Journal of Culture Collections

Volume 3, 2000-2002

Influence of the freezing rate on the survival

of strains Saccharomyces cerevisiae

after cryogenic preservation

Tsonka Uzunova-Doneva* and Todor Donev

National Bank for Industrial Microorganisms and Cell Cultures, 1113 Sofia, P.O.Box 239, Bulgaria

Summary

Experiments for determination of the influence of the freezing rate on the viability preservation of brewery yeasts Saccharomyces cerevisiae were made. Six freezing rates were studied (0.3, 0.6, 1.0, 10, 30 and 300^oC x min^-1 ranging from 20^oC to minus 196^oC) and subsequent thawing at three different temperature values – 20, 27 and 37^oC was performed. It was established that the investigated strains 179, 181, 184 had maximum preserved their viability by freezing rate of 0.6^oCxmin^-1 and subsequent thawing in water bath at 37^oC. These results are applied for cryogenic preservation of brewery yeasts in the National Bank for Industrial Microorganisms and Cell Cultures (NBIMCC).

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