Increasing γ-linolenic acid content in Spirulina platensis using fatty acid supplement and light-dark illumination

Abstract

Spirulina platensis, a filamentous cyanobacterium, produces γ-linolenic acid (GLA, 18:3), which is an important anti-inflammatory for pharmaceutical use. Thus, to increase the GLA content in S. platensis, this study investigated the combined effect of a light-dark (LD) two-stage culture and mixotrophic culture including a precursor of GLA. When compared with a photoautotrophic culture, the supplement of a GLA precursor, such as a long- or short-chain carbon source, enhanced the total fatty acid and GLA contents in the cells in the two-stage culture. The highest GLA content of 2% (w/w) and productivity of 27. 6 ± 4. 7 mg L -1 were obtained in S. platensis when using 0. 01 mM palmitic acid as a supplement in the two-stage culture. This study also suggests that a mixotrophic and LD two-stage culture may represent a method for increasing the total lipid production, which can then be converted to biofuels.