Table 3. Optimization of Reaction Conditions for Reduction of Compound 4 by 3α-HSDHa.
| entry | solvent | 3α-HSDb(400 g/L) | GDHb (400 g/L) | gluconate/H2O | NAD+ (g) | yield (%)b | conversionc |
|---|---|---|---|---|---|---|---|
| 1 | t-butanol (25 mL) | 5 mL | 5 mL | 5 g/15 mL | 0.025 | 89 | 100% (1 h) |
| 2 | Isopropanol (25 mL) | 5 mL | 5 mL | 5 g/15 mL | 0.025 | 65 | 80% (1 h) |
| 3 | Ethyl acetate (25 mL) | 5 mL | 5 mL | 5 g/15 mL | 0.025 | / | 20% (1 h) |
| 4 | t-butanol (25 mL) | 4 mL | 4 mL | 5 g/15 mL | 0.025 | 92 | 100% (1.5 h) |
| 5 | t-butanol (25 mL) | 3 mL | 3 mL | 5 g/15 mL | 0.025 | 93 | 100% (1 h) |
| 6 | t-butanol (30 mL) | 3 mL | 3 mL | 5 g/15 mL | 0.025 | 80 | 90% (1 h) |
| 7 | t-butanol (35 mL) | 3 mL | 3 mL | 5 g/15 mL | 0.025 | 92 | 100% (1 h) |
| 8 | t-butanol (35 mL) | 3 mL | 3 mL | 4.5 g/15 mL | 0.015 | 93 | 100% (1 h) |
| 9 | t-butanol (35 mL) | 3 mL | 3 mL | 4.0 g/15 mL | 0.015 | 95 | 100% (1 h) |
| 10d | t-butanol (350 mL) | 30 mL | 30 mL | 45g/150 mL | 0.15 | 95 | 100% (1.5 h) |
a
Charged with compound 4 (5 g); the pH (6.8–7.2) was adjusted with sodium hydroxide solution (1 mol/L), 30 °C.
b
The concentration of cells was about 400 g/L.
c
Determined by HPLC.
d
Charged with compound 4 (50 g).