Tsvetkov T, Brankova R
Cryobiology. 1983 Jun;20(3):318-23. doi: 10.1016/0011-2240(83)90020-2.
Studies were conducted on the viability of Micrococcus varians strain M95 and Lactobacillus plantarum strain L4 upon freezing and freeze-drying using five cryoprotectants (sucrose, lactose, sodium glutamate, peptone, dry nonfat milk) singly or in combinations with gelatin, glutamic acid, and sodium acetate. The number of survivals was determined immediately after treatment and after storage at room temperature or refrigeration temperatures, under vacuum or in air. Dry nonfat milk and peptone introduced at the levels of 8 and 5%, respectively, to broth culture, were found to be the best cryoprotectants providing a 100% viability determined immediately after the treatment of the strains under investigation. Immediately after freezing and freeze-drying, the numbers of viable micrococci remain high, the percentage viability in the presence of almost all the protectants used being 100%. During storage, those numbers decrease rapidly, reaching zero in 3 months upon storage at room temperature in air. The storage ability of lactobacilli is considerably better and, regardless of the fact that the percentage viability decreases, sufficient numbers of viable cells remain after 6 months of storage at both test temperatures. The best results are obtained on storing the microorganisms under vacuum in ampoules under reduced temperatures (+5 degrees C).
使用五种冷冻保护剂（蔗糖、乳糖、谷氨酸钠、蛋白胨、脱脂奶粉）单独或与明胶、谷氨酸和醋酸钠组合，对变异微球菌菌株M95和植物乳杆菌菌株L4进行冷冻和冻干后的活力研究。处理后以及在室温或冷藏温度下、真空或空气中储存后，立即测定存活数。分别以8%和5%的水平添加到肉汤培养物中的脱脂奶粉和蛋白胨，被发现是最佳的冷冻保护剂，在所研究的菌株处理后立即测定的存活率为100%。在冷冻和冻干后立即，存活的微球菌数量仍然很高，几乎所有所用保护剂存在下的存活率百分比为100%。在储存期间，这些数量迅速减少，在室温空气中储存3个月后降至零。乳酸杆菌的储存能力要好得多，并且无论存活率百分比下降，在两个测试温度下储存6个月后仍有足够数量的活细胞。在低温（+5℃）下将微生物真空保存在安瓿中可获得最佳结果。
