副干酪乳杆菌ET-22连续传代1000代的稳定性研究

Study on the Stability of Lactobacillus paracasei ET-22 During 1000 Continuous Subculturing

本研究以自主优良益生菌副干酪乳杆菌ET-22为研究对象,研究以MRS培养基进行长期连续传代过程中其表型特征和遗传信息的稳定性,跟踪检测该菌株连续传代1000代期间细胞形态、菌落形态、生长性能、发酵活力和基因序列变异情况。结果显示,副干酪乳杆菌ET-22在连续传代1000代期间细胞和菌落形态没有发生变化,活菌数、浊度和菌株活力呈上下小幅度波动,变化不显著;基因组重测序分析显示,0~600代内无变异位点,800和1000代分别监测到2个和4个SNP位点,未达到菌株变异水平。研究结果表明副干酪乳杆菌ET-22在连续传代1000代期间表型特征和遗传信息维持稳定。

In this study,a independently developed probiotic strain Lactobacillus paracasei ET-22 was applied as the research object and MRS was used for long-term continuous subculturing.The changes of the cell morphology,colony morphology,growth performance,fermentation activity and gene sequence variation of the strain were investigated during 1,000 generations.The results showed that,during 1,000 generations continuous subculturing,there was no change in the cell and colony morphology of L.paracasei ET-22,meanwhile the number of viable bacteria,turbidity and bacterial activity fluctuated slightly.Moreover,the results of genome resequencing showed that there were no SNP sites during 600 generations,but two and four SNP sites during 800 and 1,000 generations.To sum up,phenotypic characteristics and genetic information of the L.paracasei ET-22 have favorable stability for long-term cultivation.