title: Purification of the photosynthetic pigment C-phycocyanin from heterotrophic Galdieria sulphuraria.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors: Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmsvej 49, DK-9000 Aalborg, Denmark.
authors: Laila
authors: L
authors: Sørensen
authors: Andrea
authors: A
authors: Hantke
authors: Niels T
authors: NT
authors: Eriksen
mesh_terms: D020418:Algal Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification*; D000837:Anion Exchange Resins; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D005591:Chemical Fractionation; D002851:Chromatography, High Pressure Liquid; D004396:Coloring Agents / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D003358:Cosmetics / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D000458:Cyanobacteria / Q000254:growth & development / Q000378:metabolism; D019587:Dietary Supplements; D004591:Electrophoresis, Polyacrylamide Gel; D005505:Food Coloring Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D052836:Heterotrophic Processes; D008164:Luminescent Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification*; D008970:Molecular Weight; D010798:Phycocyanin / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification*; D020836:Protein Structure, Quaternary; D021122:Protein Subunits; D000461:Rhodophyta / Q000254:growth & development / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D014462:Ultrafiltration
chemical_list: D020418:Algal Proteins; D000837:Anion Exchange Resins; D001426:Bacterial Proteins; D004396:Coloring Agents; D003358:Cosmetics; D005505:Food Coloring Agents; D008164:Luminescent Proteins; D021122:Protein Subunits; D010798:Phycocyanin
keywords: ammonium sulfate fractionation; anion exchange chromatography; aqueous two-phase extraction; phycocyanin, purity number; ultrafiltration