TABLE 2.
Enzymatic activities of C. butyricum VPI 3266 and C. acetobutylicum DG1(pSPD5) in chemostat cultures (0.05 h−1, 650 mM glycerol, pH 6.5, 35°C)
| Enzyme type | Enzymea | Activity (U/mg protein [SD])b
|
|
|---|---|---|---|
| C. butyricum VPI 3266 | C. acetobutylicum DG1 (pSPD5) | ||
| Hydrogenase and coupling enzymes | Hydrogenase (H2 evolution) | 0.045 (0.03) | 0.43 (0.05) |
| Fd-NAD+ reductase | 0.03 (0.01) | 0.25 (0.08) | |
| NADH-Fd reductase | 0.33 (0.005) | 0.034 (0.01) | |
| Glycerol oxidation enzymes | Glycerol dehydrogenase | 0.26 (0.05) | <0.005 |
| DHA kinase | 1.1 (0.1) | <0.002 | |
| Glycerol kinase | <0.002 | 0.14 (0.03) | |
| Glycerol 3-P dehydrogenase | <0.002 | 0.52 (0.05) | |
| Glycerol reduction enzymes | 1,3-Pdiol dehydrogenase | 0.37 (0.05) | 1.2 (0.2) |
| Glycerol dehydratase | 0.42 (0.15) | 1.7 (0.4) | |
| Acidogenic enzymes | Phosphotransacetylase | 0.30 (0.03) | 0.25 (0.03) |
| Acetate kinase | 0.56 (0.03) | 0.32 (0.04) | |
| Phosphotransbutyrylase | 8.04 (0.53) | 6.95 (0.35) | |
| Butyrate kinase | 1.26 (0.20) | 1.46 (0.18) | |
| Lactate dehydrogenase | <0.002 | 0.19 (0.01) | |
| Central axis enzymes | Pyruvate-Fd oxidoreductase | 4.0 (0.8) | 4.5 (0.2) |
| Pyruvate formate lyase | 0.15 (0.03) | 0.12 (0.02) | |
| Glyceraldehyde 3-P dehydrogenase | 5.58 (0.88) | 4.96 (0.05) | |
a
Fd, ferredoxin; DHA, dihydroxyacetone; 1,3-Pdiol, 1,3-propanediol.
b
Data in parentheses are standard deviation values from four to six determinations.