- The polyunsaturated fatty acid γ-linolenic acid (GLA, 18:3ω6) is of potential pharmaceutical value. The cyanobacteriumSpirulina platensis could become an excellent source for this fatty acid, provided that GLA content could be increased and a GLA concentrate could be obtained at a low cost. Increasing the cell concentration inSpirulina platensis enhanced the fatty acid content and thus the GLA content. This effect was used to further enhance the GLA content of GLA-overproducing strains. Separation of the galactolipids and their purification via urea complexes formation, resulted in a GLA concentrate of over 90% purity.