Purification And Properties Of Phycocyanin From Nostoc Flagelliforme

Phycocyanin is a natural blue pigment present in all blue-green algae. In the living algae cells, phycocyanin can serve as a protein storage unit and as an antioxidant, protecting the cell from certain wavelengths light damage. Moreover, phycocyanin has been shown to have significant anti-tumor properties and it is shown to prevent colitis in an animal model. Phycocyanin has been widely used in such areas as foods, cosmetic and medicine, and it’s no doubt that phycocyanin has a splendid perspective.Five kinds of cell disruption processes were used to disrupt the Nostoc flagelliforme cells, including liquid nitrogen grounding, freezing and thawing, ultrasonic disruption, high-pressure homogenizing, and glass beading treating. As a result, high-pressure homogenizing was most efficient to disrupt cells, freezing and thawing was the most efficient to extract C-phycocyanin from liquid culture N. flagelliforme.In this article, isolation and purification of C-phycocyanin from liquid culture N.flagelliforme were accomplished by DEAE-650M chromatography together with Sephadex G-200chromatography. In DEAE-650M ion exchange chromatography, the volume and concentration of C-phycocyanin sample were30mL and2.34mg/mL, respectively. The C-phycocyanin was eluted by800mL of0.01、0.04、0.1mol/L buffer solution of potassium phosphate at a flow rate of3mL/min. After Sephadex G-200purification, the purity and purification factor were5.321and7.623, respectively. At last, with desaltification and freeze-drying, a commercial product of C-phycocyanin was gained. The absorbance maximum of phycocyanin obtained was620nm by UV/Vis spectrometer. In addition, the fluorescence emission maximum was642nm. Analysis by SDS-PAGE showed that the purified phycocyanin was electrophoretic pure. Moreover, analysis of amino acid composition proved that both phycocyanin and allophycocyanin were ideal protein types. For storage phycocyanin was suitable to store in4℃, natural pH, and avoiding light or weak-light. Low concentration sucrose could enhance its stability.Our methods described here proved applicable in advantages of high activity of protein product, low cost and good repeatability. The results were of fundamental importance for the coming research.