Optimization of Milk-Based Medium for Efficient Cultivation of Bifidobacterium pseudocatenulatum G4 Using Face-Centered Central Composite-Response Surface Methodology

Table 6

ANOVA and regression analysis for the response of biomass production (𝑦₁): optimization of skim milk (% wt/vol) and yeast extract (% wt/vol).

Source of variation	Sum of squire or coefficient estimate	DF^a	MS or Std error	𝐹 value	𝑃 value
Model^b	8.95	4	2.24	2893.35	<0.001
Residual	6.186𝐸−003	8	7.732𝐸−004
Lack of fit	4.466𝐸−003	4	1.116𝐸−003	2.60	0.1890
Pure error	1.720𝐸−003	4	4.300𝐸−004
Total	8.95	12
Factor^c
Intercept	7.14	1
𝑥1	1.01	1	0.011	7889.68	<0.001^d
𝑥2	−6.667𝐸−003	1	0.011	0.34	0.5732
𝑥1^2	−0.94	1	0.015	3667.73	<0.001^d
𝑥1𝑥2	−0.055	1	0.014	15.65	0.0042^d

aDF: degree of freedom.
^b𝑅² = 99.93%.
^c𝑥₁, skim milk (% wt/vol), 𝑥₂, yeast extract (% wt/vol).
^dSignificant at 𝛼=0.05.