PB试验优化德氏乳杆菌增殖培养基的研究

试验对一株来源于传统酸奶的优良德氏乳杆菌（Lactobacillus delbrueckii）ATx生长所需的增殖因子进行了研究。在MRS培养基的基础上，测定了菌株ATx的生长曲线，并选取谷氨酸钠、磷酸吡哆醛、抗坏血酸、啤酒、乳糖、胡萝卜汁、番茄汁、pH为增殖因子。采用单因素试验确定每个因子的最优水平，Plackett-Burman试验考察各因子对菌株ATx细胞增殖的影响，通过最陡爬坡与中心组合试验对增殖因子进行优化。结果表明，谷氨酸钠、啤酒以及pH对菌株ATx的增殖具有显著影响（P＜0.05），当MRS培养基中添加谷氨酸钠21.5 g/L、啤酒26.8 mL/L、初始pH值为6.4时，德氏乳杆菌ATx的活菌数最大为（7.56±0.23）×109 CFU/mL，为高活性发酵剂的制备提供了理论参考。

Optimization of proliferation medium for Lactobacillus delbrueckii by PB experiments

The proliferative factors required for the growth of a high quality strain Lactobacillus delbrueckii, named ATx, which isolated from the traditional yogurt was studied. On the basis of MRS medium, the growth curve of strain ATx was determined and sodium glutamate, pyridoxal phosphate, ascorbic acid, beer, lactose, fresh carrot juice, tomato juice and pH were selected as proliferative factors. The optimal level of each factor was determined by single factor experiments, the effects of various factors on the proliferation of strain ATx cells was investigated by Plackett-Burman experiments, and the optimal proliferative factors were optimized by the steepest ascent and central composite tests. The results showed that sodium glutamate, beer and pH had a significant effect on the proliferation of strain ATx (P＜0.05). When the MRS medium components were monosodium glutamate 21.5 g/L, beer 26.8 ml/L, and when the initial pH was 6.4, the maximum viable count of strain ATx was (7.56±0.23)×109 CFU/ml, which provided theoretical references for production of starter culture with high viability.