Table 1 Levels of the factors tested in the Plackett-Burman design
Factor | Code level | ||
|---|---|---|---|
−1 | 0 | +1 | |
A-Dextrose (g/l) | 20 | 25 | 30 |
B-Peptone (g/l) | 5 | 7.5 | 10 |
C-Initial pH | 5 | 7 | 9 |
D-Temperature (°C) | 25 | 30 | 35 |
E-NaCl (g/l) | 1 | 3 | 5 |
F-Fermentation time (days) | 10 | 12.5 | 15 |
G- MgSO4.7H2O (g/l) | 0.1 | 0.3 | 0.5 |