title: Stable isolation of phycocyanin from Spirulina platensis associated with high-pressure extraction process.
abstract: A method for stably purifying a functional dye, phycocyanin from  Spirulina platensis was developed by a hexane extraction process combined with high pressure. This was necessary because this dye is known to be very unstable during normal extraction processes. The purification yield of this method was estimated as 10.2%, whose value is 3%-5% higher than is the case from another conventional separation method using phosphate buffer. The isolated phycocyanin from this process also showed the highest purity of 0.909 based on absorbance of 2.104 at 280 nm and 1.912 at 620 nm. Two subunits of phycocyanin namely α-phycocyanin (18.4 kDa) and β-phycocyanin (21.3 kDa) were found to remain from the original mixtures after being extracted, based on  SDS-PAGE analysis, clearly demonstrating that this process can stably extract phycocyanin and is not affected by extraction solvent, temperature, etc. The  stability of the extracted phycocyanin was also confirmed by comparing its DPPH  (α,α-diphenyl-β-picrylhydrazyl) scavenging activity, showing 83% removal of oxygen free radicals. This activity was about 15% higher than that of commercially available standard phycocyanin, which implies that the combined extraction method can yield relatively intact chromoprotein through absence of degradation. The results were achieved because the low temperature and high pressure extraction effectively disrupted the cell membrane of Spirulina platensis and degraded less the polypeptide subunits of phycocyanin (which is a temperature/pH-sensitive chromoprotein) as well as increasing the extraction yield.
authors: Department of Medical Biomaterials Engineering, Kangwon National University, Chuncheon 200-701, Korea. hyeonl@seowon.ac.kr.
authors: Yong Chang
authors: YC
authors: Seo
authors: Woo Seok
authors: WS
authors: Choi
authors: Jong Ho
authors: JH
authors: Park
authors: Jin Oh
authors: JO
authors: Park
authors: Kyung-Hwan
authors: KH
authors: Jung
authors: Hyeon Yong
authors: HY
authors: Lee
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification*; D010798:Phycocyanin / Q000737:chemistry / Q000302:isolation & purification*; D011312:Pressure; D053545:Spirulina / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D010798:Phycocyanin