Pigments analysis of cyanobacterial strains

Abstract

The pigment variation is specific features among cyanobacteria. The main objective here is the importance of the blue green algae especially because of the pigments present in this class of algae. It is characterized by their specific phycobilin pigments, also other pigments such as chlorophylls and carotenoides are found. Phycobilins are an important group of pigments that through complementary chromatic adaptation optimize the light-harvesting process in phytoplankton cells, exhibiting great potential as cyanobacteria species biomarkers. Cellular chlorophyll concentration is one of the central physiological parameters, routinely followed in many research areas ranging from stress physiology to biotechnology. Carotenoids concentration is often related to cellular stress level; combined pigments assessment provides useful insight into cellular physiological state. So, for analysis of chlorophyll, carotenoids, phycobilins (phycocyanin, allophycocyanin and phycoerythrin) five cyanobacterial strains viz. Anabaena variabilis, Nostoc muscorum, Aulosira fertilissima, Westelliopsis prolifica, and Tolypothrix tenuis were examined. These strains were grown in BG-11medium and their pigments content were analysed at an interval of 7, 14, 21 and 28 days of incubation. Significant differences were observed among the strains with regard to these pigments. Maximum chlorophyll content was observed at 7th day of incubation whereas the other parameters were maximum at 14th day of incubation in all the cases, followed by a gradual decline. Anabaena variabilis showed maximum amount of chlorophyll and phycocyanin whereas Tolypothrix tenuis showed maximum amount of carotenoids, allophycocyanin and phycoerythrin.