.
Synthesis of UDP-GlcA from starch through a cascade using whole cells expressing hyperthermophilic enzymes
| Entry | Pro . | Sub. | Sub. conc. (mM) | NAD+ (mM) | UTP (mM) | Whole-cells (DCW, g/L) | Time (h) | Conv. of sub. (%) | Conc. of product (mM) | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1a | G1P | Starch | 5% (w/v) | – | – | TmαGP (9.2) | – | – | – | – | 6 | 22 | 40 |
| 2b | UDP-Glc | G1P | 10 | – | 10 | TmαGP (2.3) | StUSP (13.6) | – | – | – | 3 | 46 | 4.6 |
| 3c | UDP-GlcA | UDPG | 2.3 | – | – | TmαGP (1.1) | StUSP (6.8) | PiUDH (14.6) | – | – | 0.5 | 52 | 1.2 |
| 4c | UDP-GlcA | UDPG | 2.3 | 0.1 | – | TmαGP (1.1) | StUSP (6.8) | PiUDH (14.6) | – | – | 0.5 | 100 | 2.3 |
| 5c | UDP-GlcA | UDPG | 2.3 | – | – | TmαGP (1.1) | StUSP (6.8) | PiUDH (14.6) | TkNOX (8.8) | – | 0.5 | 100 | 2.3 |
| 6c | UDP-GlcA | UDPG | 2.3 | – | – | TmαGP (1.1) | StUSP (6.8) | – | – | PiUDH-TkNOX (17.8) | 0.5 | 100 | 2.3 |
Data are the average of triplicate measurements
aEntry 1 was incubated in a reaction mixture (pH 7.0) at 70 °C for 6 h
bEntry 2 was incubated in a reaction mixture (pH 9.0) at 80 °C for 3 h
cEntries 3, 4, 5 and 6 were incubated in a reaction mixture (pH 10.0) at 65 °C for 0.5 h