Abstract Arthrospira platensis , commonly known as spirulina, is a photosynthetically efficient cyanobacterium used for production of nutritional supplements, biofuel, wastewater treatment, and CO 2 sequestration. These traits and uses make it a candidate for bioregenerative life support systems for space travel and future habitats. However, A. platensis lacks a cryopreservation method for long-term storage of viable cells, and genetic stocks are currently sub-cultured for maintenance. Here we report an efficient cryopreservation method for A. platensis strain NIES-39 and adapt this method for an upcoming spaceflight experiment. Seven cryoprotective agents were tested to preserve viable A. platensis . We found that a combination of dimethyl sulfoxide and trehalose additives to Zarrouk’s media protected trichome viability for extended storage periods at -80 °C. Throughout one year of frozen storage, we observed equivalent viability of cryopreserved cells in comparison to non-frozen cultures. Equivalent cryopreservation was demonstrated with multiple volumes of frozen culture, culture containers, and thawing methods to adapt the method for delivery and return of viable NIES-39 for the Space Algae-2 experiment on the International Space Station. The method requires minimal resources, employs simple freezing and thawing procedures, and could be implemented in commercial production to preserve genetic stocks.
Fisher et al. (Tue,) studied this question.