Table 7.
Levels of the variables and statistical analysis in PB for yield of 3-Met.
| Code | Variable | Low Level (−1) | High Level (+1) | Effect (EXi) | F Values | p Values | Rank | Significance |
|---|---|---|---|---|---|---|---|---|
| X1 | Glucose concentration (g/L) | 50 | 70 | −0.0491 | 0.45 | 0.532 | 6 | - |
| X2 | Yeast extract concentration (g/L) | 0.1 | 0.7 | 0.4859 | 44.1 | 0.001 | 1 | *** |
| X3 | L-Met concentration (g/L) | 0 | 4 | 0.3081 | 17.72 | 0.008 | 2 | ** |
| X4 | Temperature (°C) | 24 | 28 | 0.0159 | 0.05 | 0.837 | 8 | - |
| X5 | Initial pH | 3 | 5 | −0.0146 | 0.04 | 0.849 | 9 | - |
| X6 | Incubation time (h) | 24 | 48 | 0.1922 | 6.9 | 0.047 | 3 | * |
| X7 | Shaking speed (rpm) | 100 | 200 | 0.0203 | 0.08 | 0.792 | 7 | - |
| X8 | Loading volume (mL/250 mL) | 25 | 75 | −0.1256 | 2.95 | 0.147 | 5 | - |
| X9 | Inoculum size (%) | 0.8 | 3.2 | 0.1436 | 3.85 | 0.107 | 4 | - |
| model | 8.46 | 0.015 | * | |||||
| R2 = 0.9384 | R2Adj = 0.8274 | |||||||
Note: “-” Not significant (p > 0.05); “*” Significant at 5% level (p < 0.05); “**” Significant at 1% level (p < 0.01); “***” Significant at 0.1% level (p < 0.001).