Table 1 Physical and coded values of the variables used in the central composite design
Coded symbol | Variables | Values of coded levels | ||||
|---|---|---|---|---|---|---|
(-1.28) | (-1) | (0) | (+1) | (+1.28) | ||
X1 | Operating temperature (°C) | 23.28 | 25 | 31 | 37 | 38.72 |
X 2 | Initial value of fermentation pH | 4.56 | 4.8 | 5.65 | 6.5 | 6.74 |
X3 | Glucose addition (g/L) | 3.56 | 5 | 10 | 15 | 16.44 |