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Table I.
Factors and levels of the variables in coded units for RSM study.
| Factors | Levels | ||||
|---|---|---|---|---|---|
| Code | −1.682 | −1 | 0 | +1 | +1.682 |
| Temperature (X 1; °C) | 13.2 | 20 | 30 | 40 | 46.8 |
| Substrate concentration (X 2; %) | 29.8 | 38 | 50 | 62 | 70.2 |
| Reaction time (X 3; h) | 1.3 | 3 | 5.5 | 8 | 9.7 |