Age: 27; Unaged
"Cryopreservation refers to the storage of a living organism at ultra- low-temperature such that it can be revived and restored to the same living state as before it was stored. Indefinitely long storage times require that the organism be maintained below the glass transformation temperature of aqueous solutions, approximately -130degC, the temperature at which frozen water no longer sublimes and recrystallizes. Although ultra-cold freezers may stabilize some living cells for weeks or even years, liquid nitrogen is required for longer storage times. Cyanobacteria, as is the case for all living cells, suffer severe osmotic stress and/or ice crystal damage during the freezing and thawing processes. The most effective known ways to minimize these potentially lethal effects are to add a cryoprotective compound to the culture prior to its freezing for storage, and to control the transient cooling and warming rates during preservation."
Cryopreservation of Cyanobacteria
By Jerry J. Brand, Botany Dept., Univ. of Texas at Austin