Extraction, purification and stability of C-phycocyanin from Arthrospira platensis

C-phycocyanin is a highly valuable phycobiliprotein from Arthrospira platensis. However, its extraction, purification and conservation currently limit its commercial use. We review here the most common techniques and less conventional methods. Simple incubation in phosphate buffer at neutral pH can give high yields (> 100 mg/g) and even high protein purity (> 0.7) if the parameters (buffer concentration, temperature, incubation time, Arthrospira platensis. state etc.) are chosen correctly. This method is preferable to incubation in distilled water or acid solutions. Some mechanical, physical or thermal treatments can improve the extraction yield and accelerate the release of C-phycocyanin. Ultrasound-assisted extraction has been widely studied and probes generally give higher extraction yields than baths (> 100 mg/g) in less than 30 min. This technique can be coupled with others, such as freeze–thaw methods, to improve protein release. Indeed, freeze–thaw cycles are an efficient destructuring technique that can be used alone or as a pretreatment. Bead mills or pulsed electric fields can also be used to extract C-phycocyanin, but there is room for improvement in the choice of operating parameters. For purification of the extracted pigments, salting out or aqueous two-phase extraction can be used to increase phycocyanin grade. More advanced purification methods, mostly based on chromatography, can provide addition improvement. C-phycocyanin stability is dependent principally on pH and temperature, and is higher between pH 5 and pH 7 and at temperatures below 40 °C, but the use of various preservatives or conditioning can increases its lifetime.