Table 7 Experimental design and results of box–behnken optimization experiment
Trials | A (inoculum size) | B (NH4)2HPO4 | C (Initial pH) | PHB (g/L) | |||
|---|---|---|---|---|---|---|---|
| Â | Coded level | Real level (%) | Coded level | Observed | Coded level | Real level ( o c) | Observed |
1 | 1 | 6 | 0 | 1.5 | −1 | 6.5 | 5.25 |
2 | −1 | 2 | −1 | 2 | 0 | 7 | 5.41 |
3 | 0 | 4 | 1 | 2 | 1 | 7.5 | 4.48 |
4 | −1 | 2 | 0 | 1.5 | −1 | 6.5 | 4.45 |
5 | 1 | 6 | 1 | 2 | 0 | 7 | 5.284 |
6 | 0 | 4 | 1 | 2 | −1 | 6.5 | 3.97 |
7 | −1 | 2 | 0 | 1.5 | 1 | 7.5 | 5.369 |
8 | 0 | 4 | −1 | 2 | 1 | 7.5 | 3.87 |
9 | 0 | 4 | −1 | 2 | −1 | 6.5 | 4.4 |
10 | −1 | 2 | 1 | 2 | 0 | 7 | 4.805 |
11 | 0 | 4 | 0 | 1.5 | 0 | 7 | 4.32 |
12 | 0 | 4 | 0 | 1.5 | 0 | 7 | 4.35 |
13 | 0 | 4 | 0 | 1.5 | 0 | 7 | 5.02 |
14 | 0 | 4 | 0 | 1.5 | 0 | 7 | 4 |
15 | 1 | 6 | 0 | 1.5 | 1 | 7.5 | 4.92 |
16 | 1 | 6 | 0 | 2 | −1 | 7 | 4.62 |
17 | −1 | 4 | −1 | 1.5 | 0 | 7 | 5.72 |