Table 1 Experimental range and levels of the independent variables for the CCD based RSM experiment
Variable | Components | Range | Levels of variable studied | ||
|---|---|---|---|---|---|
Low (− 1) | Centre point (0) | High (+ 1) | |||
A | Wheat bran | 0.5–1.5 | 0.5 | 1 | 1.5 |
B | Magnesium sulphate | 0.3–0.7 | 0.3 | 0.5 | 0.7 |
C | Calcium chloride | 0.5–1.0 | 0.5 | 0.7 | 1 |
D | Temperature | 25–45 | 25 | 35 | 45 |
E | pH | 3.0–7.0 | 3 | 5 | 7 |