Effect of the phosphate concentrations on the efficiency of phycocyanin extraction from Arthrospira (Spirulina)

Phycocyanin (PC) has many potential health benefits, such as supporting the immune system, acting as an antioxidant, and having anti-inflammatory properties, etc. The objective of this work was to investigate the efficiency of phycocyanin extraction using different phosphate buffer concentrations (0-100 mM) with two groups of Arthrospira (Spirulina) materials: group 1 (PC content < 15% of dry weight, dw.) and group 2 (PC content >15% dw.). The results showed that the concentration of the phosphate buffer did not affect the efficiency of phycocyanin extraction for group 1 material. However, the efficiency of phycocyanin extraction, as indicated by PC concentration, purity ratio, PC content in the extract, yield, and percentage of recovery, significantly increased for group 2 material when the concentration of the phosphate buffer was increased. The yield of PC extract was approximately 9-13% dw. for group 1 and 7-22% dw. for group 2 material, respectively. The PC recovery of group 1 was approximately 72-91% of the initial content, whereas, the recovery of group 2 was less than 70% when extracted with 10 mM phosphate buffer. However, repeating the extraction process twice increased the recovery of group 2 to 78-85%, resulting in an enhance yield of the extract. Additionally, the use of 10 mM phosphate buffer reduced the production cost and the remaining phosphate in the extract by around 28% and 10-fold, respectively, compared to using 100 mM. Therefore, 10 mM phosphate buffer was considered a suitable concentration for phycocyanin extraction.