Page 301 - Algae

284 Algae: Anatomy, Biochemistry, and Biotechnology

inside the cell, represent a taxonomic feature. Paramylon consists of b-1,3-glucan, a linear poly-
saccharide found in the cell walls of many bacteria, plants, and yeasts. It belongs to a group of natu-
rally occurring polysaccharides such as lentinan, fungal glucans, sizofiran, and pachyman, which
are considered bioactive compounds. Lentinan and sizofiran are known to inhibit the growth of
various tumors, whereas fungal glucans are used clinically for their stimulatory effect on the
immune system, in particular on the macrophages. The main interest in b-glucans stems from
their ability to act as nonspecific immune system stimulants, by binding to a specific site on mono-
cytes/macrophages and granulocytes. They have been successfully used in aquaculture to
strengthen the nonspecific defence of many important species of fishes and shrimps by injection,
immersion, or in the feed. Sulfated derivatives of Euglena paramylon, in particular, have shown
anti-HIV (human immunodeficiency virus) activity. Moreover, it has been suggested that this poly-
saccharide has a cholesterol-lowering effect when incorporated in the diet of either humans or
animals, and moderates the postprandial blood glucose and insulin response in humans. Since
Euglena gracilis can accumulate large quantities of paramylon when grown in the presence of
an utilizable carbon source, it could represent an alternative source of this compound to Sacchar-
omyces cerevisiae (baker’s yeast), which is currently exploited industrially for its extraction. More-
over, Euglena has been investigated as a potential protein source, and a promising dietary

TABLE 7.7
Summary of Commercially Exploited Algae and the Corresponding
Products or Applications
Scientific Name Class Products/Applications

Lyngbya lagerheimii Cyanophyceae Sulpholipids/spirulan
Nostoc spp. Cyanophyceae Cryptophycin 1
Arthrospira spp. Cyanophyceae Health food
Palmaria mollis Floridophyceae Abalone feed
Phymatolithon calcareum Floridophyceae Fertilizers
Lithothamnion coralloides Floridophyceae Fertilizers
Nannochloropsis spp. Eustigmatophyceae EPA/fish fry feed
Monodus subterraneus Eustigmatophyceae EPA
Skeletonema spp. Bacillariophyceae Fish fry feed
Chaetoceros spp. Bacillariophyceae Fish fry feed
Nitzschia alba Bacillariophyceae EPA
Nitzschia laevis Bacillariophyceae EPA
Petalonia binghamiae Phaeophyceae fucoxanthin
Scytosiphon lomentaria Phaeophyceae fucoxanthin
Ascophyllum nodosum Phaeophyceae Fertilizers
Sargassum spp. Phaeophyceae Fertilizers
Laminaria digitata Phaeophyceae Animal feed
Macrocystis pyrifera Phaeophyceae Abalone feed
Isochrysis spp. Haptophyceae DHA/fish fry feed
Tetraselmis spp. Haptophyceae Fish fry feed
Pavlova spp. Haptophyceae Fish fry feed
Crypthecodinium cohni Dinophyceae DHA
Euglena gracilis Euglenophyceae b-1,3-glucan
Haematococcus pluvialis Chlorophyceae astaxanthin
Dunaliella salina Chlorophyceae b-carotene
Chlorella spp. Chlorophyceae Health food/fish fry feed