植物乳杆菌冻干保护剂的优化研究

Optimization of Freeze-Drying Protectant Agent for Lactobacillus Plantarum

为提高植物乳杆菌冻干存活率和研发以植物乳杆菌冻干菌粉为基础的直投式复合发酵剂,以植物乳杆菌L5、L12为试验菌株,在Plackett-Burman试验设计和最陡爬坡试验的基础上采用响应面分析优化了植物乳杆菌L5、L12真空冷冻干燥的保护剂配方,并进一步优化了植物乳杆菌L5、L12冻干菌粉最佳复配比例。结果表明:植物乳杆菌L5最佳冻干保护剂配方为:脱脂乳30.98 g/100 mL、海藻糖22.15 g/100 mL、硫酸锰0.19 g/100 mL,菌体存活率预测值为82.43%,验证试验实际值为82.55%;植物乳杆菌L12最佳冻干保护剂配方为:脱脂乳15.98 g/100 mL、海藻糖10.85 g/100 mL、硫酸锰0.05 g/100 mL,菌体存活率预测值为84.05%,验证试验实际值为83.66%。植物乳杆菌L5、L12的冻干菌粉最佳复配比例为3:1,在该条件下,其产酸能力较好、生长速度较快、亚硝酸盐降解能力最强(90.76%)。研究结果可为开发商品化专用直投式发酵菌剂提供技术支撑。

In order to improve the freeze-drying survival rate of Lactobacillus plantarum and develop a freeze-dried Lactobacillus plantarum-based direct-vat-set composite culture,this study used Lactobacillus plantarum L5 and L12 as the experimental strain.Based on Plackett-Burman design and steepest ascent experiment,the protective agent formulas for Lactobacillus plantarum L5 and L12 subjected to vacuum freeze-drying were optimized by response surface methodology,and the optimal proportion of the lyophilized powder of Lactobacillus plantarum L5 and L12 were further optimized.The results showed that the optimal cryoprotectant formulations of Lactobacillus plantarum L5 respectively was:skim milk 30.98 g/100 mL,trehalose 22.15 g/100 mL,manganese sulfate 0.19 g/100 mL,the predicted value of the bacterial survival rate was 82.43%,and the actual value of the verification test was 82.55%.The optimal cryoprotectant formulations of Lactobacillus plantarum L12 respectively was:skim milk 15.98 g/100 mL,trehalose 10.85 g/100 mL,manganese sulfate 0.05 g/100 mL,the predicted value of the bacterial survival rate was 84.05%,and the actual value of the verification test was 83.66%.The optimal ratio of freezedried Lactobacillus plantarum L5 and L12 powder was 3:1.Under such conditions,compound Lactobacillus plantarum had a good acid production capacity,a fast growth rate and the strongest nitrite degrading ability(90.76%).This study can provide technical support for the development of commercial special direct-vat-set composite culture.