钙离子对植物乳杆菌LIP-1抗冷冻干燥性能的影响

本文以植物乳杆菌LIP-1为研究对象，探讨在培养基中添加不同浓度的钙离子对菌株生长量及抗冷冻干燥性能的影响，在此基础上，研究了不同浓度钙离子对菌体形态、细胞壁及细胞膜结构完整性以及细胞膜脂肪酸构成的影响，以探讨钙离子影响菌株抗冷冻干燥性能的机制。结果表明:当在MRS培养基中添加0.5 mmol/L的钙离子时，与未添加钙离子的对照组相比，菌株的生长量提升了0.717×109 CFU/mL，存活率提升了21.52%（P<0.05）；同时与对照组相比，添加钙离子可以使植物乳杆菌LIP-1长度明显变短；菌株的细胞壁与细胞膜的损伤程度降低；细胞膜中不饱和脂肪酸的含量升高，U/S变大；添加钙离子还可以使菌株的常温贮藏稳定性得到提高，第8周时添加钙离子的实验组相较对照组（MRS）活菌数提升了13.65倍。该结果为培养基中添加适量的钙离子促进菌体生长以及提高菌株的抗冷冻干燥性与贮藏稳定性提供了理论参考。

Effect of Calcium Ions on the Freeze-drying Resistance of Lactobacillus plantarum LIP-1

Taking Lactobacillus Plantarum LIP-1 as a research object, this article explored the growth and the freeze-drying resistance of the strain by adding different concentrations of calcium ions to the culture medium. To understand the mechanism of calcium ions on the freeze-drying resistance of strain, the morphology, cell wall of the bacteria, the structural integrity of cell membrane and the fatty acid composition of cell membrane were studied. The results showed the growth of the strain increased by 0.717×109 CFU/mL and the survival rate increased by 21.52% (P<0.05), when 0.5 mmol/L calcium ions were added to the MRS medium, compared with the control group without calcium ions. Moreover, the length of Lactobacillus Plantarum LIP-1 becomed shorter, the damage to the cell wall and cell membrane of the strain was reduced, the content of unsaturated fatty acids in the cell membrane increased, and the U/S becomed larger. More importantly, the storage stability of the strain at room temperature was improved. We founded that the number of viable bacteria in the experimental group increased by 13.65 times compared with the control group (MRS) at the 8th week. Our result provides a theoretical reference for promoting the growth of bacteria and improving the freeze-drying resistance and storage stability of the strain by adding appropriate amount of calcium ions to the culture medium.