Introducing the concept and application of vitrification for the cryo-conservation of algae - a mini-review

This review pertains to a project (COBRA QLRT-2000-01645, http://www.cobra.ac.uk) supported by the European Commission's Fifth Framework Programme for Quality of Life and Management of Living Resources. The aim of this initiative is to develop and apply novel cryo-preservation protocols to microalgae and cyanobacteria that are difficult to cryopreserve. One such approach utilizes cryoprotective vitrification for the conservation of algal culture collections at -196degreesC in liquid nitrogen. Achieving a vitrified state depends on increasing cellular viscosity to a critical point at which water forms an amorphous, non-crystalline glass on cooling to ultra-low temperatures. Vitrification has been utilized extensively in medical cryobiology and for the preservation of animal, human and higher plant germplasm but its application for the conservation of algae and cyarlobacteria is less widespread. The review provides a theoretical introduction to vitrification and highlights current and potential applications in algal preservation, especially for storage-recalcitrant organisms.