Resumen

LORETO, César; ROSALES, Néstor; BERMUDEZ, José  y  MORALES, Ever. PIGMENT AND PROTEIN PRODUCTION OF THE CYANOBACTERIUM ANABAENA PCC 7120 IN RELATION TO NITROGEN CONCENTRATION AND IRRADIANCE. Gayana Bot. [online]. 2003, vol.60, n.2, pp. 83-89. ISSN 0717-6643.  doi: 10.4067/S0717-66432003000200001.

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

Palabras clave : Chlorophyll a; cyanobacteria; nitrate; nutrients; phycocyanin.