益生菌Lactobacillus plantarum P-8连续传代1000~2000代期间表型特征稳定性研究

Studies on the Stability of the Probiotic Lactobacillus plantarum P-8 during Long-term Continuous Subculturing from 1000 Generations to 2000 Generations by Assessing Its Phenotypic Characteristics

以1株益生乳酸菌P-8为研究对象,研究其表型特征的稳定性。以普通MRS培养基为培养基质进行长期连续传代,跟踪观测该菌株连续传代1 000~2 000代期间细胞形态、菌落形态、活菌数、浊度和菌株活力的变化情况。试验结果显示,乳酸菌P-8在1 000~2 000代期间细胞形态与菌落形态没有发生变化;活菌数与浊度均随培养代数的增加呈波动性变化（波动幅度较小）,而其总数基本维持不变;菌株活力也随培养代数的增加呈波动性变化,且差异不显著（P〉0.05）。研究表明,乳酸菌P-8的表型特征在长期传代（1 000~2 000代）过程中具有良好的稳定性。

In this study, a probiotic strain Lactobacillus plantarum P-8 was applied as the research object and standard MRS medium was applied for long-term continuous subculturing. The change of bacterial phenotypic characteris- tics, including the cell morphology, colony morphology, viable counts, growth （OD600） and activity, were investigated during the 1 000 generations to 2 000 generations. The results showed that, during 1 000 generations to 2 000 generations subculturing, there was no change in the bacterial cell and colony morphology of L. plantarum P-g, whereas the viable counts and growth of L. plantarum P-8 fluctuated mildly. Furthermore, the bacterial activity of L. plantarum P-8 was stable after subculturing. To some up, phenotypic characteristics of L. plantarum P-8 has favorable stability for long-term cultivation.