Table 2.
Central composite design along with observed and predicted results for ethanol production
| Run | A. Fermentation time (h) | B. Fermentation pH | C. Saccharomyces:Zymomonas | Ethanol yield (mg/ml) | |
|---|---|---|---|---|---|
| Observed response | Predicted response | ||||
| 1 | 0 (36) | 1.68 (8.68) | 0 (1) | 11.6 | 10.5 |
| 2 | 1 (42) | −1 (5) | −1 (0.5) | 5.8 | 6.1 |
| 3 | 0 (36) | 0 (6) | 0 (1) | 13.6 | 13.0 |
| 4 | 0 (36) | 0 (6) | 1.68 (0.8) | 8.5 | 7.9 |
| 5 | 0 (36) | 0 (6) | 0 (1) | 12.9 | 13.0 |
| 6 | 0 (36) | −1.68 (3.32) | 0 (1) | 5.6 | 5.7 |
| 7 | 1 (42) | −1 (5) | 1 (1.5) | 7.3 | 7.1 |
| 8 | 1 (42) | 1 (7) | −1 (0.5) | 8.9 | 9.1 |
| 9 | −1.68 (26.4) | 0 (6) | 0 (1) | 3.7 | 3.1 |
| 10 | −1 (30) | −1 (5) | −1 (0.5) | 2.6 | 2.3 |
| 11 | −1 (30) | 1 (7) | 1 (1.5) | 6.9 | 7.3 |
| 12 | 0 (36) | 0 (6) | 0 (1) | 12.8 | 13.0 |
| 13 | −1 (30) | 1 (7) | −1 (0.5) | 4.4 | 5.3 |
| 14 | 0 (36) | 0 (6) | 0 (1) | 13.2 | 13.0 |
| 15 | 0 (36) | 0 (6) | −1.68 (0.7) | 5.7 | 5.8 |
| 16 | −1 (30) | −1 (5) | 1 (1.5) | 4.1 | 4.6 |
| 17 | 0 (36) | 0 (6) | 0 (1) | 12.3 | 13.0 |
| 18 | 1.68 (45.6) | 0 (6) | 0 (1) | 8.7 | 8.3 |
| 19 | 0 (36) | 0 (6) | 0 (1) | 13.0 | 13.0 |
| 20 | 1 (42) | 1 (7) | 1 (1.5) | 8.8 | 9.8 |