Resumen

LEMUS, Nathalie et al. Growth and biochemical composition of Limnothrix sp. at different salinities and concentrations of nitrate. Rev. colomb. biotecnol [online]. 2013, vol.15, n.1, pp.159-166. ISSN 0123-3475.

In this research we evaluate the effect of salinity (15, 25 and 35 UPS) and nitrate concentration (4, 8 and 16 mmoles L^-1) on growth and biochemical composition of the cyanobacterium Limnothrix sp. (LAEP-52) with a view to exploitation for biotechnological purposes. The cyanobacterium was grown in volumes of 1 L for 20 days. The culture conditions included 25 °C, irradiance of 98 µmol m^-2 s^-1, photoperiod 12:12 and continuous aeration (200 mL min^-1). Growth was evaluated every 48 hours through the measurement of optical density at 730 nm. It showed that salinity and concentration of nitrate modulate the growth and biochemical composition of Limnothrix sp. The highest values of growth (6.3 ± 0.38 mg mL^-1), protein content (57 ± 4.56%), phycocyanin (170.3 ± 13.6 mg mL^-1) and chlorophyll a (16 ± 1.28 mg mL^-1) were obtained at the lowest salinity (15 UPS) and highest levels of nitrate (16 mmolesL^-1). By contrast, higher concentrations of lipids (21.3 ± 1.19%), carbohydrate (14.47 ± 1.15%) and carotenoids (6 ± 0.48 mg mL^-1) were achieved in the highest salinity (35 UPS) and the lowest concentrations of nitrate (4 mmoles L^-1). The production of exopolysaccharides was only influenced by salinity, reaching its highest values at 35 UPS (1600 ± 112.25 mg L^-1). The content of proteins, lipids, carbohydrates and pigments obtained in this cyanobacterium allow cataloged as an organism which can be used in biotechnology industries, either as feed for farmed organisms or as a source of metabolites of industrial interest.

Palabras clave : cyanobacteria; biotechnology; Limnothrix.

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