Table 6 Real–coded values of independent variables and regression analysis for PGase optimization by Box-Behnken
Variable | Low level | Middle level | High level | Model term | Main effect | Β- coefficient | t-value | P-value | % confidence |
|---|---|---|---|---|---|---|---|---|---|
-1 | 0 | +1 | |||||||
Orange peel waste (w/v %) | 0.5 | 1.5 | 2.5 | X1 | 0.135 | 0.0675 | 0.92151 | 0.399067 | 60.10 |
pH | 6.0 | 8.0 | 10.0 | X7 | 0.3306 | 0.16525 | 2.255994 | 0.073721 | 92.63 |
Incubation temp. °C | 30.0 | 40.0 | 50.0 | X9 | -0.832 | -0.416 | -5.67923 | 0.002357* | 99.76 |
X12 | -0.325 | -0.16225 | -1.50482 | 0.192706 | 80.73 | ||||
X72 | -1.805 | -0.90275 | -8.37274 | 0.000398* | 99.96 | ||||
X93 | -2.044 | -1.02275 | -9.48571 | 0.00022* | 99.99 | ||||
X1.X7 | -1.15 | -0.575 | -5.55072 | 0.002608* | 99.73 | ||||
X1.X9 | -0.19 | -0.095 | -0.91708 | 0.401174 | 60.00 | ||||
X7.X9 | 0.044 | 0.022 | 0.212375 | 0.840201 | 16.00 |