Exploring Porphyridium purpureum and Porphyridium aerugineum as alternative resources for phycobiliprotein production.

Microalgae not only fix carbon dioxide, but also represent a promising alternative resource for the production of proteins, lipids, and polysaccharides. This study employed two Porphyridium strains to compare their responses under different light qualities. P. purpureum up-regulated the content (up to 69.37 ± 0.92 mg/g DW) and proportion of phycoerythrin to enhance light absorption, which led to the accumulation of total soluble proteins, neutral lipids and exopolysaccharides under blue light. In contrast, P. aerugineum primarily improved the light energy utilization by increasing phycocyanin levels (up to 81.10 ± 0.60 mg/g DW), resulting in the degradation of neutral lipids and the accumulation of exopolysaccharides. Given the biomass, the highest yields of phycoerythrin (169.61 ± 2.90 mg/L) and phycocyanin (216.92 ± 1.90 mg/L) were achieved by P. purpureum and P. aerugineum cultured under white light, respectively. These findings indicate that Porphyridium can serve as a valuable resource for phycobiliprotein production, with biomolecules synthesis being tightly regulated by light quality.