The Stability of the Biochemical Parameters of E. Coli with Different Methods of Preservation

Abstract

The effect of four routine methods of preservation of bacteria (in Dorset medium, under mineral oil, freeze-drying, cryoconservation in liquid nitrogen) on the biochemical characteristics of 11 E. coli strains from the collection of NBIMCC, was followed up. After 1 and 3 years of preservation, half of the strains changed their biochemical activity, 33 % of the parameters examined having turned into negative. The biochemical characteristics of the strains studied turned out to best preserved in Dorset medium and under mineral oil. Freezedrying is appropriate for long-term preservation but it requires additional following up of the biochemical parameters.