Commercial Potential of the Cyanobacterium <i>Arthrospira maxima</i>: Physiological and Biochemical Traits and the Purification of Phycocyanin

Arthrospira maxima is a natural source of fine chemicals for multiple biotechnological applications. We determined the optimal environmental conditions for A. maxima by measuring its relative growth rate (RGR), pigment yield, and photosynthetic performance under different pH and temperature conditions. RGR was highest at pH 7–9 and 30 °C. Chlorophyll a, phycocyanin, maximal quantum yield (Fv/Fm), relative maximal electron transport rate (rETRmax), and effective quantum yield (ΦPSII) were highest at pH 7–8 and 25 °C. Interestingly, phycoerythrin and allophycocyanin content was highest at 15 °C, which may be the lowest optimum temperature reported for phycobiliprotein production in the Arthrospira species. A threestep purification of phycocyanin (PC) by ultrafiltration, ion-exchange chromatography, and gel filtration resulted in a 97.6% purity of PC