Hyperproduction of phycobiliproteins by the cyanobacterium Anabaena fertilissima PUPCCC 410.5 under optimized culture conditions

Abstract

This study was targeted to find new sources of phycobiliproteins (PBP) as these are important as natural colours, antioxidants and fluorescent markers. Here we report Anabaena fertilissima PUPCCC 410.5 as a good producer of PBP. Control cultures of the cyanobacterium produced 383μg PBP mg−1 dry biomass on day 8. The pH of the medium, supplementation of nitrogen source, sugar and illumination of cultures with different colours of light were optimized for PBP production. Optimized individual parameters were: pH of the medium 7.5; supplementation of 2mmol nitrite L−1 or 0.5% sucrose; and illumination of cultures with blue light. Total PBP production under these conditions ranged between 627 and 696μgmg−1 dry biomass, resulting in nearly 1.6 fold increase, with a significant increase in phycocyanin content. Incubation of 2mmol nitrite L−1 supplemented cultures in blue light resulted in nearly 4.5 fold increase in phycoerythrin compared to the control cultures. The PBP/phycocyanin/phycoerythrin production under the optimized conditions by Anabaena fertilissima PUPCCC 410.5 is significantly higher than the PBP production by the other cyanobacterial strains reported in literature. Thus this cyanobacterial strain is a promising candidate for PBP production at commercial level.