Table 2.
Values of CA levels detected by HPLC based on the central composite design (CCD) matrix of the studied variables (glucose and TCP) on the PNR-based medium fermented by Trichoderma sp. WKA55.
| Run | Input variables | Output variable | |||
|---|---|---|---|---|---|
| Coded unit | Actual unit (mg/g PNR) | Citric acid (μg/g PNR ± SD) | |||
| Glucose | TCP | Glucose | TCP | ||
| 1 | −1 | −1 | 10 | 10 | 885.5 ± 3.5 |
| 2 | −1 | 1 | 10 | 20 | 966.9 ± 6.4 |
| 3 | 1 | −1 | 20 | 10 | 1478.4 ± 28.0 |
| 4 | 1 | 1 | 20 | 20 | 2887.5 ± 14.4 |
| 5 | 0 | −1.414 | 15 | 7.929 | 1322.2 ± 23.1 |
| 6 | 0 | 1.414 | 15 | 22.071 | 2159.3 ± 20.8 |
| 7 | −1.414 | 0 | 7.929 | 15 | 1587.3 ± 11.6 |
| 8 | 1.414 | 0 | 22.071 | 15 | 2413.4 ± 8.1 |
| 9* | 0 | 0 | 15 | 15 | 5555.7 ± 12.1 |
| 10* | 0 | 0 | 15 | 15 | 5357.1 ± 11.7 |
| 11* | 0 | 0 | 15 | 15 | 5459.3 ± 11.6 |
*
The middle concentrations.