Published Jul 10, 2004

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Alberto Acosta


The stability in real time of four strains cryopreserved in 10% v/v of glycerol was evaluated during a 6-month period. The strains studied were Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae and Aspergillus niger. The Master Cell Bank (MCB), cryopreserved at -70ºC and -20ºC, was activated using two thawing protocols, a fast one (F) and a slow one (S). A better cell recovery was achieved with the -70ºC (F) protocol reaching a viability for Escherichia coli of 97.6% in the first 48 hours (p: 7.2x10-4). The viability was retained in the 4th (p: 1.5 x10-4), 5th (p: 4.6 x10-3) and 6th months (p: 1.9 x10-2). Bacillus subtilis retained a viability of 92.5% after the 2nd (p: 4.7x10-4), 4th (p: 1.76x10-1), 5th (p: 3.4x10-5) and 6thmonths (p: 3x10-2). Saccharomyces cerevisiae demonstrated a viability of 95% in the second month (p:9x10-3) and for Aspergillus niger, the viability was 94.8%, in the first 48 hours (p: 7.2 x10-4) and after the 4th month (p: 2.79x10-2). With the other protocols, -20ºC F and S, some changes in viability were observed due probably to the formation of eutectic mixtures, nucleation and re-crystallization processes. The Master Bank microbial purity was maintained at 100% during the time of the study.
How to Cite
Acosta, A. (2004). STUDY OF THE STABILITY IN REAL TIME OF CRYOPRESERVED STRAIN BANKS. Universitas Scientiarum, 9(2), 35–42. Retrieved from
Applied Microbiology

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