Processing-Independent Extracellular Production of High Purity C-Phycocyanin from Spirulina platensis

C-Phycocyanin (C-PC) is a natural blue colored protein of Spirulina platensis. Several methods based on chemical, physical, and enzymatic processes have been reported for the extraction of C-PC. However, most of the processes are either costly and/or time-consuming and/or produce C-PC with less purity. In view of this, a very simple and effective method was developed to extract C-PC with high purity and without involving any energy-consuming process from S. platensis. Wet biomass of S. platensis was harvested and incubated in an optimized 2-(N-morpholino)ethanesulfonic acid buffer with no supplement of any other compounds under dark, anaerobic, and still conditions. These conditions facilitated the leaching out of C-PC from the cells. The purity ratio of the blue color C-PC supernatant obtained was enhanced by precipitation and dialysis. The purity ratio of C-PC produced was 0.644 and increased to 1.345 upon simple dialysis of the crude C-PC. The purity of C-PC was 6.17 upon purifying through column chromatography. Hence, a simple process was developed for producing C-PC of much higher purity than therapeutic grade (>4). Furthermore, the molecular regulation of the extracellular release of C-PC from S. platensis cells was monitored through relative expression levels of alpha and beta subunits of C-PC genes during specific buffer vis-a-vis water as a control. Expression levels of genes encoding alpha and beta subunits of C-PC were found to be upregulated in the case of the 2-(N-morpholino)ethanesulfonic acid buffer treated algal cells compared to water treated algal cells. The higher level expression of these genes documented the higher and specific production of C-PC by the S. platensis upon 2-(N-morpholino)ethanesulfonic acid buffer treatment.