cspL对保加利亚乳杆菌的影响研究

The influence of csp L on Lactobacillus bulgaricus

保加利亚乳杆菌是乳制品工业最常用的发酵剂之一,为了更好地保存保加利亚乳杆菌,对9株保加利亚乳杆菌(Lactobacillus delbrueckii subsp bulgaricus)在不同温度(-20、-40、-60℃以及-80℃)下冷冻保存7 d后的存活率进行了对比,同时利用RT-PCR分析对菌体中冷激蛋白csp L的含量进行了对比研究。结果显示,对于大多数菌株而言,-80℃较为适合冷冻保存,其存活率均在50%以上。同时,RT-PCR分析显示,csp L在不同菌株中的表达量具有显著差异,抗冷冻性强的菌株中csp L的含量明显高于抗冷冻性弱的菌株。因此,csp L的含量与保加利亚乳杆菌的抗冷冻性呈现正相关。

Lactobacillus delbrueckii subsp. bulgaricus is one of the most commonly used starter culture in dairy industry. In order to preserve the Lactobacillus bulgaricus efficiently, the survival rate of 9 Lactobacillus bulgaricus strains stored at different temperature（-20,-40,-60,-80 ℃） for 7 days were evaluated. Meantime, the expression of cold shock protein csp L in different strains were analyzed by RT-PCR. The results showed that-80 ℃ could be considered as the best temperature for strains presesrvation, the survival rate of most strains could reach to 50%. In addition, the expression content of csp L in the strains with high freezing resistance were higher than that in weak strains. So, we could conclude that csp L was positively correlated with the cold resistance of the Lactobacillus bulgaricus.