title: Cryopreservation of a marine microalga, Nannochloropsis oculata (Eustigmatophyceae).
abstract: The cryopreservation of algae could prevent genetic drift and minimize labor costs compared to the current method of maintenance and subculturing. Clear, simple protocols for cryopreservation of marine microalga, Nannochloropsis oculata were developed and cryoprotectant choice and concentration optimized. The viability of the microalga was assessed directly after thawing, and algal concentration was measured after 2-30 days of growth. Five cryoprotectants (dimethyl sulphoxide, Me2SO; ethylene glycol, EG; glycerol, Gly; methanol, MeOH; and propylene glycol, PG) at five concentrations (10, 20, 30, 40, and 50%; v/v) were evaluated to determine the toxicity of various cryoprotectants to N. oculata. The toxicity of cryoprotectant (Me2SO, EG, MeOH, and PG) was observed only at higher concentrations of CPAs: > 20% for EG, > 30% for Me2SO and methanol, and > 40% for PG. Direct freezing of algae in liquid nitrogen resulted in a severe loss of viability and a modified cryopreservation protocol proved to be more appropriate for the preservation of N. oculata. Cryopreservation protocols developed and tested in the present study might be applied to cryopreserving other strains, or species, in this genus.
authors.affiliation: Department of Aquaculture, Taiwan National Ocean University, Keelung 20224, Taiwan. gwonet@ms16.hinet.net
authors.forename: Jin-Chywan
authors.initials: JC
authors.lastname: Gwo
authors.forename: Ju-Yu
authors.initials: JY
authors.lastname: Chiu
authors.forename: Chin-Cheng
authors.initials: CC
authors.lastname: Chou
authors.forename: Hsien-Yu
authors.initials: HY
authors.lastname: Cheng
mesh_terms: D000818:Animals; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000633:toxicity*; D004121:Dimethyl Sulfoxide / Q000633:toxicity; D019855:Ethylene Glycol / Q000633:toxicity; D056890:Eukaryota / Q000187:drug effects* / Q000502:physiology*; D005990:Glycerol / Q000633:toxicity; D008386:Marine Biology / Q000379:methods*; D000432:Methanol / Q000633:toxicity; D019946:Propylene Glycol / Q000633:toxicity
chemical_list: D003451:Cryoprotective Agents; D019946:Propylene Glycol; D019855:Ethylene Glycol; D005990:Glycerol; D000432:Methanol; D004121:Dimethyl Sulfoxide