5 Carotenoid Overproduction in Microalgae: Biochemical …
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searched (Fernández-Sevilla et al. 2010) and microalgae emerged as organisms with
a very high potential. In addition to the primary carotenoids they synthesize for
photosynthesis, microalgae are also able to produce secondary carotenoids under
stress conditions (Table 5.2). Indeed, with the development of molecular engineering,
the idea that microalgae constitute the next platform organisms for the production of
high value molecules has emerged (Levitan et al. 2014).
The use of carotenoids is continuously increasing boosting the carotenoid market.
It was estimated to be ~1.24 billion USD in 2016, and is projected to increase
to ~1.53 billion USD by 2021, at a compound annual growth rate (CAGR) of
3.78% from 2016 to 2021 (http://www.bccresearch.com) (Liu et al. 2014, Ambati
et al. 2019) (Fig. 5.1a). The markets for each carotenoid has no equivalent. As
displayed in Fig. 5.1b, the most important are those related to astaxanthin (3,3’dihydroxy-β,β-carotene-4,4’-dione), lutein (β,ε-carotene-3,3’-diol) and β-carotene
(β,β-carotene). The total production of natural carotenoids (with major carotenoids
including fucoxanthin, lutein, violaxanthin and neoxanthin) has been estimated as
100 million tons/year (Delgado-Vargas et al. 2000). The amount of publications
about all the aspects related to carotenoids is yearly increasing (Fig. 5.2) reaching
more than 14,000 publications listed in the Web of Science. Therefore, the writing
of this chapter was not possible without making chooses and we apologize to the
colleagues whose data of interests are not cited in this contribution. We tried to focus
the selection of data on the most recent ones in order to show that the production
of carotenoids by microalgae is a tailor-made process that should take into account
biological factors such as the taxon (origin and the genome composition) but also
the factors related to the environment such as temperature, light quality and quantity,
salinity etc. but also rely on general biological responses to stress.
5.2 The Best Alga for the Highest Carotenoid Production:
Does the Taxon Matter?
When reviewing literature, it appears clearly that the carotenoid production capacity
is (at least) strain dependent (Table 5.3). For instance, Xu and Harvey (2019) reported
that the total carotenoids accumulated by several strains of Dunaliella grown under
red light varied from 1 to 3 according to the strain considered. In another study, 15
strains of chlorophycean microalgae were screened for the capacity of lutein production (Del Campo et al. 2000). Because tens of thousands microalga taxa have been
described (Guiry 2012), and new species are continuously described (e.g. Schoefs
et al. (2020)), exploring the biodiversity looks to be a promising strategy for finding
putative new taxon with either a unique carotenoid composition or productivity. This
requires quick and precise tools not only for estimating the classification of the alga
but also the amount of pigments. Carotenoid diversity and sometimes specific distribution in the different taxonomic branches (Table 5.4) offers the possibility to use the
pigment composition for chemotaxonomic through a multivariate analysis (Paliwal
83
searched (Fernández-Sevilla et al. 2010) and microalgae emerged as organisms with
a very high potential. In addition to the primary carotenoids they synthesize for
photosynthesis, microalgae are also able to produce secondary carotenoids under
stress conditions (Table 5.2). Indeed, with the development of molecular engineering,
the idea that microalgae constitute the next platform organisms for the production of
high value molecules has emerged (Levitan et al. 2014).
The use of carotenoids is continuously increasing boosting the carotenoid market.
It was estimated to be ~1.24 billion USD in 2016, and is projected to increase
to ~1.53 billion USD by 2021, at a compound annual growth rate (CAGR) of
3.78% from 2016 to 2021 (http://www.bccresearch.com) (Liu et al. 2014, Ambati
et al. 2019) (Fig. 5.1a). The markets for each carotenoid has no equivalent. As
displayed in Fig. 5.1b, the most important are those related to astaxanthin (3,3’dihydroxy-β,β-carotene-4,4’-dione), lutein (β,ε-carotene-3,3’-diol) and β-carotene
(β,β-carotene). The total production of natural carotenoids (with major carotenoids
including fucoxanthin, lutein, violaxanthin and neoxanthin) has been estimated as
100 million tons/year (Delgado-Vargas et al. 2000). The amount of publications
about all the aspects related to carotenoids is yearly increasing (Fig. 5.2) reaching
more than 14,000 publications listed in the Web of Science. Therefore, the writing
of this chapter was not possible without making chooses and we apologize to the
colleagues whose data of interests are not cited in this contribution. We tried to focus
the selection of data on the most recent ones in order to show that the production
of carotenoids by microalgae is a tailor-made process that should take into account
biological factors such as the taxon (origin and the genome composition) but also
the factors related to the environment such as temperature, light quality and quantity,
salinity etc. but also rely on general biological responses to stress.
5.2 The Best Alga for the Highest Carotenoid Production:
Does the Taxon Matter?
When reviewing literature, it appears clearly that the carotenoid production capacity
is (at least) strain dependent (Table 5.3). For instance, Xu and Harvey (2019) reported
that the total carotenoids accumulated by several strains of Dunaliella grown under
red light varied from 1 to 3 according to the strain considered. In another study, 15
strains of chlorophycean microalgae were screened for the capacity of lutein production (Del Campo et al. 2000). Because tens of thousands microalga taxa have been
described (Guiry 2012), and new species are continuously described (e.g. Schoefs
et al. (2020)), exploring the biodiversity looks to be a promising strategy for finding
putative new taxon with either a unique carotenoid composition or productivity. This
requires quick and precise tools not only for estimating the classification of the alga
but also the amount of pigments. Carotenoid diversity and sometimes specific distribution in the different taxonomic branches (Table 5.4) offers the possibility to use the
pigment composition for chemotaxonomic through a multivariate analysis (Paliwal