Purification of C-phycocyanin from Spirulina (Arthrospira) fusiformis.

C-phycocyanin was purified from Spirulina (Arthrospira) fusiformis by a multi-step treatment of the crude extract with rivanol in a ratio 10:1 (v/v), followed by 40% saturation with ammonium sulfate. After removal of rivanol by gel-filtration on Sephadex G-25, the pigment solution was saturated to 70% with ammonium sulfate. After the last step of purification, C-phycocyanin had an emission and absorption maxima at 620 and 650 nm, respectively and absorbance ratio A(620)/A(280) of 4.3, which are specific for the pure biliprotein. Its homogeneity was demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, yielding two bands of molecular masses 19500 and 21500 kDa, corresponding to alpha and beta subunits of the pigment, respectively. The yield of C-phycocyanin was approximately 46% from its content in the crude extract.