Table 4. Central composite design (CCD) and experimental results
| Factor | Symbol (unit) | Code values |
| -2 | -1 | 0 | +1 | +2 |
| Molasses | X1 (g/L) | 1.0 | 3.0 | 5.0 | 7.0 | 9.0 |
| Sucrose | X2 (g/L) | 1.0 | 3.0 | 5.0 | 7.0 | 9.0 |
| Peptone | X3 (g/L) | 0.5 | 2.0 | 3.5 | 5.0 | 6.5 |
|
| Runs | X1 | X2 | X3 | Y1), DCW (g/L) |
| 1 | -1 | +1 | +1 | 11.443 |
| 2 | +1 | -1 | -1 | 14.737 |
| 3 | +1 | +1 | -1 | 23.667 |
| 4 | 0 | 0 | 0 | 12.067 |
| 5 | +1 | -1 | +1 | 16.267 |
| 6 | -1 | -1 | -1 | 7.44 |
| 7 | -2 | 0 | 0 | 11.807 |
| 8 | 0 | 0 | -2 | 9.813 |
| 9 | -1 | -1 | +1 | 11.533 |
| 10 | +1 | +1 | +1 | 21.087 |
| 11 | +2 | 0 | 0 | 25.020 |
| 12 | -1 | +1 | -1 | 8.537 |
| 13 | 0 | -2 | 0 | 9.350 |
| 14 | 0 | 0 | 0 | 11.890 |
| 15 | 0 | 0 | +2 | 14.470 |
| 16 | 0 | +2 | 0 | 15.703 |
All experiments were performed in triplicate.
1) Y, response value, dry cell weight of B. subtilis SRCM102046.