Table 2.
Plackett-Burman experimental design matrix with proteolytic enzymes production levels.
| Variables | T | HGW | SP | KH2PO4 | MgSO4 | NaCl | pH | ZnCl2 | Na2HPO4 | CaCl2 | IS | Protease activity |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Run | Units | |||||||||||
| °C | g/L | g/L | g/L | g/L | g/L | — | g/L | g/L | g/L | Sp/mL | U/mL | |
|
| ||||||||||||
| (1) | 30 | 5 | 5 | 1 | 0.5 | 0.3 | 8 | 0.1 | 1.6 | 0.4 | 107 | 74.11 |
| (2) | 30 | 15 | 2 | 2 | 0.5 | 0.3 | 5 | 0.2 | 1.6 | 0.8 | 5 × 106 | 60.58 |
| (3) | 25 | 15 | 5 | 1 | 1 | 0.3 | 5 | 0.1 | 1.6 | 0.8 | 107 | 68.62 |
| (4) | 30 | 5 | 5 | 2 | 0.5 | 0.6 | 5 | 0.1 | 0.8 | 0.8 | 107 | 78.82 |
| (5) | 30 | 15 | 2 | 2 | 1 | 0.3 | 8 | 0.1 | 0.8 | 0.4 | 107 | 85.49 |
| (6) | 30 | 15 | 5 | 1 | 1 | 0.6 | 5 | 0.2 | 0.8 | 0.4 | 5 × 106 | 14.11 |
| (7) | 25 | 15 | 5 | 2 | 0.5 | 0.6 | 8 | 0.1 | 1.6 | 0.4 | 5 × 106 | 183.13 |
| (8) | 25 | 5 | 5 | 2 | 1 | 0.3 | 8 | 0.2 | 0.8 | 0.8 | 5 × 106 | 128.43 |
| (9) | 25 | 5 | 2 | 2 | 1 | 0.6 | 5 | 0.2 | 1.6 | 0.4 | 107 | 74.11 |
| (10) | 30 | 5 | 2 | 1 | 1 | 0.6 | 8 | 0.1 | 1.6 | 0.8 | 5 × 106 | 52.94 |
| (11) | 25 | 15 | 2 | 1 | 0.5 | 0.6 | 8 | 0.2 | 0.8 | 0.8 | 107 | 55.29 |
| (12) | 25 | 5 | 2 | 1 | 0.5 | 0.3 | 5 | 0.1 | 0.8 | 0.4 | 5 × 106 | 96.86 |
T: temperature; HGW: hulled grain of wheat; SP: shrimp peptone; IS: Inoculum's size; Sp: spores.