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  • A DSM number is cited in the literature but we cannot find the strain on the homepage. What is the reason?

    One reason may be that the strain has been lost or, after publication of the description, turned out not to show the characters given for the taxon. Another reason may be that the strain was deposited for patent purposes. These strains and their data are kept confidential by the DSMZ. If you have the well-founded guess that the latter is true for your strain in question you may contact Dr. Felizitas Bajerski or Dr. Kathrin Felsch. They will give details on how to obtain a culture of the strain.

  • We wish to store a strain we obtained from the DSMZ, what methods should we use?

    Once strains obtained from the DSMZ have been sub-cultured in a customer’s laboratory the methods used for long-term storage are best investigated in the customer’s laboratory. Since the DSMZ holds more than 84,000 strain it is impossible to give exact details for each strain. However, the DSMZ generally stores the majority of its Bacteria and Archaea in liquid nitrogen and/or freeze dried. Some strains are also stored at -80°C. The methods used in the DSMZ and in other collections for long-term storage of Bacteria and Archaea have been published in the book:

    Day, J.G. & Stacey, G.N. (2007). Cryopreservation and Freeze-Drying Protocols. Methods in Molecular Biology Volume 368 2007 ( in the chapter Vacuum-Drying and Cryopreservation of Prokaryotes (

  • Why are there sometimes two risk groups stated for one organism: according to TRBA and ZKBS?

    In some cases the ZKBS (Central Committee on Biological Safety), the responsible organ for the classification of biological material in connection with genetic engineering, classifies an organism differently than the TRBA (Technical Rules for Biological Agents). The DSMZ wants to inform its customers about an allocation in a higher risk group to make them aware that the organism might pose a higher risk than its legal allocation according to the Federal Institute for Occupational Safety and Health (BAuA) implies.

  • Can I receive certificates for the strains I ordered stating that they are free of components of animal origin or components bearing TSE / BSE (Transmissible Spongiforme Encephalopathy / Bovine Spongiforme Encephalopathy)?

    No, the DSMZ does not certify such data. The providers of media and other products may be in a position to certify this information. The DSMZ Department of Microorganisms only uses high-quality providers' products. Please, also remember that according to our Terms & Conditions microorganisms supplied by the DSMZ are for in vitro use only.

  • What is the expiry date of freeze-dried cultures in unopened ampoules?

    The DSMZ does not set an expiry date on freeze-dried cultures. Our Terms and Conditions state that all cultures are meant for immediate use only, indicating a warranty period of four weeks. Most freeze-dried strains can be stored for a much longer period, especially when kept under optimal conditions. However, the DSMZ will not certify a fixed date after which ampoules have to be discarded.

  • How to reactivate fastidious bacteria from ampoules?

    For many fastidious organisms a higher inoculum is needed to reactivate them. Add 0.5 ml of adequate liquid medium (given for each strain in its specific strain entry) to the pellet and dissolve the pellet as quickly as possible, then dilute the suspension with 4.5 ml of the same medium. For strains that grow only on plates but not in liquid media, distribute at least 1 ml suspension on each agar plate. If the strain does grow also in liquid medium use 1 ml for inoculation of 5 ml liquid medium, plate the rest on agar plates also using 1 ml suspension per plate. In some cases it is recommended to resuspend the material of one ampoule in 1 ml and plate it completely onto one single agar plate. This is then mentioned in the specific strain entry.

  • If no liquid medium is recommended in the specific strain entry, which solution do I use to solubilize the freeze-dried pellet (reactivation) or to cultivate the strains in liquid medium?

    Generally, use the recommended medium without the addition of agar. For fastidious microorganisms which grow only on solid media (e.g. M 693; M 429; M 585) use complex liquid media like M 1; M 545 or M 92.

    Please keep in mind: it is better to use any peptone or casamino acid or yeast extract containing medium than water or buffer for the solubilization of the pellet.

  • What does the ampoule pellet consist of?

    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.

  • Why do some ampoules contain a black pellet?

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

  • Which documents and working permits have to be sent to the DSMZ before despatch of the strain?

    Sending applicable working permits with the order accelerates the process of the ordering procedure (in Germany: Infektionsschutzgesetz, TierSeuchG, PflanzenbeschauVO, GenTG, etc respectively, dependent on the biological material requested).

  • In which form will the microorganism ordered be sent, freeze-dried or as actively growing culture?

    The forms of delivery are indicated for every individual strain in the respective strain entry on our website. In case a strain is not available in freeze-dried form, it will be sent as an actively growing culture the fee of which is slightly higher than for a freeze-dried culture. In the case of an order for an actively growing culture where a freeze-dried culture is available, the fee is higher due to the additional work required. For details please see our price list.

  • How are subcultures of a strain obtained from the DSMZ best prepared?

    Please, follow all instructions provided on the "Handling and Safetey Information" brochure accompanying your cultures consignment regarding the re-activation of freeze dried strains. This information is also available as download here.
    We also provide video tutorials for handling aerobes and anaerobes.
    Additional information on a variety of other organisms including myxobacteria, streptococci, enterococci, methanogens, acidophiles etc. can be found here.

    Actively growing cultures are best sub-cultured using the medium and growth conditions listed on our website under the strain specific information. See our FAQ “Which growth conditions are recommended by the DSMZ for a particular strain?”


