Preservation of Microorganisms for Storage in Culture Collections.

Microbial culture collection centers are pivotal for preserving and providing microorganisms for scientific and industrial applications. Proper preservation methods, like freezing or drying, are crucial. Cryostorage in the vapor or liquid nitrogen (LN) phase at temperatures below -150°C is used to ensure that the biological material is stored genetically unaltered. In addition, microorganisms are preserved as dried lyophilizates using appropriate freeze-drying protocols, where applicable. Maintaining the quality of source material through optimal growth conditions is also essential, and can be found in species descriptions, in culture collections catalogs, or online databases. This applies in particular to microorganisms that are difficult to cultivate and is of crucial importance for preservation, but is often a challenge due to the laborious cultivation process. The protocols described in this chapter represent examples of how microorganisms in culture collections are preserved at the Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures GmbH.