14 The Bioeconomy of Production of Microalgal Pigments
339
are the major microalgal phycobiliproteins (Sekar and Chandramohan 2008). The
optical absorbance of allophycocyanin is 650–655 nm, phycocyanin is 615–640 nm,
phycoerythrin is 565 ~ 575 nm and phycoerythrocyanin is 577 nm. Thus, phycobiliproteins absorb light in the visible spectrum and acts as accessory light collecting
pigments during photosynthesis (Batista et al. 2006). Phycobiliproteins are made of
α and β polypeptides, having a molecular weight of 15 kDa and 22 kDa, respectively,
that associates non-covalently to form heterodimers (Glazer 1994).
Two polypeptide chains with methionine was present in c-phycocyanin protein
that is isolated from Oscillatoria agardhii microalgae (Peters et al. 1992). These two
polypeptide chains are linked by disulphide bonds and each chain contains a single
chromophore group. The composition of amino acids and N-terminal sequences of
both polypeptides are also found to be similar. In complete phycobilisome, Allophycocyanin is present in the core of phycobiliproteins that are joined to the disc-shaped
hexameric phycocyanins to the proximal side and distal side phycoerythrins present
in the core. The prosthetic groups in covalent arrangement with phycobilins led to
exclusive phycobiliprotein colors (Sekar and Chandramohan 2008). About 10–15%
of total phycobiliprotein consists of uncolored or linker polypeptides which are not
only the structural components that stabilizes PBS, but also helps in the efficient
energy flow to the reaction center of photosynthesis.
Most abundant phycobiliproteins produced by red algae Porphyridium are phycoerythrins, while cyanobacteria Arthrospira Spirulina have phycocyanins as the major
pigment (Glazer 1994; Bermejo Roman et al. 2002). The core pigment in Nostoc
strains is C-phycoerythrin and it makes 10% of the microalgal dry weight. A strain
of Ananbena having 8.3% dry weight of phycoerythrin was isolated from coastal
lagoons of Spain (Rodriguez et al. 1991). Heterocyst containing strains of cyanobacteria were found to be high producers of phycobiliproteins among 41 cyanobacterial species, including unicellular, colonial, filamentous (heterocystous and nonheterocystous) and heterotrichous strains (Kaushik 2000). Phycoerythrin and phycocyanin also have a direct effect on total phycobiliprotein production. Analysis of
20 Tolypothrix strains of their phycobilin content revealed significant differences at
both inter- and intraspecies level (Prasanna et al. 2003).
Various potential algal species for phycobiliprotein production are screened and it
was found that Spirulina fusiformis produced 6 to 46% of c-phycocyanin and about
26% in Spirulina platensis (Zhu et al. 2007; Madhyastha et al. 2006). Moreover, the
high heterotrophic cell density, continuous and fed batch unicellular red algae culture
of Galdieria sulphuraria also produced large quantities of phycocyanin (Graverholt
and Eriksen 2007). For extraction of phycobiliproteins, cell disruption methods such
as osmotic shock, enzyme treatment, or high-pressure homogenization is used. The
crude extract is then directly used for purification of pigments. Moreover, a combination of methods is also used depending on the desired purity and source organism. The
purified pigment is dried by lyophilization to prevent its denaturation. Recently, highpressure homogenization is utilized for extraction of phycocyanin from S. platensis
(Seo et al. 2013). Likewise, chromatography coupled with expanded bed adsorption
339
are the major microalgal phycobiliproteins (Sekar and Chandramohan 2008). The
optical absorbance of allophycocyanin is 650–655 nm, phycocyanin is 615–640 nm,
phycoerythrin is 565 ~ 575 nm and phycoerythrocyanin is 577 nm. Thus, phycobiliproteins absorb light in the visible spectrum and acts as accessory light collecting
pigments during photosynthesis (Batista et al. 2006). Phycobiliproteins are made of
α and β polypeptides, having a molecular weight of 15 kDa and 22 kDa, respectively,
that associates non-covalently to form heterodimers (Glazer 1994).
Two polypeptide chains with methionine was present in c-phycocyanin protein
that is isolated from Oscillatoria agardhii microalgae (Peters et al. 1992). These two
polypeptide chains are linked by disulphide bonds and each chain contains a single
chromophore group. The composition of amino acids and N-terminal sequences of
both polypeptides are also found to be similar. In complete phycobilisome, Allophycocyanin is present in the core of phycobiliproteins that are joined to the disc-shaped
hexameric phycocyanins to the proximal side and distal side phycoerythrins present
in the core. The prosthetic groups in covalent arrangement with phycobilins led to
exclusive phycobiliprotein colors (Sekar and Chandramohan 2008). About 10–15%
of total phycobiliprotein consists of uncolored or linker polypeptides which are not
only the structural components that stabilizes PBS, but also helps in the efficient
energy flow to the reaction center of photosynthesis.
Most abundant phycobiliproteins produced by red algae Porphyridium are phycoerythrins, while cyanobacteria Arthrospira Spirulina have phycocyanins as the major
pigment (Glazer 1994; Bermejo Roman et al. 2002). The core pigment in Nostoc
strains is C-phycoerythrin and it makes 10% of the microalgal dry weight. A strain
of Ananbena having 8.3% dry weight of phycoerythrin was isolated from coastal
lagoons of Spain (Rodriguez et al. 1991). Heterocyst containing strains of cyanobacteria were found to be high producers of phycobiliproteins among 41 cyanobacterial species, including unicellular, colonial, filamentous (heterocystous and nonheterocystous) and heterotrichous strains (Kaushik 2000). Phycoerythrin and phycocyanin also have a direct effect on total phycobiliprotein production. Analysis of
20 Tolypothrix strains of their phycobilin content revealed significant differences at
both inter- and intraspecies level (Prasanna et al. 2003).
Various potential algal species for phycobiliprotein production are screened and it
was found that Spirulina fusiformis produced 6 to 46% of c-phycocyanin and about
26% in Spirulina platensis (Zhu et al. 2007; Madhyastha et al. 2006). Moreover, the
high heterotrophic cell density, continuous and fed batch unicellular red algae culture
of Galdieria sulphuraria also produced large quantities of phycocyanin (Graverholt
and Eriksen 2007). For extraction of phycobiliproteins, cell disruption methods such
as osmotic shock, enzyme treatment, or high-pressure homogenization is used. The
crude extract is then directly used for purification of pigments. Moreover, a combination of methods is also used depending on the desired purity and source organism. The
purified pigment is dried by lyophilization to prevent its denaturation. Recently, highpressure homogenization is utilized for extraction of phycocyanin from S. platensis
(Seo et al. 2013). Likewise, chromatography coupled with expanded bed adsorption