19 Use of Microalgae Pigments in Aquaculture
481
supply for humans, live-stocks and aquaculture. Commercially, astaxanthin is mainly
extracted from H. pluvialis and Chlorella zofingiensis, and cost approximately
USD1900–2000/kg (Yaakob et al. 2014), and it is one of the most available microalgal
pigment worldwide. Subramanian et al. (2013) reported that astaxanthin has effective bio-functionalities approximately 10 times higher than those reported for other
carotenoids such as zeaxanthin, lutein, canthaxanthin and β-carotene due to its high
contents of antioxidants.
Major sources of astaxanthin include artificial synthesis, extraction from shell
animals and production from natural organism such as bacteria, yeast and algae (He
et al. 2007). A basidiomycetous fungi, Xanthophyllomyces dendrorhous, is the only
known fungus that is able to produce astaxanthin as its major carotenoid (Libkind
et al. 2012). Charest et al. (2001) demonstrated that astaxanthin can be extracted from
crawfish shells using supercritical CO 2 with ethanol. In crustaceans, astaxanthin
binds to a specific protein called crustacyanin (CRCN), and it is the interaction
between astaxanthin and CRCN that produces diverse range of colours in the cultured
animals (Wade et al. 2012).
Under natural aquatic environment, microalgae biosynthesize astaxanthin, and
transported along the food chain to zooplankton and larvae of various species of
aquatic animals, which are eventually ingested by fish and other top predators (Ashour
et al. 2018). In aquaculture farms, access to astaxanthin contained natural foods is
limited and thus astaxanthin has to be included in the feeds (Higuera-Ciapara et al.
2006). Domínguez et al. (2005) demonstrated that a live feed rotifer, Brachionus
plicatilis, can accumulate astaxanthin from Hematococcus pluvialis and transfer this
biomolecule to fish larvae.
A green alga, Haematococcus pluvialis, is the highest producer of astaxanthin
to date, exceeding 4% of its dry weight (Boussiba and Vonshak 1991). He et al.
(2007) illustrated that stresses applied in the culture which interfere with cell division such as high light intensity and nutrient (iron, sulfur and phosphate) starvation
could enhance astaxanthin accumulation. However, there are variations of astaxanthin productivity among different species and strains. Allewaert et al. (2017) reported
that different species and strains of H. pluvialis and H. rubicundus had different
astaxanthin production rates.
Although the natural astaxanthin is stronger and safer than the artificial astaxanthin, the supply is still limited. The outdoor mass production is more cost effective, but
there are limitations such as high temperature and the short life span of outdoor photobioreactors. Wan et al. (2014) reported that microalgae produced under controlled
temperature regimes had biomass and astaxanthin production of more than five times
compared to those produced using conventional approaches. In addition to temperature, Zhang et al. (2016) reported that photorespiration played critical roles in astaxanthin production mainly through enhancement of PGA (glycerate-3-phosphate) that
is related to the astaxanthin accumulation in H. pluvialis.
481
supply for humans, live-stocks and aquaculture. Commercially, astaxanthin is mainly
extracted from H. pluvialis and Chlorella zofingiensis, and cost approximately
USD1900–2000/kg (Yaakob et al. 2014), and it is one of the most available microalgal
pigment worldwide. Subramanian et al. (2013) reported that astaxanthin has effective bio-functionalities approximately 10 times higher than those reported for other
carotenoids such as zeaxanthin, lutein, canthaxanthin and β-carotene due to its high
contents of antioxidants.
Major sources of astaxanthin include artificial synthesis, extraction from shell
animals and production from natural organism such as bacteria, yeast and algae (He
et al. 2007). A basidiomycetous fungi, Xanthophyllomyces dendrorhous, is the only
known fungus that is able to produce astaxanthin as its major carotenoid (Libkind
et al. 2012). Charest et al. (2001) demonstrated that astaxanthin can be extracted from
crawfish shells using supercritical CO 2 with ethanol. In crustaceans, astaxanthin
binds to a specific protein called crustacyanin (CRCN), and it is the interaction
between astaxanthin and CRCN that produces diverse range of colours in the cultured
animals (Wade et al. 2012).
Under natural aquatic environment, microalgae biosynthesize astaxanthin, and
transported along the food chain to zooplankton and larvae of various species of
aquatic animals, which are eventually ingested by fish and other top predators (Ashour
et al. 2018). In aquaculture farms, access to astaxanthin contained natural foods is
limited and thus astaxanthin has to be included in the feeds (Higuera-Ciapara et al.
2006). Domínguez et al. (2005) demonstrated that a live feed rotifer, Brachionus
plicatilis, can accumulate astaxanthin from Hematococcus pluvialis and transfer this
biomolecule to fish larvae.
A green alga, Haematococcus pluvialis, is the highest producer of astaxanthin
to date, exceeding 4% of its dry weight (Boussiba and Vonshak 1991). He et al.
(2007) illustrated that stresses applied in the culture which interfere with cell division such as high light intensity and nutrient (iron, sulfur and phosphate) starvation
could enhance astaxanthin accumulation. However, there are variations of astaxanthin productivity among different species and strains. Allewaert et al. (2017) reported
that different species and strains of H. pluvialis and H. rubicundus had different
astaxanthin production rates.
Although the natural astaxanthin is stronger and safer than the artificial astaxanthin, the supply is still limited. The outdoor mass production is more cost effective, but
there are limitations such as high temperature and the short life span of outdoor photobioreactors. Wan et al. (2014) reported that microalgae produced under controlled
temperature regimes had biomass and astaxanthin production of more than five times
compared to those produced using conventional approaches. In addition to temperature, Zhang et al. (2016) reported that photorespiration played critical roles in astaxanthin production mainly through enhancement of PGA (glycerate-3-phosphate) that
is related to the astaxanthin accumulation in H. pluvialis.