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Encyclopedia > Alga
A seaweed (Laurencia) up close: the "branches" are multicellular and only about 1 mm thick. Much smaller algae are seen growing attached to the structure extending upwards in the lower right quarter
A seaweed (Laurencia) up close: the "branches" are multicellular and only about 1 mm thick. Much smaller algae are seen growing attached to the structure extending upwards in the lower right quarter

Algae (singular alga) encompass several different groups of living organisms that capture light energy through photosynthesis, converting inorganic substances into simple sugars using the captured energy. Algae have been traditionally regarded as simple plants, and some are closely related to the higher plants. Others appear to represent different protist groups, alongside other organisms that are traditionally considered more animal-like (that is, protozoa). Thus algae do not represent a single evolutionary direction or line, but a level of organization that may have developed several times in the early history of life on earth. ImageMetadata File history File links Download high resolution version (900x722, 561 KB) Close-up of a red alga (Laurencia), a marine seaweed from Hawaii. ... ImageMetadata File history File links Download high resolution version (900x722, 561 KB) Close-up of a red alga (Laurencia), a marine seaweed from Hawaii. ... Leaf. ... Divisions Land plants (embryophytes) Non-vascular plants (bryophytes) Marchantiophyta - liverworts Anthocerotophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants Adiantum pedatum (a fern... Divisions Non-vascular plants (bryophytes) Hepaticophyta - liverworts Anthocerotophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants The embryophytes are the most familiar group... Typical phyla Rhodophyta (red algae) Chromista Heterokontophyta (heterokonts) Haptophyta Cryptophyta (cryptomonads) Alveolates Dinoflagellata Apicomplexa Ciliophora (ciliates) Excavates Euglenozoa Percolozoa Metamonada Rhizaria Radiolaria Foraminifera Cercozoa Amoebozoa Choanozoa Many others; classification varies Protists are a heterogeneous group of living things, comprising those eukaryotes that are neither animals, plants, nor fungi. ... Protozoa (in Greek protos = first and zoon = animal) are single-celled eukaryotes (organisms with nuclei) that show some characteristics usually associated with animals, most notably mobility and heterotrophy. ...


Algae range from single-celled organisms to multi-cellular organisms, some with fairly complex differentiated form and (if marine) called seaweeds. All lack leaves, roots, flowers, and other organ structures that characterize higher plants. They are distinguished from other protozoa in that they are photoautotrophic, although this is not a hard and fast distinction as some groups contain members that are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some unicellular species rely entirely on external energy sources and have reduced or lost their photosynthetic apparatus. Seaweed covered rocks in the UK Phycologists consider seaweed to refer any of a large number of marine benthic algae that are multicellular, macrothallic (large-bodied), and thus differentiated from most algae that tend to be microscopic in size (Smith, 1944). ... In botany, a leaf is an above-ground plant organ specialized for photosynthesis. ... Primary and secondary roots in a cotton plant In vascular plants, the root is that organ of a plant body that typically lies below the surface of the soil (compare with stem). ... Clivia miniata bears bright orange flowers. ... Protozoa (in Greek protos = first and zoon = animal) are single-celled eukaryotes (organisms with nuclei) that show some characteristics usually associated with animals, most notably mobility and heterotrophy. ... An autotroph (in Greek eauton = self and trophe = nutrition) is an organism that produces its own cell mass and organic compounds from carbon dioxide as sole carbon source, using either light or chemical compounds as a source of energy. ... The term mixotrophic can describe organisms (usually algae or bacteria) capable of deriving metabolic energy both from photosynthesis and from external energy sources. ... Osmotrophy is the study of osmology, popularly referred to as ubeterology, and it focuses on the interaction between osmots and trophots. ... Myzocytosis is a method of feeding found in some heterotrophic organisms. ... Phagocytosis (literally, cell eating) is a form of endocytosis where large particles are enveloped by the cell membrane of a (usually larger) cell and internalized to form a phagosome, or food vacuole. ...


All algae have photosynthetic machinery ultimately derived from the cyanobacteria, and so produce oxygen as a by-product of photosynthesis, unlike non-cyanobacterial photosynthetic bacteria. Orders The taxonomy of the Cyanobacteria is currently under revision. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ...


