Preservation of Chlorella SP by cooling and freezing

Abstract

Cultures of Chlorella sp previously centrifuged and not centrifuged were kept in a refrigerator and freezer (without cryoprotector) with the purpose to test the possibility of preservation of this microalgae through periods from 1 to 28 months. It was observed that this species can be maintained by cooling as well as by freezing until 28 months. However, the cooled and previously centrifuged material grew up fastly and better than the materials from the other treatments, reaching density to 10 x 10ⶠcells/mL in a few days after each storage period. The lag phase became longer when the storage period increased. After the 9th month of storage the recovering time was considerably longer. The preservation of centrifuged cultures in a domestic refrigerator is a simple method which may be utilized in aquaculture for it makes possible the storage of a great number of cells in a small volume.