Algae is an informal term for a large and diverse group of photosynthetic, eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular microalgae, such as Chlorella, Prototheca and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to 50 metres (160 ft) in length. Most are aquatic and lack many of the distinct cell and tissue types, such as stomata, xylem and phloem that are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the Charophyta, a division of green algae which includes, for example, Spirogyra and stoneworts. Algae that are carried by water are plankton, specifically phytoplankton.
Agar, or agar-agar, is a jelly-like substance consisting of polysaccharides obtained from the cell walls of some species of red algae, primarily from "ogonori" (Gracilaria) and "tengusa" (Gelidiaceae). As found in nature, agar is a mixture of two components, the linear polysaccharide agarose and a heterogeneous mixture of smaller molecules called agaropectin. It forms the supporting structure in the cell walls of certain species of algae and is released on boiling. These algae are known as agarophytes, belonging to the Rhodophyta phylum. The processing of food-grade agar removes the agaropectin, and the commercial product is essentially pure agarose.
Chondrus crispus—commonly called Irish moss or carrageen moss —is a species of red algae which grows abundantly along the rocky parts of the Atlantic coasts of Europe and North America. In its fresh condition this protist is soft and cartilaginous, varying in color from a greenish-yellow, through red, to a dark purple or purplish-brown. The principal constituent is a mucilaginous body, made of the polysaccharide carrageenan, which constitutes 55% of its dry weight. The organism also consists of nearly 10% dry weight protein and about 15% dry weight mineral matter, and is rich in iodine and sulfur. When softened in water it has a sea-like odour. Because of the abundant cell wall polysaccharides, it will form a jelly when boiled, containing from 20 to 100 times its weight of water.
Carrageenans or carrageenins are a family of natural linear sulfated polysaccharides that are extracted from red edible seaweeds. Carrageenans are widely used in the food industry, for their gelling, thickening, and stabilizing properties. Their main application is in dairy and meat products, due to their strong binding to food proteins. In recent years, carrageenans have emerged as a promising candidate in tissue engineering and regenerative medicine applications as they resemble native glycosaminoglycans (GAGs). They have been mainly used for tissue engineering, wound coverage, and drug delivery.
A thickening agent or thickener is a substance which can increase the viscosity of a liquid without substantially changing its other properties. Edible thickeners are commonly used to thicken sauces, soups, and puddings without altering their taste; thickeners are also used in paints, inks, explosives, and cosmetics.
Galactan (galactosan) is a polysaccharide consisting of polymerized galactose. In general, galactans in natural sources contain a core of galactose units connected by α(1→3) or α(1→6), with structures containing other monosaccharides as side-chains.
Fucoidan is a long chain sulfated polysaccharide found in various species of brown algae. Commercially available fucoidan is commonly extracted from the seaweed species Fucus vesiculosus, Cladosiphon okamuranus, Laminaria japonica and Undaria pinnatifida. Variant forms of fucoidan have also been found in animal species, including the sea cucumber.
Mastocarpus stellatus, commonly known as carrageenan moss or false Irish moss, is a species in the Rhodophyceae division, a red algae seaweed division, and the Phyllophoracea family. M. stellatus is closely related to Irish Moss. It grows in the intertidal zone. It is most collected in North Atlantic regions such as Ireland and Scotland, together with Irish moss, dried, and sold for cooking and as the basis for a drink reputed to ward off colds and flu. Marine biologists have completed studies on the medicinal reputation of M. stellatus to discover the full potential of its pharmaceutical benefits. Additionally, marine biologists have conducted research on its potential to serve as an alternative to plastic. The application of M. stellatus in these different industries is correlated with the seaweed's adaptations which developed in response to the environmental stressors present around its location on the rocky intertidal.
