72
S. Kato and T. Shinomura
4.4 Carotenogenesis of Algae in Response
to Environmental Stimuli
4.4.1 Light-Induced Carotenoid Accumulation
Light is one of the most striking environmental cues that can induce and alter the
carotenogenesis in algae as well as land plants. To avoid excess photochemical
reaction in photosystem of chloroplast, photosynthetic organisms tightly control the
biosynthesis of photosynthetic pigments in response to light environment.
When grown under circadian light/dark cycle, algal cells show periodic changes
in the cell division rate, photosynthetic activity, expression of photosynthetic apparatus genes, and contents of chlorophylls and carotenoids (Goto and Johnson 1995;
Monnier et al. 2010; Sorek et al. 2013; Miyagishima et al. 2014). Fábregas et al.
(2002) observed that, when a marine alga Nannochloropsis gaditana was grown under
a 12 h/12 h light/dark cycle, the cellular content of chlorophyll a and carotenoids
increased during the light phase and reached the peak at the end of the light
period. Sorek et al. (2013) reported that a coral symbiotic dinoflagellate Symbiodinium sp. exhibited diel fluctuations of concentrations of peridinin, diatoxanthin,
and diadinoxanthin in free-living cells under a light/dark cycle (12 L/12 D).
High-intensity light can induce the biosynthesis and accumulation of carotenoids
in certain algae such as Chlorella zofingiensis, Dunaliella spp., Haematococcus pluvialis, and Euglena gracilis. Li et al. (2009) reported that illumination at 150 μmol
photon m
−2 s
−1 caused 5.3-, 2.2-, and 2.8-fold increases in the content of zeaxanthin, canthaxanthin, and astaxanthin, respectively, in C. zofingiensis compared with
those in the cells grown under 30 μmol photon m
−2 s
−1 . When grown under highintensity light at 460 and 920 μmol photon m
−2 s
−1 , C. zofingiensis cells showed a
3-fold higher astaxanthin content than that in cells grown at 90 μmol photon m
−2 s
−1
(0.04 pg cell
−1 ) (Campo et al. 2004). In Dunaliella salina, a shift of light intensity
from 200 to 1400 μmol photon m
−2 s
−1 increased the intracellular concentration
of β-carotene 7.6-fold accompanied by a cell volume increase (Lamers et al. 2010).
Lamers et al. (2010) reported that the production of β-carotene in D. salina was immediately induced within a day in response to a stepwise increase in light intensity in a
range from 150 to 650 μmol photon m
−2 s
−1 .
H. pluvialis accumulates ketocarotenoid astaxanthin in the cytoplasm of motile
vegetative cells and cyst cells under intense light conditions. Lv et al. (2016) reported
that 80 μmol photon m
−2 s
−1 illumination caused 8.5- and 14.6-fold increases in
the content of total carotenoids and astaxanthin, respectively, on dry weight basis.
Steinbrenner and Linden (2001) showed that continuous illumination at 125 μmol
photon m
−2 s
−1 for 72 h caused astaxanthin accumulation of approximately 6 mg g
−1
dry weight. Similarly, Wang et al. (2003) reported that illumination at 350 μmol
photon m
−2 s
−1 induced the accumulation of astaxanthin-rich lipid globules in the
cytoplasm of H. pluvialis and increased the cellular carotenoid content from 13 to
98 pg cell
−1 , yielding red cell cultures. When H. pluvialis cells were grown under
illumination at a range of 10–250 μmol photon m
−2 s
−1 , higher light intensity induced
S. Kato and T. Shinomura
4.4 Carotenogenesis of Algae in Response
to Environmental Stimuli
4.4.1 Light-Induced Carotenoid Accumulation
Light is one of the most striking environmental cues that can induce and alter the
carotenogenesis in algae as well as land plants. To avoid excess photochemical
reaction in photosystem of chloroplast, photosynthetic organisms tightly control the
biosynthesis of photosynthetic pigments in response to light environment.
When grown under circadian light/dark cycle, algal cells show periodic changes
in the cell division rate, photosynthetic activity, expression of photosynthetic apparatus genes, and contents of chlorophylls and carotenoids (Goto and Johnson 1995;
Monnier et al. 2010; Sorek et al. 2013; Miyagishima et al. 2014). Fábregas et al.
(2002) observed that, when a marine alga Nannochloropsis gaditana was grown under
a 12 h/12 h light/dark cycle, the cellular content of chlorophyll a and carotenoids
increased during the light phase and reached the peak at the end of the light
period. Sorek et al. (2013) reported that a coral symbiotic dinoflagellate Symbiodinium sp. exhibited diel fluctuations of concentrations of peridinin, diatoxanthin,
and diadinoxanthin in free-living cells under a light/dark cycle (12 L/12 D).
High-intensity light can induce the biosynthesis and accumulation of carotenoids
in certain algae such as Chlorella zofingiensis, Dunaliella spp., Haematococcus pluvialis, and Euglena gracilis. Li et al. (2009) reported that illumination at 150 μmol
photon m
−2 s
−1 caused 5.3-, 2.2-, and 2.8-fold increases in the content of zeaxanthin, canthaxanthin, and astaxanthin, respectively, in C. zofingiensis compared with
those in the cells grown under 30 μmol photon m
−2 s
−1 . When grown under highintensity light at 460 and 920 μmol photon m
−2 s
−1 , C. zofingiensis cells showed a
3-fold higher astaxanthin content than that in cells grown at 90 μmol photon m
−2 s
−1
(0.04 pg cell
−1 ) (Campo et al. 2004). In Dunaliella salina, a shift of light intensity
from 200 to 1400 μmol photon m
−2 s
−1 increased the intracellular concentration
of β-carotene 7.6-fold accompanied by a cell volume increase (Lamers et al. 2010).
Lamers et al. (2010) reported that the production of β-carotene in D. salina was immediately induced within a day in response to a stepwise increase in light intensity in a
range from 150 to 650 μmol photon m
−2 s
−1 .
H. pluvialis accumulates ketocarotenoid astaxanthin in the cytoplasm of motile
vegetative cells and cyst cells under intense light conditions. Lv et al. (2016) reported
that 80 μmol photon m
−2 s
−1 illumination caused 8.5- and 14.6-fold increases in
the content of total carotenoids and astaxanthin, respectively, on dry weight basis.
Steinbrenner and Linden (2001) showed that continuous illumination at 125 μmol
photon m
−2 s
−1 for 72 h caused astaxanthin accumulation of approximately 6 mg g
−1
dry weight. Similarly, Wang et al. (2003) reported that illumination at 350 μmol
photon m
−2 s
−1 induced the accumulation of astaxanthin-rich lipid globules in the
cytoplasm of H. pluvialis and increased the cellular carotenoid content from 13 to
98 pg cell
−1 , yielding red cell cultures. When H. pluvialis cells were grown under
illumination at a range of 10–250 μmol photon m
−2 s
−1 , higher light intensity induced