Study on the Optimization of Enrichment Medium of Lactobacillus casei Zhang

Abstract:

The effects of different carbon source, nitrogen source, proportion of carbon and nitrogen source, microelement and buffer salts on the growth of Lactobacillus casei Zhang isolated from Koumiss were studied. The enrichment medium for Lactobacillus casei Zhang was optimized by response surface methodology and its composition was glucose 20.9 g/L, soy peptone 10.45 g/L, yeast extract 10.45 g/L, K2HPO4 3.5 g/L, sodium acetate 14.6 g/L, sodium citrate 2.35 g/L, MgSO4?7H2O 1.0 g/L, MnSO4?5H2O 54 mg/L, CuSO4?5H2O 10 mg/L, tween 80 1.0 g/L. After cultivated in enrichment medium for 18h at 37℃, the living cells of Lactobacillus casei Zhang were 4.78×109 CFU/mL, which was about 10 times higher than in MRS (4.8×108 CFU/mL).

Key words:Lactobacillus casei, Nutrients, Enrichment medium, Optimization