Lactobacillus reuteri IMAU10240增殖培养基及高密度培养工艺优化

Lactobacillus reuteri IMAU10240(L.reuteri IMAU10240)是一株具有潜在益生特性的乳酸菌,为实现产业化应用,对其培养工艺进行优化以提高其活菌数。本研究以MRS培养基为基础,通过单因素筛选试验、正交试验和响应面优化试验对该菌株的培养基以及培养条件进行优化。通过实验确定L.reuteri IMAU10240最适培养基:蔗糖100.00 g/L,大豆蛋白胨13.25 g/L,酵母粉8.84 g/L,酵母蛋白胨13.25 g/L,Na_2HPO_4 19.85 g/L,柠檬酸2.58 g/L,MnSO_4·5H_2O 0.12 g/L,MgSO_4·7H_2O 0.40 g/L,甘油2.76 g/L,吐温-80 1.00 g/L,L-半胱氨酸盐酸盐0.50 g/L。初始pH 6.5,通入氮气37℃恒pH 5.5培养7~8 h。利用优化好的配方工艺进行5 L/50 L/200 L发酵罐的小试及中试试验,验证L.reuteri IMAU10240的发酵工艺,活菌数为7.57×10~9 CFU/mL,冻干菌粉活菌数为2.59×10~(11) CFU/g,可以进行生产验证。

Optimization of Enrichment Medium and High Cell Density Cultivation of Lactobacillus reuteri IMAU10240

Lactobacillus reuteri IMAU10240 is a potential probiotic lactic acid bacterium (LAB). This study aimed to achieve high viable counts of L. reuteri IMAU10240 by optimization of the composition of deMan Rogosa Sharpe (MRS) medium and culture conditions for industrialization application of this strain. The optimization was done using one-factor-at-a-time method, orthogonal array design and response surface methodology. The optimal medium composition was determined as follows (g/L): sucrose 100.00, soy peptone 13.25, yeast extract powder 8.84, yeast peptone 13.25, Na2HPO4 19.85, citric acid 2.58, MgSO4·7H2O 0.40, MnSO4·5H2O 0.12, glycerol 2.76, Tween-80 1.00, and L-cysteine hydrochloride 0.50, and the optimal culture conditions were 7–8 h culture at 37 ℃ and constant pH 5.5 under nitrogen atmosphere. In small-scale and pilot-scale experiments, the optimized conditions yielded a viable cell count of 7.57 × 109 CFU/mL, which increased to 2.59 × 1011 CFU/g after lyophilization. The enrichment medium and culture conditions can?be further verified in industrial production.