Use of continuous culture to develop an economical medium for the mass production of Isochrysis galbana for aquaculture

摘要

The purpose of this study was to develop an economical agricultural fertilizer-based medium for the mass production of Isochrysis galbana Parke, a marine microalga producing docosahexaenoic acid (DHA) and considered an excellent feed for use in aquaculture. Different fertilizers were used to replace the main nutrients, nitrogen and phosphorus, and the micronutrients of the well-known commercial medium, ALGAL. The obtained results showed that I. galbana preferred nitrate, instead of ammonium, as the nitrogen source and phosphate as the phosphorus source. Nonetheless, a nitrate concentration above 4 mM inhibited cell growth. The alternative medium proposed achieved a biomass productivity 22% higher than that for the ALGAL medium, reducing the medium's contribution to the overall biomass cost by over 95%, with protein, lipid, carbohydrate, and DHA contents at 44, 36, 25, and 1.47% of dry weight, respectively, thus providing a cheaper biomass with excellent nutritional value for use in aquaculture.