25 Cosmetics and Cosmeceutical Applications of Microalgae Pigments
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dry weight for 1 L culture (Borowitzka 1999). In closed system, usually known as
photobioreactor, microalgae cells are well mixed with nutrients and CO 2 , in closed
vessel with controlled intensity of light. This system is highly sterile, with controlled
parameter conditions, which allowed this system to culture various species of algae
without worries about contamination. The productivity of this system is relatively
higher than open air system, but it consumes huge amount of energy to operating
this system, and of course spend more cost (Hosikian et al. 2010).
In a batch culture, microalgae growth shows a typical growth curve, which is
divided into four phases in order to their cell number: lag phases where the growth
is still low due to adaptation process, followed by logarithmic phase which means
the cell growth is exponential. At this phase, growth rate is relatively high until
some parameters become limited, for example, nutrient depletion, or accumulation
of metabolic waste. Reaching this condition, growth rate decline leads to stationary
phase, followed by death phase when environmental conditions do not meet the
growth requirements. Recirculating water culture system can prolong the culture
condition, where the metabolic waste can be minimized by treatment and nutrients
can be added several times. But most of microalgae culture are intend to harvest
at one time, so batch culture is preferable to use than recirculating water system.
There are various techniques to perform batch culture, raceway ponds are the most
popular and are the preferred production system for the large scale among them,
some biggest microalgae companies use this system such as Hawaiian microalgae
company, Cyanotech Corporation, Seambiotic in Israel, and Earthrise in California,
in which their main business is spirulina in massive raceway ponds (Hosikian et al.
2010).
25.2 Pigments in Microalgae
Microalgae are excellent sources of natural pigments with chlorophylls, carotenoids
(carotenes and xanthophylls), and phycobilins as the main types. Chlorophylls and
carotenoids are generally fat soluble whereas, phycobilins are water soluble (Pangestuti and Kim 2011). Chlorophylls are greenish natural pigments which contain a
porphyrin ring and found in all algae, higher plants, and cyanobacteria. Structurally,
chlorophylls are substituted tetrapyrrole with a centrally bound magnesium atom;
the porphyrin tetrapyrrole is further esterified to a diterpene alcohol, phytol, to form
chlorophyll. There are several types of chlorophylls with differences in some macrocycle peripheral groups, which affect their absorption spectra. Differing with other
types of chlorophylls, Chl c lacks the hydrocarbon tail which leads to differences in
the absorption spectrum and therefore tonality, as Chl a appears blue green, Chl b
brilliant green, Chl c yellow green, Chl d brilliant/forest green, and Chl f emerald
green (Mulders et al. 2014). Due to the chemical structures, each chlorophyll showed
different stability and Chl a showed better stability than other types of chlorophylls.
Chl a is the most abundant pigment in all microalgae. The European current legislation (Regulation (EC) No 1333/2008 and its amendments) has allowed the use of
615
dry weight for 1 L culture (Borowitzka 1999). In closed system, usually known as
photobioreactor, microalgae cells are well mixed with nutrients and CO 2 , in closed
vessel with controlled intensity of light. This system is highly sterile, with controlled
parameter conditions, which allowed this system to culture various species of algae
without worries about contamination. The productivity of this system is relatively
higher than open air system, but it consumes huge amount of energy to operating
this system, and of course spend more cost (Hosikian et al. 2010).
In a batch culture, microalgae growth shows a typical growth curve, which is
divided into four phases in order to their cell number: lag phases where the growth
is still low due to adaptation process, followed by logarithmic phase which means
the cell growth is exponential. At this phase, growth rate is relatively high until
some parameters become limited, for example, nutrient depletion, or accumulation
of metabolic waste. Reaching this condition, growth rate decline leads to stationary
phase, followed by death phase when environmental conditions do not meet the
growth requirements. Recirculating water culture system can prolong the culture
condition, where the metabolic waste can be minimized by treatment and nutrients
can be added several times. But most of microalgae culture are intend to harvest
at one time, so batch culture is preferable to use than recirculating water system.
There are various techniques to perform batch culture, raceway ponds are the most
popular and are the preferred production system for the large scale among them,
some biggest microalgae companies use this system such as Hawaiian microalgae
company, Cyanotech Corporation, Seambiotic in Israel, and Earthrise in California,
in which their main business is spirulina in massive raceway ponds (Hosikian et al.
2010).
25.2 Pigments in Microalgae
Microalgae are excellent sources of natural pigments with chlorophylls, carotenoids
(carotenes and xanthophylls), and phycobilins as the main types. Chlorophylls and
carotenoids are generally fat soluble whereas, phycobilins are water soluble (Pangestuti and Kim 2011). Chlorophylls are greenish natural pigments which contain a
porphyrin ring and found in all algae, higher plants, and cyanobacteria. Structurally,
chlorophylls are substituted tetrapyrrole with a centrally bound magnesium atom;
the porphyrin tetrapyrrole is further esterified to a diterpene alcohol, phytol, to form
chlorophyll. There are several types of chlorophylls with differences in some macrocycle peripheral groups, which affect their absorption spectra. Differing with other
types of chlorophylls, Chl c lacks the hydrocarbon tail which leads to differences in
the absorption spectrum and therefore tonality, as Chl a appears blue green, Chl b
brilliant green, Chl c yellow green, Chl d brilliant/forest green, and Chl f emerald
green (Mulders et al. 2014). Due to the chemical structures, each chlorophyll showed
different stability and Chl a showed better stability than other types of chlorophylls.
Chl a is the most abundant pigment in all microalgae. The European current legislation (Regulation (EC) No 1333/2008 and its amendments) has allowed the use of