246
M. M. Maroneze et al.
The astaxanthin is formed from the β-carotene by the action of the enzymes BKT or
CrtR-b. The intermediate compounds of catalytic activity are canthaxanthin and zeaxanthin, respectively (Rajesh et al. 2017). Both pathways are reported for microalgae
H. pluvialis. However, the route where β-carotene is converted to canthaxanthin via
echinenone and, after, converted to astaxanthin is the more proposed (Saini et al.
2019; Han et al. 2013; Henríquez et al. 2016).
The phycobilins, in its turn, are biosynthesized from heme by the action of the HOs
enzyme (Mulders et al. 2014). The phycobilins biosynthesis starts from glutamic
acid, which gives rise to ALA. The condensation of two ALA molecules forms
porphobilinogen (PBG). The enzymes HMB synthase and UPG III synthase form
from the PBG the UPG III. The UPG III leads to the formation of protoporphyrin IX
(Chakdar and Pabbi 2016; Saini et al. 2018). The action of the enzyme FeCh catalyzes
the formation of protoheme. Subsequently, the protoheme is converted to biliverdin
IX by the action of the enzyme Hos and from the biliverdin IX phycocyanobilins and
phycoerythrobilin are produced (Manirafasha et al. 2016; Stanic-Vucinic et al. 2018).
For a more detailed panorama of the biosynthesis of carotenoids and phycobilins,
see Fernandes et al. (2017), and Czarnecki and Grimm (2012).
11.4 Chemical Synthesis
In 1950 was described by Karrer and Eugster (1950), Inhoffen et al. (1950), and
Milas et al. (1950), the chemical synthesis of pigments, starting with the synthesis of
β-carotene. The scientific achievements of these three groups were the basis for the
industrial production procedures. In 1954, Hoffmann-La Roche began commercial
production of β-carotene. The method based on the Grignard reaction, which follows
the synthesis principle C19 + C2 + C19, it presented a yield of 60%. In 1960, the
BASF developed a higher yield method (85%) based on Wittig reaction (C20 + C20).
The disadvantage of the Wittig reaction-based process is the undesirable formation of
triphenylphosphine oxide, which needs of recycling due to its low biodegradability
(Ribeiro et al. 2011).
Today, the two largest industrial producers are DSM and BASF, which produce the
β-apo-8’-carotenal, β-carotene, canthaxanthin, astaxanthin, lutein, lycopene, zeaxanthin, and citranaxanthin pigments. Although chemical synthesis is a consolidated
market, it became less desirable, given the awareness of the benefits associated
with natural dyes. In this context, several companies are concentrated on developing methods for producing pigments from photoautotrophic cultures (Cardoso
et al. 2017).
M. M. Maroneze et al.
The astaxanthin is formed from the β-carotene by the action of the enzymes BKT or
CrtR-b. The intermediate compounds of catalytic activity are canthaxanthin and zeaxanthin, respectively (Rajesh et al. 2017). Both pathways are reported for microalgae
H. pluvialis. However, the route where β-carotene is converted to canthaxanthin via
echinenone and, after, converted to astaxanthin is the more proposed (Saini et al.
2019; Han et al. 2013; Henríquez et al. 2016).
The phycobilins, in its turn, are biosynthesized from heme by the action of the HOs
enzyme (Mulders et al. 2014). The phycobilins biosynthesis starts from glutamic
acid, which gives rise to ALA. The condensation of two ALA molecules forms
porphobilinogen (PBG). The enzymes HMB synthase and UPG III synthase form
from the PBG the UPG III. The UPG III leads to the formation of protoporphyrin IX
(Chakdar and Pabbi 2016; Saini et al. 2018). The action of the enzyme FeCh catalyzes
the formation of protoheme. Subsequently, the protoheme is converted to biliverdin
IX by the action of the enzyme Hos and from the biliverdin IX phycocyanobilins and
phycoerythrobilin are produced (Manirafasha et al. 2016; Stanic-Vucinic et al. 2018).
For a more detailed panorama of the biosynthesis of carotenoids and phycobilins,
see Fernandes et al. (2017), and Czarnecki and Grimm (2012).
11.4 Chemical Synthesis
In 1950 was described by Karrer and Eugster (1950), Inhoffen et al. (1950), and
Milas et al. (1950), the chemical synthesis of pigments, starting with the synthesis of
β-carotene. The scientific achievements of these three groups were the basis for the
industrial production procedures. In 1954, Hoffmann-La Roche began commercial
production of β-carotene. The method based on the Grignard reaction, which follows
the synthesis principle C19 + C2 + C19, it presented a yield of 60%. In 1960, the
BASF developed a higher yield method (85%) based on Wittig reaction (C20 + C20).
The disadvantage of the Wittig reaction-based process is the undesirable formation of
triphenylphosphine oxide, which needs of recycling due to its low biodegradability
(Ribeiro et al. 2011).
Today, the two largest industrial producers are DSM and BASF, which produce the
β-apo-8’-carotenal, β-carotene, canthaxanthin, astaxanthin, lutein, lycopene, zeaxanthin, and citranaxanthin pigments. Although chemical synthesis is a consolidated
market, it became less desirable, given the awareness of the benefits associated
with natural dyes. In this context, several companies are concentrated on developing methods for producing pigments from photoautotrophic cultures (Cardoso
et al. 2017).