Background: The phycobiliprotein C-phycocyanin (C-PC) is used in cosmetics, diagnostics and foods and also as a nutraceutical or biopharmaceutical. It is produced in the cyanobacterium Arthrospira platensis grown phototrophically in open cultures. C-PC may alternatively be produced heterotrophically in the unicellular rhodophyte Galdieria sulphuraria at higher productivities and under improved hygienic standards if it can be purified as efficiently as C-PC from A. platensis.
Results: Ammonium sulfate fractionation, aqueous two-phase extraction, tangential flow ultrafiltration and anion exchange chromatography were evaluated with respect to the purification of C-PC from G. sulphuraria extracts. Galdieria sulphuraria C-PC showed similar properties to those described for cyanobacterial C-PC with respect to separation by all methodologies. The presence of micelles in G. sulphuraria extracts influenced the different procedures. Only chromatography was able to separate C-PC from a second phycobiliprotein, allophycocyanin.
Conclusion: C-PC from heterotrophic G. sulphuraria shows similar properties to cyanobacterial C-PC and can be purified to the same standards, despite initial C-PC concentrations being low and impurity concentrations high in G. sulphuraria extracts.
Keywords: ammonium sulfate fractionation; anion exchange chromatography; aqueous two-phase extraction; phycocyanin, purity number; ultrafiltration.
© 2013 Society of Chemical Industry.