ASSESMENT OF CRYOPRESERVATION SYSTEMS INFLUENCE ON THE SURVAVIAL OF E. COLI RECOMBINANT STRAINS

Abstract

The cryopreservation systems of recombinant bacterial cells based on glycerol were studied in these experiments according to the hypothesis that glycerol is one of the widely used cryoprotective additives in microbiology and a multitude of factors affecting the effectiveness of cryopreservation in microorganisms; the best cryoprotective additive and the optimum concentration for a particular microorganism has to be determined empirically. The results obtained in this experiment are showing that the freezing procedure at -80°C in LB 40% glycerol is the optimum system for the cryopreservation of E. coli DH5α recombinant cells. The use of SOC medium supplemented with 10g/l NaCl provided more proper conditions of culture for the defrosted E. coli DH5α recombinant cells, reducing the osmotic stress during the recovery after thawing. The utilization of this optimum cryopreservation system offer the possibility of preserving the large volume of work and time involved by the recombinant DNA technology procedures applied for obtaining a recombinant strain, avoiding the storage of recombinant strains by costly and time consuming microbiology culturing techniques.

Keywords

• cryopreservation system
• recombinant bacteria survival
• bacteria culture