Photoinduction of Massive β-Carotene Accumulation by the Alga Dunaliella bardawil

Abstract

The massive accumulation of j#-carotene by the halotolerant micro alga Dunaliella bardawil, in response to high light intensity and several other environmental factors, has been studied so far under different sets of fixed conditions. To determine the kinetics and characteristics of the induction of

Low-temperature-induced β-carotene and fatty acid synthesis, and ultrastructural reorganization of the chloroplast inDunaliella salina(Chlorophyta)

“…However, in D. salina cells grown under suboptimal temperature the thylakoids occupy only a small part of the stroma and there is an increase in the number of lipid-carotene globules in the periphery of the chloroplast. Similar effects have been observed in the chloroplast of D. bardatoiI by Ben-Amotz & Avron (1982) and by Lers et al (1990), although in this case carotene-rich globules were induced by transferring algal cells from low to high light intensity at optimal temperatures for growth. The appearance of lipid globules in D. salina cells suggests the possibility that the induction of carotenogenesis is correlated to lipid accumulation under suboptimal temperature for growth.…”

“…The extent of this accumulation is a direct function of the amount of light to which algae are exposed during a division cycle (Ben-Amotz et al, 1982;Ben-Amotz & Avron, 1983). Maximal concentrations of d-carotene were found in D. bardawil and D. salina cells exposed to a high light intensity and high concentrations of NaCl (4-5"5 M) and grown under nitrogen-limiting conditions (Semenenko & Abdullaev, 1980;Ben-Amotz et al, 1987;Lers et al, 1990). The amount of d-carotene was also dependent on the spectral composition of the light.…”

Effect of growth arrest on carotene accumulation and photosynthesis in Dunaliella

“…In conditions has been reported previously, for example after transfer from low-light to high-light (Lers et al, 1990) or low-salt to high-salt conditions (G6mez-Pinchetti et a Borowitzka e t al., 1990). In the D. bardawil strain used here, the levels of a-carotene were extremely low, in contrast to studies by other groups reporting acarotene levels of 2.5% or higher (Ben-Amotz e t Erazo e t al., 1989).…”

Growth and Carotenoid Production in Dunaliella spp. Isolated from Hypersaline Habitats in the Region of Essaouira (Morocco): Effect of NaNO3 Concentration

“…Indeed, it is well known that when some Dunaliella species or strains are submitted to environmental stress conditions as high salt concentrations, high light intensities or nutrient deprivation, these organisms can overproduce and accumulate very large amounts of β-carotene [39][40][41][42][43][44].…”