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

Table 7

Comparison experiments using optimized skim milk and yeast extract based on biomass production, β-galactosidase production, lactose, and free amino nitrogen residual at 21 h of cultivation period.

Skim milk (% wt/vol)*	Biomass production (log10 cfu/mL)	β-Galactosidase production (U/mL)	Lactose (g/L)	Free amino nitrogen (mg/L)
0	1.03±0.11^a∗∗	0.35±0.21^a	0.00±0.00^a	141.57±18.90^a
4	7.19±0.07^b	6.36±0.16^b	7.25±2.02^b	153.80±15.46^a
7.17 (optimized concentrations)	7.35±0.06^b	6.34±0.08^b	15.92±3.23^c	198.73±13.67^a
10	7.78±0.55^b	5.54±1.02^b	21.39±3.29^c	251.57±18.71^b
12	7.52±0.63^b	5.23±0.56^b	25.98±3.19^c	282.27±11.13^b
TPY	7.79±0.45^b	0.05±0.11^a	0.00±0.00^a	374.20±16.22^c

∗Cultivation was conducted in different concentrations of skim milk with 1.02% yeast extract supplementation.
**Values in the same column with different letters were significantly different (𝑃<0.05).