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

•Newly isolated Nostoc sp. was found suitable for phycobiliproteins synthesis.•Effect of Na2CO3 and NaNO3 were studied on phycobiliproteins synthesis.•Effect of initial pH, light, temperature were studied on phycobiliproteins yield.•Induction of phycocyanin in red and phycoerythrin in green light were observed.•Purification and characterization of phycocyanin was carried out. 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 BG110 medium was modified to enhance the biomass productivity in different photobioreactors. The initial pH of 8, light intensity of 40μmolm−2s−1, temperature of 35°C, diurnal cycle of 16:8h (light:dark regime), 75.48μM Na2CO3and 17.65mM 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 0.13gg−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.