Proceedings: The phospholipid degradation and cellular death caused by freeze-thawing or freeze-drying of yeast

Freeze-thawing or freeeze-drying of yeast cells increased the amount of total lipid and phospholipid extractable to the level of the cell's total lipid contents. However, the amount of total lipid and phospholipid extractable from intact cells was usually less than half of these values.Phospholipase activity was apparent after freeze-thawing or freeze-drying of the cells, and phospholipids in the cells were decomposed to diglyceride and phosphoryl groups. Lipase activity was higher at pH 3–4.5, but at pH 6, practically no activity was noted.The cells incubated in medium at pH 6 after freeze-thawing or freeze-drying showed higher survivals than the cells incubated at pH 4.4 after the same treatments.