Chapter 18 Collection and Preservation of Frozen Microorganisms (original) (raw)

The storage of the different microorganisms over long periods is necessary to ensure reproducible results and continuity in research and in biomedical processes and also for commercial purposes. Effective storage means that a microorganism is maintained in a viable state free of contamination or genetic drift and must be easily restored without genotypic or phenotypic alterations to its original characteristics and properties. To this end, different techniques have been described and advances in cryopreservation technology have led to methods that allow low-temperature maintenance of a variety of cell types, minimizing the risks of genetic change and are now recommended for long-term storage of most microorganisms. This chapter summarizes the most important steps and components in the process of low-and ultra-low temperatures freezing of bacteria, parasites, yeasts and fungi, viruses, and recombinant microorganisms. Cryogenic preservation is the act of freezing and storing cells at very low temperatures. The effects of the freezing and thawing process on living cells are not fully understood: when water changes from liquid to solid state, cellular metabolism ceases and, when cells are warmed and water returns to liquid, cellular function resumes. Cell cryopreservation process remains the main method of cell preservation to date, and the high survival rates achieved by this method are of interest from both the biophysical and the practical points of view. Storing over long periods of bacterial or fungal strains, parasites, and viruses allows future research study, and it is essential for clinical, epidemiological, educational, microbiological, and commercial reasons. A special approach is required for the proper storage of recombinant microorganisms.