The cryopreservation of Chlorella. 2. Effect of growth temperature on freezing tolerance.

The temperature at which Chlorella 211/8h was grown determined the response to a subsequent stress of freezing to and thawing from-196 degrees C. Cells cultured at 20 degrees C were the most sensitive to freezing injury; at both higher and lower growth temperatures resistance to damage induced by freezing developed. At all culture temperatures examined the freezing tolerance varied with the age of culture.