Fractionation of Arthrospira platensis (Spirulina) water soluble proteins by membrane diafiltration

Membrane diafiltration process was developed in order to fractionate the water soluble proteins of the supernatant obtained after Spirulina bead milling disruption and centrifugation. The obtained crude extract was filtered with 50 kDa, 150 kDa, 300 kDa or 0.2 mu m membranes. Phycocyanin purified extracts were produced after filtration on the 300 kDa or 0.2 mu m membranes. The filtration on 0.2 mu m membrane allowed high recovery (more than 89%) of Phycocyanin A and C into the retentate and permeate as well as separation of both molecules (depletion of C-PC into the retentate relatively to the A-PC; enrichment into the permeate). Blue colour permeates, poor in chlorophyll, were successfully produced. Concentrated solutions with more than 80% (dry weight basis) of proteins were obtained. The most severe fouling occurred with the 300 kDa membrane leading to low permeate fluxes (65 L.h(-1).m(-2)). A fractionation of proteins by the size was possible for the 50, 150 and 300 kDa diafiltrations.

Automated summary

Membrane diafiltration process was used to fractionate water soluble proteins from Spirulina, resulting in high purity phycocyanin extracts and production of blue color permeates with low chlorophyll content. High recovery rates and protein concentration were achieved, with successful size-based fractionation of proteins.