Seawater-cultured Spirulina subsalsa as a more promising host for phycocyanin production than Arthrospira platensis

C-phycocyanin produced from Arthrospira platensis is of great commercial interest in healthcare industries but adoption is challenged by low quality and productivity. To find a high-quality alternative to Arthrospira platensis, this study compares C-phycocyanin production by Spirulina subsalsa and Arthrospira platensis in chemically defined freshwater medium and seawater with added monosodium glutamate residue. In the two media, Spirulina subsalsa showed higher content and first-extraction efficiency of C-phycocyanin than Arthrospira platensis did. Absorption maxima in red and blue spectral regions were observed for the first time to shift toward longer wavelengths for methanolic extracts of the cyanobacteria grown in seawater. Tightly coiled Spirulina subsalsa remained unaffected and exhibited stronger adaptation in a seawater environment than loosely spiralled Arthrospira platensis. These results preliminarily demonstrate the feasibility of cultivating Spirulina subsalsa in seawater with low-cost nutrient supplements as a promising candidate to produce C-phycocyanin as well as to reduce nutritional and freshwater investments. Overall, more research can be performed redarding culture conditions and extraction process to optimize C-phycocyanin production and extraction.