Optimal Renewal Rate and Nutrient Concentration for the Production of the Marine Microalga Phaeodactylum tricornutum in Semicontinuous Cultures.

A factorial experiment comprising six nutrient concentrations and six renewal rates was set to optimize semicontinuous cultures of Phaeodactylum tricornutum. Maximal cell density, 85 x 10(sup6) cells ml(sup-1), was obtained with 8 and 16 mmol of N per liter and a renewal rate of 10%. Protein stabilized at about 60% of the organic fraction for nitrogen-sufficient cultures. Both lipids and carbohydrates were stored as energetic reserves.