培养基成分对植物乳杆菌LIP-1抗冷冻性的影响

以益生菌植物乳杆菌LIP-1为研究对象，MRS基础培养基为对照，通过改变培养基的成分及其含量（碳源、氮源、碳氮总量及碳氮比、缓冲盐），研究培养基成分的变化对植物乳杆菌LIP-1高密度培养的活菌数以及冷冻干燥后存活率的影响。结果表明：通过优化工艺和配方确定的最佳培养基组成为碳源（蔗糖）添加量33.35 g/L、复合氮源（酵母粉、大豆蛋白胨、酪蛋白胨质量比3∶3∶5）添加量10.80 g/L、缓冲盐（乙酸钠、磷酸氢二钾、柠檬酸钠质量比2.5∶1∶1）添加量14.85 g/L（即0.13 mol/L）；用优化后

Cryoprotective Effect of Medium Components on Lactobacillus plantarum LIP-1

The probiotic Lactobacillus plantarum LIP-1 was cultured in modified MRS medium at high cell density to investigate the effect of changes in medium components (the types and amounts of nitrogen source, carbon source and buffer salt, total amount of carbon and nitrogen, and carbon/nitrogen ratio) on the viable cell count and survival rate after freezedrying of this strain. The optimal medium was found to be composed of carbon source (sucrose) 33.35 g/L, nitrogen source (yeast powder, soy peptone and casein peptone, 3:3:5, m/m) 10.80 g/L, and buffer salt (sodium acetate, potassium dihydrogen phosphate and sodium citrate, 2.5:1:1, m/m) 14.85 g/L (namely 0.13 mol/L). The viable cell count of strain LIP-1 cultured in the optimized medium after freeze-drying was 9.767 (lg(CFU/mL)), which was distinctly higher than that cultured in MRS medium. The modified medium allowed high-cell-density fermentation of Lactobacillus plantarum LIP-1 while maintaining its viability during freeze-drying.