培养基成分对植物乳杆菌LIP-1抗冷冻性的影响

Cryoprotective Effect of Medium Components on Lactobacillus plantarum LIP-1

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);用优化后的培养基培养的菌株在冻干后的活菌数可达9.767 (lg(CFU/mL)),显著高于MRS基础培养基。通过改变培养基成分可以在保证植物乳杆菌LIP-1高密度发酵的同时提高其抗冷冻干燥性能。

The probiotic Lactobacillus plantarum LIP-1was cultured in modified MRS medium at high cell density toinvestigate the effect of changes in medium components(the types and amounts of nitrogen source,carbon source and buffersalt,total amount of carbon and nitrogen,and carbon/nitrogen ratio)on the viable cell count and survival rate after freezedryingof this strain.The optimal medium was found to be composed of carbon source(sucrose)33.35g/L,nitrogen source(yeast powder,soy peptone and casein peptone,3:3:5,m/m)10.80g/L,and buffer salt(sodium acetate,potassium dihydrogenphosphate and sodium citrate,2.5:1:1,m/m)14.85g/L(namely0.13mol/L).The viable cell count of strain LIP-1cultured inthe optimized medium after freeze-drying was9.767(lg(CFU/mL)),which was distinctly higher than that cultured in MRSmedium.The modified medium allowed high-cell-density fermentation of Lactobacillus plantarum LIP-1while maintainingits viability during freeze-drying.