Produccion de pigmentos y proteinas de la cianobacteria Anabaena PCC 7120 en relacion a la concentracion de nitrogeno e irradiancia

Abstract

Cyanobacteria of the genus Anabaena produce pigments of commercial value. The present work reports the effect of nitrogen nutrient concentration (0, 1, 2, 4, and 8 mM NaNO3) and irradiance (78, 156 and 238 μmol m -2 s-1) on growth, pigment and protein content in Anabaena PCC 7120 in batch cultures. Growth of the cyanobacterium was little affected by nitrate concentration, with no significant differences between 1 and 8 mM (p< 0,05). However, a concentration of 8 mM gave rise to the highest levels of phycocyanin (174 ± 2 μg ml-1), chlorophyll a (17.4 ± 1.2 μg ml-1), protein (563 ± 2 μg ml -1) and carotenoids (4.5 ± 0.3 μg ml-1). Although cell densities were highest (117 (± 11) x106 cell ml-1) at 78 μmol m-2 s-1, maximum levels of protein and pigments were achieved at 156 μmol m-2 s-1. The number of heterocystes per trichome decreased with increasing nutrient concentration. Biomass production of Anabaena PCC 7120 enriched with phycocyanin, chlorophyll a, and protein was enhanced in a saturating-nutrient medium and a irradiance between 78 and 156 μmol m-2 s -1.