The influence of nutrient manipulation on growth and cultivation constituents of Anabaena variabilis

Abstract

The cyanobacterium identified as Anabaena variabilis is a filamentous cyanobacterium that is capable of differentiating specialized cells, the heterocysts and akinetes, to survive under different stress conditions. The objective of the present study is to investigate the impact of abiotic stresses, namely nitrogen (N), phosphorus (P), and sulphur (S), on the axenic culture of Anabaena variabilis and its production of pigments such as chl a and carotenoids, as well as metabolites like proteins, carbohydrates, phenols, and flavonoids. The growth rate was evaluated using optical density (OD)750 nm, and the nutrient supplementation of nitrogen (N), phosphorus (P), and sulphur (S) at 2.5 g/L, 0.06 g/L, and 0,095g/L, respectively, resulted in the highest algal dry weight and maximum production of pigments and biochemical productivity. This demonstrated that the composition of the culture constituents changes as a result of the growth of A. variabilis when exposed to different nutritional compositions.