  • What are the storage conditions of actively growing cultures?

    Actively growing cultures have to be subcultured under the correct conditions immediately after receipt. Psychrophilic and mesophilic microorganisms should usually be kept in the refrigerator before they are used unless otherwise stated. Especially sensitive, hyperthermophilic or obligately acidophilic strains should be kept at room temperature until used.

  • How long is the viability of cells in opened ampoules?

    The complete content of an opened ampoule has to be resuspended immediately in the appropriate medium given in the strain entry on our website, otherwise the cells will die rapidly.

  • How should unopened ampoules be stored?

    Freeze-dried ampoules are stored at 10°C in the dark in the DSMZ. According to our Terms & Conditions, the material is to be used immediately upon receipt and the DSMZ can only accept claims for products where tests for viability have been made immediately after receipt. The DSMZ accepts no responsibility for the viability of material stored for extensive periods of time outside of the DSMZ.

    Where possible the DSMZ ships strains of microorganisms that have been dried under vacuum. While the DSMZ uses the generic term "freeze-dried" the actual methods may deviate slightly. Strains shipped as "freeze-dried" vials are usually stable when shipped without cooling or in dry ice. Excessive temperatures should be avoided.

  • What is important when growing plasmid-bearing strains?

    Growth media should contain those agents selective for the plasmids to avoid plasmid loss.

  • Does the DSMZ provide isolated plasmid DNA?

    No, plasmids are only offered within their host bacterium.

  • Why do some ampoules contain blue, others red humidiy indicator?

    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 colorless 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 the case of ambiguous coloration of the Silica Gel. In case of problems during rehydration, please contact DSMZ.

  • How many cells does an ampoule contain?

    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.

  • Which batch number/culture transfers in the sense of lab standards are DSMZ ampoules or actively growing cultures?

    Our freeze-dried microorganisms in glass ampoules are batch no. zero, actively growing cultures are batch no. one.

  • Does the DSMZ provide plasmid sequences or maps?

    No, we refer to published literature that are given as a DSMZ literature reference number for most plasmids.

  • How do I know the lot no. of an ampoule and what does it mean?

    The preservation date on the inner vial is the lot identification. Viability and authenticity of each strain is routinely tested at the DSMZ so that ampoules that are several years old can be used without problems. Actively growing cultures are freshly prepared before despatch.

  • Does deposit of a strain in the DSMZ public collection cost anything?

    Deposit of biological material in the public collection of the DSMZ is free.

    Charges for the deposit of strains for patent purposes or as a safe deposit are provided in our price list.

  • What is the correct procedure for deposition of a strain in the public DSMZ collection?

    Please follow the steps described here exactly, use our accession form and please do not send us cultures without contacting us first.

  • What is important for correct packaging and shipment of microorganisms?

    The DSMZ provides detailed information under safety Instructions. Please make sure that the material you are sending is properly packed in a triple containment packaging system.

  • Can I receive certificates for the strains I ordered?

    A strain-specific certificate on authenticity, origin and quality is printed on each delivery document. All lots of our strains are checked for strain authenticity with strain-specific methodologies. Additional information is not generally provided.

  • Does the DSMZ provide a Safety Data Sheet?

    The DSMZ provides a comprehensive, general, not strain-specific safety data sheet. Individual safety data sheets are provided on request.

  • Where can I find information on phages?

    Comprehensive information on phages, phage-specific methods and a separate FAQ list on the phage collection can be found on our phage page.

  • What is a type strain and how is this documented in the DSMZ catalogue?

    A type strain is defined in the “International Code of Nomenclature of Bacteria” as the “nomenclatural type of the species”, and is the "reference point" to which all other strains are compared to know whether they belong to that species. Type strains are marked as such and can be searched by ticking the relevant box when conducting a catalog search for e.g. bacteria.

  • Where can I find more information on a particular strain?

    All information we have on a strain can be found on our homepage. This information may be found by conducting a search in the online catalogue using the DSM number or species name. In the list of strains found clicking on the DSM number will take you to the complete strain information. Further details can be accessed via our databases. You will find a direct link to associated data on the right site of each strain entry in the online catalogue.

  • How do I know the history of a strain?

    The history of a strain (known to the DSMZ) can be found in our online catalogue in the individual strain entries. The information is given in chronological order, with the most recent holder of the strain to the left, the oldest holder of the strain to the right.

  • Which growth conditions are recommended by the DSMZ for a particular strain?

    All catalogue entries on our homepage indicate the cultivation conditions recommended by the DSMZ. These include both the medium and temperature used in the DSMZ for cultivating the strain. We recommend that only these cultivation conditions be used when initially re-activating a freeze-dried strain or for the initial sub-culturing of an actively growing strain. This information is found by conducting a catalogue search using the DSM number or species name. In the list of strains found clicking on the DSM number will take you to the complete strain information. Additonial information about the used cultivation media can be obtained from our MediaDive database.

    Special tips for cultivating certain groups of organisms can be found under here.

  • Are packages X-rayed during the air transportation chain?

    It is not possible for the DSMZ to prevent packages from being security-checked. Forwarders in the transport chain decide about security checks of freight before freight is entering an aircraft. Cultures should be grown as usual.