Table 1 Actual and coded level of variables tested with Plakett-Burman design
Code | −1 | 1 | |
|---|---|---|---|
Urea | X1 | 0.1 | 5 |
MgSO4 | X2 | 0.1 | 3 |
CaCl2 | X3 | 0.1 | 3 |
pH | X4 | 3 | 8 |
Ammonium sulfate | X5 | 1 | 10 |
Fermentation time | X6 | 48 | 216 |
Protease peptone | X7 | 1 | 5 |
Yeast extract | X8 | 1 | 5 |
KH2PO4 | X9 | 0.1 | 3 |
Moisture ratio | X10 | 1:1 | 1:3 |