Comparison of different methods for extraction of phycocyanin from the cyanobacterium Arthrospira maxima (Spirulina)

Phycocyanin is an interesting alternative to synthetic food colorants. Various methods to obtain phycocyanin from Arthrospira (Spirulina) biomass have been described in the literature, including ultrasonication, glass bead extraction and freeze-thawing. In this study, three optimized procedures were implemented to assess their efficacy in obtaining phycocyanin from Arthrospira maxima biomass, facilitating a comparative analysis of their effectiveness. After harvesting the biomass, extraction processes were conducted utilizing ultrasonication followed by flocculation with chitosan in various organic acid solutions, as well as glass bead extraction and freeze-thawing techniques, each followed by centrifugation. The obtained extracts were analyzed spectrophotometrically across the wavelength range of 280 to 800 nm. The freeze-thawing method yielded the highest C-PC contents at 17.03 ± 0.53%, followed closely by the ultrasonication method at 15.21 ± 0.41%. The highest purity of 2.02 ± 0.01 was attained through ultrasonication and subsequent flocculation with chitosan in acetic acid. Conversely, employing chitosan dissolved in citric or lactic acid for flocculation resulted in greenish extracts containing high amounts of chlorophyll.