Aqueous two phase extraction for purification of C-phycocyanin

Aqueous two phase extraction is employed for the purification of C-phycocyanin from Spirulina platensis. A systematic approach is suggested to arrive at the optimal process parameters of aqueous two phase extraction by considering a case study of C-phycocyanin. The influence of various process parameters such as type of aqueous two phase systems, phase forming salt, molecular weight of the phase forming polymer, system pH, phase composition, phase volume ratio, and type and concentration of neutral salts on differential partitioning of C-phycocyanin is evaluated. Desirable conditions for the purification of C-phycocyanin are found in polymer–salt systems especially in polyethylene glycol (4000)/potassium phosphate system. Increase in purity of C-phycocyanin to 3.52 from initial purity of 1.18 is achieved at pH 6, tie line length of 35.53% with a phase volume ratio of 0.8 in a single step of aqueous two phase extraction. Multiple extractions resulted in further increase in purity of C-phycocyanin without loosing the yield and a maximum purity of 4.05 is achieved in third aqueous two phase extraction. The integration of ultrafiltration with aqueous two phase extraction facilitated the selective removal of polyethylene glycol from the purified C-phycocyanin. Finally, C-phycocyanin is freeze dried to obtain in powder form.