The effect of salinity on the growth and carotenogenesis in two Chilean strains of Dunaliella salina Teodoresco.

Abstract

We studied the effect of salt concentration on the growth and carotenogenesis in two Chilean strains of Dunaliella salina, CONC-006 and CONC-007, cultivated in two media of different chemical composition J/l and PES, under controlled laboratory conditions. Growth rates, k (div day-1), intrinsic production rates of total carotenoids per unit time rcar (day-1), maximum levels of total carotenoids, K (mg l-1), and maximum production of total carotenoids per unit time, rK/4 (micrograms l-1 day-1) were estimated from growth and carotenogenesis data. The highest maximum productivity of total carotenoids was 978 micrograms l-1 day-1 obtained in CONC-007 at 25% NaCl, and the lowest 15 micrograms l-1 day-1, in CONC-006 at 30% NaCl, both growing in PES medium. CONC-007 showed the highest growth rates, 0.76 and 0.65 div day-1, at the lowest salt concentration (5%) in PES and J/1, respectively. On the contrary, the strain CONC-006 exhibited a different growth pattern in both media. Its maximum growth rate in J/1 was 0.37 div day-1 at 20% NaCl, and in PES, 0.53 div day-1 at 5% NaCl. According to these results, the best integration of growth and carotenogenesis in CONC-007 was obtained at 15% NaCl in J/1 from 10 to 25% NaCl in PES and in CONC-006, from 5 to 20% NaCl in J/1 and from 5 to 10% NaCl in PES.