Effect of different light regimes on the docosahexaenoic acid (DHA) content of Isochrysis aff. galbana (clone T-ISO)

• Main Authors: Tzovenis, I, De Pauw, Niels, Sorgeloos, Patrick
• Format: Article in Journal/Newspaper
• Language: English
• Published: 1997
• Subjects: Biology and Life Sciences; docosahexaenoic acid (DHA); clonal variation; factorial optimization; light limitation; photoperiod; T-ISO; CLAM TAPES-PHILIPPINARUM; MARINE UNICELLULAR ALGAE; SCOPHTHALMUS-MAXIMUS L; FATTY-ACID; LIPID-COMPOSITION; BIOCHEMICAL-COMPOSITION; TROPICAL AQUACULTURE; L LARVAE; NANNOCHLOROPSIS-OCULATA; CHEMICAL-COMPOSITION; Scophthalmus maximus
• Online Access: https://biblio.ugent.be/publication/186102; http://hdl.handle.net/1854/LU-186102; https://doi.org/10.1023/A:1018349131522; https://biblio.ugent.be/publication/186102/file/2108976

The culture of Isochrysis aff. galbana Green (T-ISO) in hatcheries is promoted for its high docosahexaenoic acid (DHA) content which favours the successful rearing of aquatic larvae. In this paper we identified the need for well-defined culture conditions of microalgae if sufficient DHA content is the final goal. Using photoperiods of 24:0 h, 12:12 h, and 16:8 h L/D combined with photon flux densities (PFDs) of 110, 220, and 460 mu E m(-2) s(-1), batch cultures of T-ISO were sampled for DHA content in the exponential as well as the post-exponential (light limited) growth phase. The various light regimes resulted in differences of DHA content of T-ISO revealing influences and strong interactions among the three variables studied. For fast and economic production of T-ISO cells rich in DHA it is recommended to harvest batch cultures at the end of the exponential phase using high photon flux densities (PFDs) under 12:12 h L/D cycles. The same regime or lower PFD under 24:0 h L/D seem to be sufficient for a continuous culture optimization scheme. In any case a strict following of culture protocols is very important since there is evidence for coexistence of different clones within the parental cultures leading to different results depending on which one prevails.