Spirulina (Arthrospira platensis) is a planktonic filamentous cyanobacterium, grows easily in media containing inorganic salts with a high concentration of bicarbonate with a pH between 9 and 10. This cyanobacterium is widely used as a health and feed supplement, and as a source of fine chemicals and therefore, it is cultivated in large scale. It is well known that Spirulina is a rich source of the blue pigment cyanobacterial phycocyanin (C-PC) and other water-soluble phycobiliproteins. Research has been initiated to optimize the extraction protocol for C-PC from Spirulina platensis using different buffers of varying pH for maximum pigment yield. The pigment obtained is being investigated for its antibacterial activity and dyeing efficacy to dye different kinds of fabric.