氧气对干酪乳杆菌生长和活力的影响

Influence of oxygen to the growth and survival of Lactobacillus casei

以静置培养为对照,通过振荡培养制造有氧环境,对干酪乳杆菌的生长曲线、菌体活力进行分析。研究发现在有氧条件下菌体生长受到抑制,菌体密度小于静置发酵,在4℃保存时的活力迅速下降,另外,有氧生长菌体对热、胆汁等条件的耐受性较差,在50℃处理4h导致菌体迅速死亡,在含有胆汁的培养基中,菌体生长几乎停滞。通过透射电镜观察发现有氧条件下菌体细胞壁发生破裂,菌体细胞质成分溶出,导致菌体死亡。因此,氧气对干酪乳杆菌的生长具有抑制作用,造成细胞损伤,导致菌体活力降低。

The growth curve and survival of L.casei under aerobic and anaerobic conditions were obtained by culturing with and without shaking respectively.The growing of L.casei inhibited by oxygen,which had a decreased growth yield compared with standing fermentation and a survival of reduced rapidly when stored at 4℃.Aerobic cultured L.casei had a bad tolerance in MRS media contain 0.3% bile,which also made a dominant cells death by treating with 50℃ for 4 hours.The cell walls rupturing and cytoplasm of aerobic cells dissolution were observed by transmission electron microscope,which induced the death of cells.Accordingly,influence of oxygen to L.casei was inhibiting growth,breaking cell walls and leading to poor survival.