I´ve been trying to obtain valuable viable bacteria by freeze-drying of the fermentation broths, but ended up with a crystalline hard film. I would to obtain fine and smooth powders, similar to commercially available microbial cultures (e.g. ATCC). Freeze-drying conditions were -40°C and
Freeze drying is also used in manufacturing of raw materials for pharmaceutical products. Active Pharmaceutical product Ingredients ( APIs ) are lyophilised to achieve chemical stability under room temperature storage. Bulk lyphilisation of APIs is typically conducted using trays instead of glass vials, Dry powders of probiotics are often produced by bulk freeze - drying of live microorganisms such as Lactic acid bacteria and Bifidobacteria.. For more details consult https;''www.en.wikipedia.org
You can find some useful hints in the report of the EMbaRC project:
http://www.embarc.eu/deliverables/EMbaRC_D.NA1.1.1_D2.36_SOPs_Acquis_Preserv_Ctrl.pdf
Thank you very much Andrey. The information is very useful indeed. I still need a bit more details but this is good as a start.
Rogelio Valadez-Blanco : The common practice is not to freeze-dry bulk fermentation broth with biomass. The fermentation broth components may be the reason why you obtained after freeze drying a crystalline hard film. Usually the biomass is separated from a fermentation broth by centrifugation and then is washed to remove as much as possible of fermentation broth from biomass. After this obtained biomass is mixed with some protective material (ex. trehalose, skimmed milk, etc....) and then is freeze dried. The obtained material can be easily pulverized. Such a protocol is commonly used in practise for freeze drying of a bacterial biomass.
Best regards
Vit
Dear Vit Mateju. Thank you very much for your thoughtful and practical response, and for sharing your knowledge. I will apply this in the lab for bacterial preparations.
Best regards,
Rogelio.
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