Physicochemical parameters optimization, and purification of phycobiliproteins from the isolated Nostoc sp.

The present study investigated the effects of several physicochemical parameters on the improvement of phycobiliproteins (especially phycocyanin) synthesis in a newly isolated species of Nostoc sp. Standard BG11(0) medium was modified to enhance the biomass productivity in different photobioreactors. The initial pH of 8, light intensity of 40 mu mol m(-2) s(-1), temperature of 35 degrees C, diurnal cycle of 16:8 h (light: dark regime), 75.48 mu M Na(2)CO(3)and 17.65 mM NaNO3 were found most suitable for the phycobiliproteins synthesis. Cyanobacteria exhibited chromatic adaptation, causing overexpression of phycocyanin in red and phycoerythrin in green light. The maximum phycobiliproteins yield of 0.13 g g(-1) dry cell weight was obtained in green light. Phycocyanin was further purified using thin layer chromatography (TLC), anion exchange chromatography and SDS-PAGE (denaturing gel) electrophoresis. (C) 2014 Elsevier Ltd. All rights reserved.