Biomedical Engineering Reference
In-Depth Information
eyeliner and lipstick (Spoalore et al., 2006; Milledge, 2011). Although not produced
commercially, the red alga Porphyridium aerugineum was used to produce a blue
color that is added to Pepsi ® and Bacardi Breezer ® (Dufossé et  al., 2005). It is no
surprise that the global market for phycobiliprotein colorants alone was estimated at
US$50 million by 2010 (Del Campo et al., 2007), with prices varying from US$3 to
US$25 mg −1 (Spolaore et al., 2006; Milledge, 2011).
10.2.2.2 Production Process
Phycocyanin is employed as a colorant to a greater degree compared to phycoer-
ythrin, which is incorporated more frequently in fluorescent applications. This is
evident in their production yields (Table  10.4), where C-phycocyanin yields are
reported to be as high as 46%, which is consistent with its broad application profile.
C-phycocyanin (PC) is the source of blue coloring and is commercially produced
from Spirulina, Porphyridium, and Rhodella (Milledge, 2011).
The majority of the commercial production of PC occurs in outdoor, photo-
autotrophic open raceway ponds predominantly in subtropical locations around
the  Pacific  Ocean, specifically with Spirulina platensis (Spolaore et  al., 2006;
Eriksen, 2008). The range of commercial applications drives the production of
high-purity phycobiliproteins—through extraction from the phycobilisomes fol-
lowed by purification. The extraction process is particularly difficult because of the
rigid cellular wall and the small size of the cell. Therefore, physical or chemical cell
disruption is necessary to increase the bioavailability and assimilation of phyco-
biliproteins from the cells (Molina-Grima, 2003; Sekar and Chandramohan, 2008).
There are a number of extraction methods available to aid in the cell disruption
process, of which include sonication with sand (mainly small-particle silica), French
press, tissue grinding (with or without liquid nitrogen), homogenization, and causing
osmotic shock with use of dilute phosphate buffer. Upon comparing all the extrac-
tion methods tested, freezing and thawing of cells with liquid nitrogen, followed by
grinding with a mortar and pestle (with an abrasive material) and homogenization
at 10,000 rpm yielded almost 20% phycocyanin from Spirulina dry biomass (Sekar
and Chandramohan, 2008).
There exists a range of patents detailing various cultivation and harvesting
systems, extraction methods, and purification and production processes for phyco-
biliproteins. Purification of phycoerythrin includes distilled water leaching, staged
precipitation with ammonium sulfate, and ion-exchange chromatography (Sekar and
Chandramohan, 2008). Good-quality algal pigments, specifically with respect to
color tone and thermal stability, were patented for use as colorants in food. Such
pigments were obtained by evaporating an aqueous solution containing trehalose
and algal pigments to dryness (Sekar and Chandramohan, 2008). Consistently and
efficiently cultivating large amounts of algae throughout the year without being
affected by conditions of the culturing site can be challenging. Thus, methods have
been patented to proliferate the growth of algae by irradiating the culture with
monochromatic light at a wavelength of 600 nm. Cultivation of cyanobacteria under
a magnetic field for the production of phycobiliproteins was patented for Spirulina
and Colarina . This involves charging the algae in a test tube, by placing the test tube
between the N- and S-poles of a magnet, such that both poles oppose each other on
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