Table 3.
RSM design matrix with real/coded values and experimental results.
| Run | Dependent variables | D(-) lactic acid | Productivity | Y p/s | Residual sucrose | ||
|---|---|---|---|---|---|---|---|
| X 1 | X 2 | X 3 | g/L | g/L·h | g/g | g/L | |
| 1 | 100.00 (-1) | 35.00 (-1) | 2.20 (-1) | 82.30 | 1.71 | 0.86 | 21.66 |
| 2 | 200.0/0 (1) | 35.00 (-1) | 2.20 (-1) | 82.61 | 1.72 | 0.73 | 107.22 |
| 3 | 100.00 (-1) | 95.00 (1) | 2.20 (-1) | 79.53 | 1.66 | 0.95 | 32.40 |
| 4 | 200.00 (1) | 95.00 (1) | 2.20 (-1) | 82.99 | 1.73 | 0.98 | 130.36 |
| 5 | 100.00 (-1) | 35.00 (-1) | 7.80 (1) | 88.00 | 1.83 | 0.98 | 25.44 |
| 6 | 200.00 (1) | 35.00 (-1) | 7.80 (1) | 85.35 | 1.78 | 0.91 | 122.48 |
| 7 | 100.00 (-1) | 95.00 (1) | 7.80 (1) | 88.85 | 1.85 | 0.94 | 21.26 |
| 8 | 200.00 (1) | 95.00 (1) | 7.80 (1) | 80.93 | 1.69 | 0.93 | 128.96 |
| 9 | 150.00 (0) | 65.00 (0) | 0.13 (-1.68) | 102.03 | 2.13 | 0.97 | 60.27 |
| 10 | 150.00 (0) | 65.00 (0) | 9.87 (+1.68) | 110.21 | 2.30 | 0.99 | 53.55 |
| 11 | 150.00 (0) | 14.60 (-1.68) | 5.00 (0) | 82.39 | 1.72 | 0.97 | 80.36 |
| 12 | 150.00 (0) | 115.40 (+1.68) | 5.00 (0) | 102.77 | 2.14 | 0.98 | 60.77 |
| 13 | 66.00 (-1.68) | 65.00 (0) | 5.00 (0) | 68.88 | 1.44 | 0.97 | 10.61 |
| 14 | 234.00 (+1.68) | 65.00 (0) | 5.00 (0) | 75.02 | 1.56 | 0.49 | 111.38 |
| 15 | 150.00 (0) | 65.00 (0) | 5.00 (0) | 124.56 | 2.60 | 0.96 | 36.30 |
| 16 | 150.00 (0) | 65.00 (0) | 5.00 (0) | 118.75 | 2.47 | 0.94 | 39.28 |
| 17 | 150.00 (0) | 65.00 (0) | 5.00 (0) | 122.56 | 2.55 | 0.96 | 37.79 |
X 1 = sugar molasses (g/L of sucrose), X2 = corn steep liquor (mL/L), X3 = salt solution (mL/L), and Yp/s = yield. Culture conditions: initial pH at 7.0, 5% of CaCO3 used as pH neutralizer, 50 mL of work volume, 10% inoculum (v/v), and 35°C. Fermentation was carried under stationary condition for 48 hours. Coded values were present in parenthesis.