Dewald R R
Appl Microbiol. 1966 Jul;14(4):561-7. doi: 10.1128/am.14.4.561-567.1966.
Water-washed Serratia marcescens (ATCC strain 14041) cells were lyophilized in an all-glass system capable of evacuation to pressures of less than 5 x 10(-6) torr. Lyophilization at the lowest pressures resulted in 50 to 65% survival for unstabilized washed organisms compared with 10 to 20% when the cells were lyophilized at pressures of about 2.5 x 10(-2) torr. At the latter pressures, 45 to 65% survival was obtained when NaCl or Naylor-Smith stabilizer was added to the cell suspensions before lyophilization. However, the stabilizers failed to increase significantly the levels of survival compared with water suspension when cells were lyophilized at pressures less than 10(-5) torr. The high survival rates obtained by the high-vacuum technique may be attributed to the reduction of traces of molecular oxygen which has been reported to be destructive of the dried bacteria. Survival of unstabilized dried S. marcescens after 1-day storage increased markedly with decreasing sealing pressure. Under the highest vacuum attained, survival of the dried bacteria was not impaired by storage for up to 1 month at Dry Ice temperatures; at higher temperatures, viability losses occurred. Exposure of the dried unstabilized bacteria to dry air resulted in rapid viability loss. The inactivation could be stopped almost immediately by evacuation to pressures of less than 10(-5) torr, but the evacuation failed to reverse the viability losses that occurred during exposure.
水洗粘质沙雷氏菌（ATCC菌株14041）细胞在一个能够抽真空至压力低于5×10⁻⁶托的全玻璃系统中进行冻干。在最低压力下冻干时，未稳定化的水洗菌存活率为50%至65%，而在约2.5×10⁻²托压力下冻干时，存活率为10%至20%。在后一种压力下，冻干前向细胞悬液中添加氯化钠或内勒 - 史密斯稳定剂，存活率可达45%至65%。然而，当细胞在低于10⁻⁵托的压力下冻干时，与水悬液相比，这些稳定剂未能显著提高存活率。通过高真空技术获得的高存活率可能归因于分子氧痕迹的减少，据报道分子氧对干燥细菌具有破坏性。未稳定化的干燥粘质沙雷氏菌在储存1天后的存活率随着密封压力的降低而显著增加。在达到的最高真空度下，干燥细菌在干冰温度下储存长达1个月，其存活率不受影响；在较高温度下，活力会损失。将干燥的未稳定化细菌暴露于干燥空气中会导致活力迅速丧失。通过抽真空至低于10⁻⁵托的压力，失活几乎可以立即停止，但抽真空无法逆转暴露期间发生的活力损失。
