Deployment of the encapsulation-dehydration protocol to cryopreserve microalgae held at the Sammlung von Algenkulturen, Universitat Gottingen, Germany

Encapsulation-dehydration was applied to cryopreserve 14 diverse algal strains, representing eukaryotic terrestrial microalgae; of these 12 survived to form cell colonies after recovery from cryostorage. Surviving algae had varying degrees of tolerance to osmotic dehydration and desiccation in this vitrification-based cryoprotective strategy. The extent of algal regrowth was affected by the mode of desiccation (silica gel or air-flow), the duration of evaporative desiccation and exposure to light during early recovery phase. This paper: (i) demonstrates the versatility of the encapsulation/dehydration method to cryopreserve diverse microalgae; (ii) confirms the successful transfer of this cryostorage technology to the Culture Collection of Algae at Gottingen University (SAG); and (iii) recommends encapsulation/dehydration as a feasible alternative to controlled rate cooling for preserving algae held in international culture collections.