Table 4. Factors and factor interactions used to predict the accumulation of PSL.
| Factor | F-value | p-value |
|---|---|---|
| Model | 24.06 | <0.0001 |
| A (temperature) | 30.61 | <0.0001 |
| B (incubation time) | 7.25 | 0.0130 |
| C (inoculum density) | 23.93 | <0.0001 |
| D (light) | 73.87 | <0.0001 |
| AB | 23.56 | <0.0001 |
| AC | 4.39 | 0.0473 |
| AD | 25.68 | <0.0001 |
| BC | 6.74 | 0.0161 |
| BD | 5.59 | 0.0268 |
A reduced two-factor interaction model was used to analyze the data. Factors showing a significant influence on the amount of PSL were preselected by automated backward selection with a p-value threshold of 0.100. Factors with a p-value > 0.05 were removed manually, except those needed to maintain the model hierarchy. A p-value of 0.05 indicates a significance (alpha) level of 5%.