鼠李糖乳杆菌LV108传代的稳定性

Research on subculture and genetic stability of Lactobacillus rhamnosus LV108

为了对鼠李糖乳杆菌LV108在连续传代过程中的遗传稳定性进行研究。通过测定鼠李糖乳杆菌LV108在传代过程中发酵特性、益生特性的变化，并用RAPD方法分析不同传代菌株基因组的变化。结果表明，LV108经过20代传代后，其发酵乳pH值、酸度、持水力、黏度均未发生显著变化；耐酸及耐胆盐能力无显著变化，在pH值为3．0和胆盐质量分数0．3％的培养基中，存活率分别大于90％和45％；对大肠杆菌和金黄色葡萄球菌均为中度抑制以上，在传代过程中变化不显著；α—ALDC，LDH，α—Gal酶的活力在传代过程中也较为稳定。统计分析20个引物PCR扩增指纹图谱中的各类扩增带，基因组相似率在0．9761～0．9973之间，在传代过程中各代菌株基因组之间具有极大的相似性。因此，LV108可作为良好的发酵菌株应用于工业生产中。

To analyze the stability of Lactobacillus rhamnosus LV108 in a continuous passaging process.The fermentation properties and probiot- ic properties of lactic acid bacteria strains were measured, and RAPD method were used to analysis the different algebraic genomic changes in LV108.The results showed that Lactobacillus rhamnosus LV108 have a good stability, pH, acidity, water holding capacity viscosity of the fer- mented milk were not significantly changed （P〉0.01）. LV108 had good acid and bile salt resistant ability, which were cultured 2h in Medium of pH3.0 and medium containing 0.3% bile salts, the survival rates were greater than 90% and 45% respectively. It＇s antimicribial activity were not changed significantly （P〉0.01）, Escherichia coli and Staphylococcus aureus were more moderate suppressed by LV108. LV108 had stable enzyme activity of ALDC, LDH and oL -Gal （P〉0.01）. The enzyme activity were respectively at around 0.080-0.087 U/mL, 0.331-0.334 U/mL and 1.326-1.341 U/mL.20 random primers were used to amplify genomic DNA, and all kinds of amplified bands in fingerprint were analyzed.Similarity of genome were between 0.9840-0.9973,and each generation strains genome have great similarity during subculture. Therefore, as a good fermentation strain, LV108 could be used in industrial production.