Producción de Astaxantina y expresión de genes en Haematococcus pluvialis (Chlorophyceae, Volvocales) bajo condiciones de estrés por deficiencia de nitrógeno y alta irradiancia: Producción de astaxantina y expresión de genes en H. pluvialis

Abstract

Astaxanthin is an antioxidant carotenoid used in cosmetic, pharmaceutic and food industries that is produced by microalgae H. pluvialis in natural form; it is a secondary metabolite that increases production when microalgae grows under stress conditions, like food deficiency and high irradiation, among others. The goal of this research was to test microalgae growing under nitrogen deficiency conditions in a concentration of 4.0-5.0% and evaluate astaxanthin production and gene expression in dye biosynthesis. For this purpose, a culture in rm medium was carried out with 4.0 and 5.0% nitrogen, using the following conditions: pH 6.7; light/dark cycle 20h: 4h; temperature 25 oC; continuous agitation; 5% CO2; lighting with white fluorescent lamps (Tlt 20w/54rs Philips brand); and a high irradiance of 140 μE. The growth in the medium was used as a control with nitrogen in normal concentrations during 36 days (under the same conditions). Sampling was carried out every third day for quantification of astaxanthin and chlorophyll and the determination of gene expression. The anova performed established that there are no significant differences between treatments (P = 0.053). However, astaxanthin production with a nitrogen concentration of 4.0% and a high irradiance of 140 μE was 3.52x10-6 μg cell-1 x mL-1, increased by 40% when compared to that obtained with 5.0% nitrogen (2.08x10-6 ug cell-1 x mL-1). The psy, pds, lcy, bkt and chy genes were expressed with 4.0% nitrogen, while 5.0% nitrogen only allowed psy, pds and chy.