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 percent NaCl, and the lowest 15 micrograms l-1 day-1, in CONC-006 at 30 percent 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 percent) 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 percent NaCl, and in PES, 0.53 div day-1 at 5 percent NaCl. According to these results, the best integration of growth and carotenogenesis in CONC-007 was obtained at 15 percent NaCl in J/1 from 10 to 25 percent NaCl in PES and in CONC-006, from 5 to 20 percent NaCl in J/1 and from 5 to 10 percent NaCl in PES