Page 291 - Algae Anatomy, Biochemistry, and Biotechnology

274 Algae: Anatomy, Biochemistry, and Biotechnology

then dried, either by spreading and air-drying or by using rotary dryers, and exported to the U.S. and
Denmark for processing.
Carrageenan production (valued at U.S. $240 million annually) was originally dependent on
wild macroalgae, especially Chondrus crispus (Irish moss), a small macroalgae growing in cold
waters, with a limited resource base in France, Ireland, Portugal, Spain, and the east coast provinces
of Canada. As the carrageenan industry expanded, the demand for raw material began to strain the
supply from natural resources. However, since the early 1970s the industry has expanded rapidly
following the availability of other carrageenan-containing macroalgae that have been successfully
cultivated in warmwater countries with low labor costs. Today, most raw material comes from two
species originally cultivated in the Philippines, Kappaphycus alvarezii and Eucheuma denticula-
tum, but which are now also cultivated in other warm-water countries such as Indonesia and the
United Republic of Tanzania. Limited quantities of wild Chondrus are still used; attempts to culti-
vate Chondrus in tanks have been successful biologically, but it has proved uneconomic as a raw
material for carrageenan. Wild species of Gigartina and Iridaea from Chile are also being harvested
and efforts are being made to find cultivation methods for these.
Table 7.6 summarizes commercially exploited algae and the corresponding extract.

ANIMAL FEED
Microalgae are utilized in aquaculture as live feeds for all growth stages of bivalve molluscs (e.g.,
oysters, scallops, clams, and mussels), for the larval/early juvenile stages of abalone, crustaceans,

TABLE 7.6
Summary of Commercially Exploited Algae and the Corresponding
Extracts
Scientific Name Class Extracts

Gracilaria chilensis Floridophyceae Agar
Ahnfeltia plicata Floridophyceae Agar/Carrageenan
Gelidium lingulatum Floridophyceae Agar
Pterocladia spp. Floridophyceae Agar
Hypnea spp. Floridophyceae Agar
Chondrus crispus Floridophyceae Carrageenan
Gigartina skottsbergii Floridophyceae Carrageenan
Gigartina canaliculata Floridophyceae Carrageenan
Mazzaella laminaroides Floridophyceae Carrageenan
Sarcothalia crispata Floridophyceae Carrageenan
Kappaphycus alvarezii Floridophyceae Carrageenan
Eucheuma denticulatum Floridophyceae Carrageenan
Iridaea spp. Floridophyceae Carrageenan
Laminaria hyperborea Phaeophyceae Alginate
Laminaria digitata Phaeophyceae Alginate
Laminaria japonica Phaeophyceae Alginate
Laminaria saccarina Phaeophyceae Alginate
Macrocystis pyrifera Phaeophyceae Alginate
Ascophyllum nodosum Phaeophyceae Alginate
Durvillea potatorum Phaeophyceae Alginate
Ecklonia spp. Phaeophyceae Alginate
Lessonia nigrescens Phaeophyceae Alginate
Lessonia trabiculata Phaeophyceae Alginate