Development of a new extraction method and functional analysis of phycocyanobilin from unique filamentous cyanobacteria.

As current methods of production of phycocyanobilin, a photosynthetic blue pigment derived from phycocyanin of filamentous cyanobacteria, Pseudanabaena sp. ABRG5-3, Limnothrix sp. SK1-2-1, and Spirulina sp., exhibit a low extraction efficiency, a new extraction method using ethanol extraction as a type of solvolysis with an autoclave (130 ℃, 5.7 bar, 10 min) was developed in this study. This method exhibited high efficiency and enabled easy recovery of the three types of phycocyanobilins. The identity of the three types of phycocyanobilins was confirmed by high-performance liquid chromatography and electrospray ionization-tandem mass spectrometry. Phycocyanobilins were stable at high temperatures (80 ℃) and acidic (pH 3) conditions. Phycocyanobilins also possessed a remarkable antioxidant property. This is the first time that a simple phycocyanobilin extraction method with a recovery rate of more than 60 % and approximately 1 % per dry cell weight of filamentous cyanobacteria has been demonstrated. This novel production method is thus convenient and effective for obtaining high-purity phycocyanobilins.