Table 1 Actual levels for the four variables Box-Behnken design
Independent variables | Symbols | Coded and actual levels | ||
|---|---|---|---|---|
− 1(low) | 0 | + 1(high) | ||
Incubation time (h) | A | 12 | 42 | 72 |
pH | B | 5.5 | 8.0 | 10.5 |
Substrate conc (mM) | C | 0.030 | 0.115 | 0.200 |
Temperature (°C) | D | 30 | 37.5 | 45 |