Cryocultures are indispensable not only for reproducible screening results, but especially for long-term production campaigns and for meeting regulatory expectations, which include master and working cell banks (MCB, WCB), for instance. These cultures enable consistent quality and yield in the production process, since fresh cells can be used and old ones discarded at specified intervals.
What is standard for bacteria and animal cell cultures still poses a challenge for plant systems in many cases. Although plant cell cultures are generally suitable for cryopreservation, there is currently no established method that can be applied to all types of plant cells, since protocols were tailored to individual cell lines. The conditions during pre-treatment, freezing and regeneration are often adapted to specific plants and plant cell types and are therefore difficult to transfer, scale and qualify.
At Fraunhofer IME, several cryopreservation protocols have been successfully developed for various cell lines, using various methods such as slow freezing, dehydration/desiccation and vitrification. The pre-conditioning with cryoprotective substances, the treatment with cryoprotective medium, the encapsulation with alginate, the freezing process, the thawing process, the washing process and the recultivation were therefore considered both individually and in combination.
In the Bioprocess Engineering department, we are currently working on merging these protocols and identifying parameters that enable a rational and systematic optimization for each specific plant cell lines.