FAQ - microorganisms

A freshly cultivated cell suspension of the microorganism is either dropped onto a pre-dried protectant/carrier or the culture suspension is mixed with a liquid protectant/carrier. Depending on the strain, different protectants/carriers are used leading to the different appearance of some of the pellets. In most cases, the protectant/carrier is the main component of the pellet. Therefore, when initially re-activating the strain the whole of the pellet must be resuspended and transferred into a small volume of medium (5-10 mL) so that the number of cells is sufficient for subcultivation.

The cell numbers present in a pellet differ due to strain-specific preservation conditions. Each lot is routinely checked for strain viability so that the DSMZ guarantees that a sufficient number of cells are present to allow successful reactivation and subcultivation.

All DSMZ ampoules are double vial preparations, sealed under vacuum. The outer vial has at the bottom humidity indicators consisting of blue or red Silica Gel. In the past some red Silica Gel batches did react inhomogeneous with a coloration varying from red, orange and colourless globules. This inhomogeneous coloration does not indicate automatically humidity inside the ampoule and influence on the viability or quality of the dried culture. We recommend opening and rehydration of the dried cultures in the inner vial even in case of ambiguous coloration of the Silica Gel. In case of problems during cultivation, please contact our customer support.

Several strains of fastidious microorganisms, especially strictly anaerobic bacteria, are suspended prior to lyophilization in a protectant mixture containing ferrous sulphide or charcoal, which gives the pellet a black colour.

Bacterial cell suspensions are dried together with a protectant. The pellet can be rehydrated for initial revitalization whereas phages are dried as suspensions on filter paper strips and require their host strain for initial propagation.