Table 3. Variables and their effects values from a quadratic regression equation results of Plackett-Burman design
Variable (Xi) | Effect(Exi) | Coefficient(βi) | Sum of squares | F-value | p-value | Confidence level (%) |
Glucose | -4.35 | -2.17 | 94.55 | 15.11 | 0.0081 | 99.20 |
Sucrose | 3.54 | 1.77 | 62.68 | 10.01 | 0.0195 | 98.05 |
Fructose | -2.55 | -1.28 | 32.51 | 5.19 | 0.0629 | 93.71 |
GOS1) | 1.7552 | 0.88 | 15.41 | 2.46 | 0.1677 | 83.23 |
Molasses | 11.99 | 6.00 | 719.52 | 114.95 | <0.0001 | 99.99 |
Yeast extract | -3.02 | -1.51 | 45.48 | 7.27 | 0.0358 | 96.42 |
Beef extract | 0.72 | 0.36 | 2.62 | 0.42 | 0.5415 | 45.85 |
Tryptone | 1.02 | 0.51 | 5.17 | 0.83 | 0.3983 | 60.17 |
Peptone | 2.27 | 1.14 | 25.86 | 4.13 | 0.0884 | 91.16 |
NaCl | 0.99 | 0.49 | 4.89 | 0.78 | 0.4109 | 58.91 |
KH2PO4 | -1.39 | -0.69 | 9.61 | 1.54 | 0.2615 | 73.85 |
K2HPO4 | 0.79 | 0.40 | 3.16 | 0.51 | 0.5039 | 49.61 |
MgSO4 | 0.86 | 0.43 | 3.68 | 0.59 | 0.4726 | 52.74 |
KCl | 1.38 | 0.69 | 9.49 | 1.52 | 0.2642 | 73.58 |
1) GOS, galacto-oligosaccharide.