响应面法优化豆乳链球菌增殖培养基

针对优良酸豆乳发酵菌株豆乳链球菌（Streptococcus sojalactis）SY1.1增殖培养基进行优化，研究碳氮源对豆乳链球菌生长的影响，并采用响应面法优化豆乳链球菌SY1.1的增殖培养基配方。结果表明：以AST为基础培养基，优选大豆蛋白胨和蔗糖为最适氮源和碳源，质量比为1∶2，采用Plackett-Burman设计对11 种促乳酸菌生长因子进行评价，利用中心旋转组合设计和响应面分析确定增殖培养基的配方为：蔗糖10 g/L、大豆蛋白胨20 g/L、磷酸氢二钾2 g/L、番茄汁85.8 mL/L、胡萝卜汁109 mL/L、玉米浆6 g/L，pH 6.8。SY1.1以接种量2%，在37 ℃培养12 h时，活菌数可达（8.9±0.2）×108 CFU/mL，较初始豆浆培养基的活菌数（1.03×108 CFU/mL）提高了7.64 倍。

Optimization of Culture Medium for Streptococcus sojalactis SY1.1 Using Response Surface Methodology

In this paper, response surface methodology was used to optimize the composition of AST-based culture medium
for Streptococcus sojalactis SY1.1 to obtain high density of bacteria. Through single-factor experiments, the optimum carbon
source and nitrogen source were found to be sucrose and soy peptone, respectively. The major medium components for
SY1.1 were screened by Plackett-Burman design. Then, the optimum culture medium was determined to consist of 10 g/L
sucrose, 20 g/L soy peptone, 2 g/L dipotassium phosphate, 85.8 mL/L tomato juice, 109 mL/L carrot juice and 6 g/L corn
steep liquor at pH 6.8 by central composite design and response surface analysis. The cell production of SY1.1 cultured in the
optimized medium for 12 h at 37 ℃ was (8.9±0.2) ×108 CFU/mL, which was 8.64 times higher than that (1.03×108 CFU/mL)
observed with soymilk as initial medium.