Table 2.

Analysis of the significance of PB design.

Source	Sum of squares	df	Mean square	F-value	p-value
X1 (beef broth)	0.0444	1	0.0444	17.47	0.0087**
X2 (peptone)	0.1027	1	0.1027	40.4	0.0014**
X3 (yeast extract)	0.0024	1	0.0024	0.9475	0.3751
X4 (glucose)	0.0784	1	0.0784	30.85	0.0026**
X5 (KH₂PO4)	0.0001	1	0.0001	0.0295	0.8703
X6 (MgSO4)	0.003	1	0.003	1.18	0.3263

ANOVA using design-expert 11.0. **significant at p < 0.01.