A novel two-stage culture strategy to enhance the C-phycocyanin productivity and purity of Arthrospira platensis

The inconsistent light intensity requirements for C-phycocyanin accumulation and algal growth have greatly hampered the productivity and quality of this high-value pigment protein. This study aimed to improve both the production efficiency and extract quality of C-phycocyanin in the cyanobacterium Arthrospira platensis HN5, by adjusting light intensity and nitrogen supply at different cultivation stages. We established an optimized twostage culture strategy consisting of a 4-d phase for algal growth under 320 & mu;mol m- 2 s- 1 and a subsequent 2d period using 160 & mu;mol m- 2 s- 1 illumination and NaNO3 supplement to promote C-phycocyanin accumulation. By adopting this strategy, up to 18.86% content and 59.72 mg L-1 d-1 productivity of C-phycocyanin were obtained. Our results indicate that the increased C-phycocyanin content improved the quality of C-phycocyanin extract, and reactive grade C-phycocyanin (A620/A280 = 3.16) was recovered through a one-step ammonium sulfate precipitation. The established two-stage culture strategy, as illustrated herein, could be a highly promising strategy for improving the content and productivity of C-phycocyanin and effectively enhancing the quality of C-phycocyanin products, which could be particularly conducive to the large-scale development of this algal pigment in the food industry sector.