Biology Reference
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human nutrition, while supplementing others (Fabregas and Herrero,
1990). These phytoplankton, therefore, constitute the initial component of
the food web, providing food for various oceanic creatures, which include
shellfi sh species, consisting of crayfi sh, shellfi sh, crab, shrimp and lobster,
mollusks including bivalves such as mussel, oyster, and scallop, univalve
creatures such as abalone, snail and conch, and the cephalopods, squid,
cuttlefi sh and octopus. The high protein contents of many microalgae,
which range from 39-54% of dry matter, make them useful as single cell
protein. Besides, they also contain up to 29% carbohydrates and 18%
lipids and are also rich in many minerals including calcium, sodium,
magnesium, zinc, iron, manganese, copper and nickel. They also contain
saturated, mono- and poly-unsaturated fatty acids (Madigan and
Martinko, 2005). Some of the important microalgae, which have been
well studied in this respect, include species of Chlorella , Spirulina and
Dunaliella (Prabhudas et al., 2009; Adams, 1997). Chlorella is a genus of
single-celled green algae, belonging to the phylum, having a spherical
shape of about 2 to 10 ┬Ám dia. The alga contains the green photosynthetic
pigments chlorophyll-a and chlorophyll-b in its chloroplasts. It multiplies
rapidly through photosynthesis, requiring only CO 2 , water, sunlight and
minerals for growth. Chlorella could serve as a potential source of food
because of its high contents of proteins and other essential nutrients.
Spirulina are unicellular, photosynthetic blue green algae (cyanobacteria).
They have no cellulose in its cell walls, which are composed of soft muco-
polysaccharides. The algae are microscopic in nature and occur naturally
in warm, alkaline, salty, brackish lakes. Its color is derived from the
green pigment of chlorophyll, and from the blue color of a protein called
phycocyanin. The common Spirulina , which are used as human and animal
food supplements are the species, S. maxima and S. platensis . Regular
consumption of Spirulina may lower cholesterol, serum lipids, and low-
density lipoprotein. Spirulina reduce the severity of strokes and improves
recovery of movement after a stroke; reverses age-related and learning;
and prevents and treats hay fever (Prabhudas et al., 2009; Sen and Sarkar,
2004). Regular intake of Spirulina was also shown to potentially limit brain
damage from strokes and other neurological disorders (Wang et al., 2005a).
The genus Dunaliella includes halo-tolerant, unicellular, motile green algae
with exceptional morphological and physiological properties belonging
to the family Chlorophyceae. It grows in high (1.5 M) salt concentration
(Adams, 1997).
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