Table 3.
Results of analysis of variance (ANOVA) for response surface quadratic model obtained from experimental design (for media components and process parameters)
| Source of variation | Sum of squares | Degree of freedom | Mean square | F value | Probability > F |
|---|---|---|---|---|---|
| Media components | |||||
| Model | 2755.41 | 9 | 306.16 | 331.48 | <0.0001 |
| X—C-conc. | 68.43 | 1 | 68.43 | 74.09 | 0.0003 |
| Y—N-conc. | 10.60 | 1 | 10.60 | 11.47 | 0.0195 |
| Z—pH | 6.92 | 1 | 6.92 | 7.50 | 0.0409 |
| XY | 70.53 | 1 | 70.53 | 76.37 | 0.0003 |
| XZ | 382.11 | 1 | 383.11 | 413.71 | <0.0001 |
| YZ | 76.25 | 1 | 76.25 | 82.56 | 0.0003 |
| X 2 | 1.32 | 1 | 1.32 | 1.42 | 0.2862 |
| Y 2 | 1.54 | 1 | 1.54 | 1.67 | 0.2532 |
| Z 2 | 1612.42 | 1 | 1612.42 | 1745.76 | < 0.0001 |
| Residual | 4.62 | 5 | 0.92 | ||
| Lack of fit | 2.78 | 1 | 2.78 | 6.06 | 0.0695 |
| Pure error | 1.84 | 4 | 0.46 | ||
| Core total | 2760.3 | 14 | |||
| Process parameters | |||||
| Model | 2212.05 | 9 | 245.78 | 323.30 | < 0.0001 |
| A—temperature | 426.44 | 1 | 426.44 | 560.93 | < 0.0001 |
| B—incubation time | 1.93 | 1 | 1.93 | 2.53 | 0.1723 |
| C—inoculum size | 18.08 | 1 | 18.08 | 23.78 | 0.0046 |
| AB | 70.15 | 1 | 70.15 | 92.27 | 0.0002 |
| AC | 30.57 | 1 | 30.57 | 40.21 | 0.0014 |
| BC | 73.59 | 1 | 73.59 | 96.80 | 0.0002 |
| AC | 30.57 | 1 | 30.57 | 40.21 | 0.0014 |
| BC | 73.59 | 1 | 73.59 | 96.80 | 0.0002 |
| A 2 | 437.32 | 1 | 437.32 | 575.25 | < 0.0001 |
| B 2 | 78.33 | 1 | 78.33 | 103.03 | 0.0002 |
| C 2 | 109.03 | 1 | 109.03 | 143.42 | < 0.0001 |
| Residual | 3.80 | 5 | 0.76 | ||
| Lack of fit | 2.44 | 1 | 2.44 | 7.20 | 0.0551 |
| Pure error | 1.36 | 4 | 0.34 | ||
| Cor total | 2215.85 | 14 | |||