植物乳杆菌Lp-S2直投式发酵剂及其离心、冷冻干燥工艺研究

Study on centrifugal and freeze drying of Lactobacillus plantarum Lp-S2 DVS

以高产γ-氨基丁酸的植物乳杆菌Lp-S2为出发菌株,研制直投式发酵剂。并对发酵剂离心工艺及冷冻干燥工艺进行优化。通过正交试验确定植物乳杆菌Lp-S2的离心工艺为:离心温度4℃,离心时间30min,转速6 000r/min,该条件下植物乳杆菌Lp-S2离心收得率为83.8%。通过单因素和正交试验进行冷冻保护剂的优化。冷冻保护剂的最佳组合是15%海藻糖,15%葡萄糖和10%脱脂乳粉。植物乳杆菌Lp-S2直投式发酵剂,冻干存活率为39.2%,最佳预冷时间为6h。直投式发酵剂活菌数达到1.5×1012 CFU/mL。

Lactobacillus plantarum Lp-S2 which has the ability to produce gamma-aminobutyric acid, was used as starting strain to develop Direct vat set （DVS）. Then the centrifugation process and freeze-drying process were optimized. By orthogonal experiment the optimal conditions of centrifugation were identified as： centrifugal temperature 4 ℃, Time-consuming 30 minutes, centrifugal force 6 000 r/min. In this condition, the centrifugal recovery rate of Lactobacillus Lp-S2 is 83.8%. The cryoprotectant was optimized by single factor and orthogonal test. The best combination of cryoprotectants was 15% trehalose, 15% glucose and 10% skim milk powder. The survival rate of L. plantarum Lp-S2 Direct Vat Set reached 39.20/00. The optimum pre-eooling time was 6 h. The number of viable cells of the direct-acting starter was 1.5 × 10^12 CFU/mL.