Environmental Engineering Reference
In-Depth Information
microalgae makes it an attractive platform for
biorefinary concept (Skjanes et al.
2013
).
ʲ-carotenoids has high antioxidant properties and
are used in food industry. ʲ-carotenoids from
Du-
naliella
salina
(Cowan et al.
1995
) and astxan-
thin from
Haematococcus pluvialis
(Guerin et al.
2003
) are the most successful commercial prod-
ucts (Lamers et al.
2012
; Skjanes et al.
2013
).
Astaxanthin has been approved by the US Food
and Drug Administration (US FDA) as a food ad-
ditive for use in the aquaculture as well as for use
as a dietary supplement (Guerin et al.
2003
). The
annual worldwide market for astaxanthin was
estimated at US$ 200 million in 2004, with es-
timations of the global astaxanthin market rising
to US$ 257 million in 2009. Synthetic astaxan-
thin is valued at US$ 2500/kg, while the natural
product is sold for over US$ 7000/kg (Yen et al.
2013
). Phycobillins are another category of algal
pigments which exhibit high fluorescence, and
have wide absorption spectrum. These properties
of phycobillins make them useful in diagnostic
industry (Spolaore et al.
2006
). Spirullina
sp.
produces blue phycobiliproteins (APC) (Sarada
et al.
1999
) and red algae such as
Porphyridium
produces red phycobillins (R-PE) (Munier et al.
2014
). The global phycobillins market was es-
timated to be approximately US$ 50 million in
1997, with prices varying from US$ 3/mg to
US$ 25/mg (Yen et al.
2013
). Green microalgae
produce some other pigments such as,
Scenedes-
mus obliquus
and
Botrycococcus sp.
are the pro-
ducers of lutein,
Dunaliella Salina
and
Chlorella
pyrenoidosa
are the producers of zeaxanthin, and
Chlorella vulgaris
and
Chlorococcum sp.
are the
producers of canaxanthin (Table
8.1
).
a.
Pigments
Colorful appearance of the microalgae is because
of the pigments which capture light and initiate
photosynthesis (Spolaore et al.
2006
). Algae can
be classified on the basis of pigmentation, as
particular class of algae contains specific pig-
ments such as chlorophyll in green algae, phyco-
bilin pigments phycocyanin in blue-green algae,
phycoerthirine in red algae, and fucoxanthin in
brown algae (Borowitzka
2013
). Chlorophyll a is
the most abundant pigment in all photosynthetic
organisms, and it absorbs energy from the light,
and then serves as a primary electron donor in the
electron transport chain (Spolaore et al.
2006
).
Chlorophyll can be used as an anti-inflammatory
and wound healing additive to pharmaceuticals
(Yen et al.
2013
). Pheophorbide a is a chlorophyll
derivative compound which is used in photody-
namic therapy (PDT) used for the treatment of
cancer (Yen et al.
2013
). Carotenoids are pig-
ments present in all classes of algae and serve
as photoprotectors against the photooxidative
damage resulting from excess energy captured
by light-harvesting antenna (Cardozo et al.
2007
;
Skjanes et al.
2013
). Some of the carotenoids iso-
lated from microalgae like ʲ-carotenoids, astax-
anthin, cantaxanthin, zeaxanthin, and lutein have
commercial importance (Skjanes et al.
2013
).
These pigments found their application in food,
pharma, and cosmetic industry and attract high
cost in commercial market (Lamers et al.
2012
;
Vanthoor-Koopmans et al.
2013
). In the biofuel
production process, coproduction of these high
value pigments greatly improves the econom-
ics (Draaisma et al.
2013
). Astaxanthin is an
oxidized from of carotenoid with high oxidation
capacity. Astaxanthin has many applications in
healthcare industry as it can be used for preven-
tion and treatment of various conditions, such as
chronic inflammatory diseases, eye diseases, skin
diseases, cardiovascular diseases, cancers, neuro-
degenerative diseases, liver diseases, metabolic
syndrome, diabetes, diabetic nephropathy, and
gastrointestinal diseases (Wayama et al.
2013
).
b.
Nutraceuticals
Nutraceuticals are the group of compounds
which can be used for consumption as food with
medicinal benefits. Humans and animals are de-
pendent on plants for many nutrient supplements
as they cannot be synthesized in their body. Mi-
croalgae can synthesize numerous compounds
that have nutraceutical values. Microalgae have
become a ubiquitous source of nutraceuticals
due to the capability of producing necessary vi-
tamins including A (Retinol), B1 (Thiamine), B2
(Riboflavin), B3 (Niacin), B6 (Pyridoxine), B9
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