| 因素 Factors | 编码 Codes | 水平 Levels | ||
| −1 | 0 | 1 | ||
| 酶底物浓度/% Enzyme substrate content/% | X1 | 0.60 | 0.70 | 0.80 |
| 温度(℃) Temperature/˚C | X2 | 55 | 60 | 65 |
| 时间/h Time/h | X3 | 2.5 | 3.0 | 3.5 |