Production, Large-Scale Extraction, and Purification of Phycocyanin by Different Cyanobacteria Isolated from Various Environments

The current research aims to investigate the isolates with the highest phycocyanin yield among five cyanobacterial isolates obtained from the wastewaters of the Porsuk River, thermal springs, and boron-containing waters of Eskişehir province in Türkiye. The study focused on optimization, purification, and characterization to increase phycocyanin yield. Phycocyanin yield was initially analyzed using four extraction methods: freeze-thaw, sonication, homogenization, and treatment with lysozyme. The sonication method determined the thermophilic Geitlerinema sp. as the isolate with the highest phycocyanin yield (116±0.18 mg g-1 C-phycocyanin). The crude extract obtained following optimization studies was first purified by solid ammonium sulfate precipitation/dialysis at 50% and 75% saturation, followed by ion-exchange chromatography using two anionic resins (DEAE-cellulose and Q-sepharose). The purity rate determined in the spectrum was recorded as 4.12 with 48.9% recovery (A620/A280). Characterization using the SDS-PAGE method found molecular weights of 17 kDa and 19 kDa for subunit α and subunit β, respectively. Additionally, we evaluated the stability of the purified thermal phycocyanin at different temperatures, with the pigment displaying resistance to high temperatures up to 60°C, as shown by its CR value.