Purification of phycocyanin from isolated and identified hot spring cyanobacteria

ABSTRACT

Phycocyanin is a phycobiliprotein used as a healthy food additive as well as an ingredient in cosmetic dye preparation. In this study, we attempted molecular and morphological identification of three thermophilic filamentous cyanobacteria and also explored a method to separate and purify thermostable C-phycocyanin of analytical grade from them for biotechnological applications. Cyanobacteria strains were collected from hot springs in Karakoc-Seferihisar, Gulbahce-Urla and Sifne-Cesme in Izmir, Turkey. The samples were identified both by morphological observations and genetic assay. Filamentous cyanobacteria DNA from the collected samples was isolated and extracted, and were analyzed using a 16S rRNA cyanobacteria-specific PCR and a denaturing-gradient gel electrophoresis (DGGE). Extraction and purification of phycocyanin was performed in two stages, ammonium sulfate saturation and dialysis, gel filtration and ion exchange chromatography. Conventional separation of Geitlerinema sp., Halospirulina sp. and Phormidium animale was successfully performed yielding C-phycocyanin at 493.760±3.610, 89.060±3.209, 32.978±0.350, 4.046±0.193, 8.303±0.511 and 4.196±0.090 mg/g purity from gel filtration and ion exchange chromatography processes, respectively. The SDS-PAGE demonstrated that the P. animale, Halospirulina sp. and Geitlerinema sp. were purified phycocyanin. Overall, in this study, three cyanobacteria were isolated and cultivated in a laboratory conditions, and then the cyanobacterial cells was extracted and purified thermostable C-phycocyanin obtained, which may be used as raw material in food supplement and pharmaceutical industry.