Monostroma is a genus of marine green algae (seaweed) in the family Monostromataceae. As the name suggests, algae of this genus are monostromatic. Monostroma kuroshiense, an algae of this genus, is commercially cultivated in East Asia and South America for the edible product "hitoegusa-nori" or "hirohano-hitoegusa nori", popular sushi wraps. Monostroma oligosaccharides with degree of polymerization 6 prepared by agarase digestion from Monostroma nitidum polysaccharides have been shown to be an effective prophylactic agent during in vitro and in vivo tests against Japanese encephalitis viral infection. The sulfated oligosaccharides from Monostroma seem to be promising candidates for further development as antiviral agents. The genus Monostroma is the most widely cultivated genus among green seaweeds.
Kappaphycus alvarezii, the elkhorn sea moss, is a species of red algae. The elkhorn sea moss varies in size, weight, and age. It is a dark greenish-brown hue and can sometimes be deep purple. The moss is cylindrical in shape throughout the seaweed. Its diameter averages 1.526 mm when dried. Near the base of the seaweed, its average length is from 1 mm to 17 mm and 1 mm to 2 mm in diameter. Firm algae are around 2 m tall, with axes and branches around 1–2 cm in diameter. It used to be believed they reproduced through vegetative fermentation, but recent studies show that they reproduce sexually. They reproduce through vegetative propagation and reproduce sexually. Cross sections of the Elkhorn sea moss have a medulla composed of small thick-walled cells interspaced among large parenchyma cells. This moss is used for various types of foods that humans consume and can also be used to make a jelly-like dessert. This moss is a very good source of minerals and of high commercial interest. It is one of the most important commercial sources of carrageenans, a family of gel-forming, viscosifying polysaccharides. Farming methods affect the character of the carrageenan that can be extracted from the seaweed. It is very fast-growing, known to double its biomass in 15 days.
Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of Rhodophyta (red), Phaeophyta (brown) and Chlorophyta (green) macroalgae. Seaweed species such as kelps provide essential nursery habitat for fisheries and other marine species and thus protect food sources; other species, such as planktonic algae, play a vital role in capturing carbon, producing at least 50% of Earth's oxygen.
Red algae, or Rhodophyta, are one of the oldest groups of eukaryotic algae. The Rhodophyta comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority of species (6,793) are found in the Florideophyceae (class), and mostly consist of multicellular, marine algae, including many notable seaweeds. Red algae are abundant in marine habitats but relatively rare in freshwaters. Approximately 5% of red algae species occur in freshwater environments, with greater concentrations found in warmer areas. Except for two coastal cave dwelling species in the asexual class Cyanidiophyceae, there are no terrestrial species, which may be due to an evolutionary bottleneck in which the last common ancestor lost about 25% of its core genes and much of its evolutionary plasticity.
Edible seaweed, or sea vegetables, are seaweeds that can be eaten and used for culinary purposes. They typically contain high amounts of fiber. They may belong to one of several groups of multicellular algae: the red algae, green algae, and brown algae. Seaweeds are also harvested or cultivated for the extraction of polysaccharides such as alginate, agar and carrageenan, gelatinous substances collectively known as hydrocolloids or phycocolloids. Hydrocolloids have attained commercial significance, especially in food production as food additives. The food industry exploits the gelling, water-retention, emulsifying and other physical properties of these hydrocolloids.
Seaweed farming or kelp farming is the practice of cultivating and harvesting seaweed. In its simplest form farmers gather from natural beds, while at the other extreme farmers fully control the crop's life cycle.
Microalgae or microscopic algae grow in either marine or freshwater systems. They are primary producers in the oceans that convert water and carbon dioxide to biomass and oxygen in the presence of sunlight.
Eucheuma denticulatum is a species of red algae and one of the primary sources of iota carrageenan. It exists naturally in the Philippines, tropical Asia, and the western Pacific, but for the commercial extraction of carrageenan it is usually cultivated. The species is commonly known as E. spinosum when cultivated and can be found in different colours: brown, green and red.
Porphyridium cruentum is a species of red algae in the family Porphyridiophyceae.
Hypnea is a genus of red algae, and a well known carrageenophyte.
Andres Kollist is an Estonian chemist, librarian, politician and activist.
Halymeniales is an order of red algae belonging to the class Florideophyceae and the subclass Rhodymeniophycidae.
