响应面法优化嗜热链球菌增殖培养基

Optimization of Streptococcus thermophilus proliferation medium by response surface methodology

目的为了降低嗜热链球菌工业化生产成本,提高其发酵活菌数,对嗜热链球菌原始培养基的成分进行了响应面优化。方法利用Design-Expert软件首先采用Plackett-Burman试验设计筛选出了影响嗜热链球菌生长的显著因子,再依据响应面法设计试验,得到嗜热链球菌的优化培养基配比。结果乳糖、酵母粉和L-半胱氨酸为嗜热链球菌生长的显著性因子;优化后培养基配比由结果分析可知,当活菌数达到最大值时,即:乳糖的浓度为3.6%,酵母粉的浓度为1.74%,L-半胱氨酸的浓度为1.1%,牛肉蛋白胨1%,酪胨1%,KH2PO40.20%,Na2HPO40.20%,叶温-80 0.1%活菌数为最高2.34×109CFU/mL。结论采用响应面分析法优化的培养基较经典TPY培养基活菌数提高了近2～3倍。

Objective In order to reduce the costs of Streptococcus thermophilus industrial production and improve the number of viable cells in the fermentation product,the original composition of Streptococcus thermophilus medium was optimized by response surface methodology.Methods The significant factors which affect the growth of Streptococcus thermophilus were filtered out firstly through the Plackett-Burman experimental design by Design-Expert software,then the optimized ratio of Streptococcus thermophilus medium was obtained based on the response surface method.Results Lactose,yeast powder and manganese sulphate were the significant factors for the growth of Streptococcus thermophilus;The optimized medium ratio was as follows: lactose 3.6%,yeast powder 1.74%,L-Cysteine 1.1%,beef peptone 1%,casein peptone 1%,KH2PO4 0.20%,Na2HPO4 0.20% and Tween-80 0.1%;The maximum number of viable cells reached 2.34×109 CFU/mL.Conclusion The medium which is optimized by the response surface methodology to increased the mumber of viable cells nearly 2 to 3 times compared with the classic TPY medium