Table 5. Effects of various medium constituents on biomass production from the results of Plackett-Burman design

Variable(Xi)	Effect(Exi)	Coefficient(βi)	Sum of squares	F-value	p-value	Confidence level (%)
Model		6.61	392.47	50.33	0.0002	99.98
Glucose	-0.30	-0.15	0.46	0.89	0.3891	61.09
Sucrose	0.20	0.099	0.20	0.38	0.5660	43.40
Maltose	0.65	0.33	2.14	4.11	0.0983	90.17
Lactose	0.18	0.092	0.17	0.33	0.5930	40.70
Fructose	6.71E-004	3.355E-004	2.251E-006	4.33E-006	0.9984	0.16
Molasses	8.78	4.39	385.73	741.98	< 0.0001	99.99
GOS	-0.25	-0.12	0.30	0.58	0.4811	51.89
Yeast extract	0.44	0.22	0.96	1.85	0.2324	76.76
Tryptone	-0.12	-0.058	0.067	0.13	0.7337	26.63
Peptone	-0.42	-0.21	0.88	1.69	0.2508	74.92
Dipotassium phosphate	0.28	0.14	0.38	0.73	0.4311	56.89
Potassium phospate	-0.46	-0.23	1.05	2.03	0.2136	78.64
Ammonium citrate	-0.073	-0.036	0.026	0.051	0.8306	16.94
Magnesium sulfate	-0.012	-0.062	0.077	0.15	0.7164	28.36
Manganese sulfate	-0.079	-0.039	0.031	0.060	0.8169	18.31
Standard deviation	0.69		Press1)		63.05
Mean	6.57		R - square		0.9927
Coefficient of variation	10.57		Adjusted R - square		0.9743

¹⁾The predicted residual sum of squares for the model.