Algae are usually found in damp places or bodies of water and thus are common in terrestrial as well as aquatic environments. However, terrestrial algae are usually rather inconspicuous and far more common in moist, tropical regions than dry ones, because algae lack vascular tissues and other adaptions to live on land. Algae can endure dryness and other conditions in symbiosis with a fungus as lichen. Crustose and foliose lichens on a wall A foliose lichen on basalt. ...


The various sorts of algae play significant roles in aquatic ecology. Microscopic forms that live suspended in the water column—called phytoplankton—provide the food base for most marine food chains. In very high densities (so-called algal blooms) these algae may discolor the water and outcompete or poison other life forms. Seaweeds grow mostly in shallow marine waters. Some are used as human food or harvested for useful substances such as agar or fertilizer. The study of algae is called phycology or algology. Diagrams of some typical phytoplankton Phytoplankton refers to the autotrophic component of the plankton that drifts in the water column. ... Food chains and food webs or food networks describe the feeding relationships between species in a biotic community. ... A red tide resulting from a dinoflagellate bloom discoloring the water on the right An algal bloom is a relatively rapid increase in the population of (usually) phytoplankton algae in an aquatic system. ... Seaweed covered rocks in the UK Phycologists consider seaweed to refer any of a large number of marine benthic algae that are multicellular, macrothallic (large-bodied), and thus differentiated from most algae that tend to be microscopic in size (Smith, 1944). ... Agar is a galactose polymer (or agarose) obtained from the cell walls of some species of red algae or seaweed (Sphaerococcus euchema) and species of Gelidium, chiefly from eastern Asia and California. ... Phycology (or algology) is the scientific study of algae. ...

Contents


Relationships among algal groups

Prokaryotic algae

Traditionally the cyanobacteria have been included among the algae, referred to as the cyanophytes or Blue-green Algae, (the term "algae" refers to any aquatic organisms capable of photosynthesis)[1], though some recent treatises on algae specifically exclude them. Cyanobacteria are some of the oldest organisms to appear in the fossil record, dating back about 3.8 billion years (Precambrian). Ancient cyanobacteria likely produced much of the oxygen in the Earth's atmosphere. Orders The taxonomy of the Cyanobacteria is currently under revision. ... Orders The taxonomy of the Cyanobacteria is currently under revision. ... Ever since recorded history began, and probably before, people have found pieces of rock and other hard material with indentations from the remains of dead organisms. ... The Precambrian is an informal name for the eons of the geologic timescale that came before the current Phanerozoic eon. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ...


Cyanobacteria can be unicellular, colonial, or filamentous. They have a prokaryotic cell structure typical of bacteria and conduct photosynthesis directly within the cytoplasm, rather than in specialized organelles. Some filamentous blue-green algae have specialized cells, termed heterocysts, in which nitrogen fixation occurs. [2] Orders The taxonomy of the Cyanobacteria is currently under revision. ... Prokaryotes (from Old Greek pro- before + karyon nut, referring to the cell nucleus, + suffix -otos, pl. ... Cytoplasm is a homogeneous, generally clear jelly-like material that fills cells. ... Cyanobacteria (Greek: cyanos = blue) are a phylum of aquatic bacteria that obtain their energy through photosynthesis. ... Nitrogen fixation is the process by which nitrogen is taken from its relatively inert molecular form (N2) in the atmosphere and converted into nitrogen compounds useful for other chemical processes (such as, notably, ammonia, nitrate and nitrogen dioxide). ...


Eukaryotic algae

All other algae are eukaryotes and conduct photosynthesis within membrane-bound structures (organelles) called chloroplasts. Chloroplasts contain DNA and are similar in structure to cyanobacteria, presumably representing reduced cyanobacterial endosymbionts. The exact nature of the chloroplasts is different among the different lines of algae, possibly reflecting different endosymbiotic events. There are three groups that have primary chloroplasts: Kingdoms Animalia - Animals Fungi Plantae - Plants Protista A eukaryote (also spelled eucaryote) is an organism with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... The inside of a chloroplast Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. ... The endosymbiotic theory concerns the origins of mitochondria and plastids (plastids with chlorophyll a and b are called chloroplasts, some other plastids are called cyanelles and rhodoplasts),which are organelles of eukaryotic cells. ...

In these groups the chloroplast is surrounded by two membranes, both now thought to come from the chloroplast. The chloroplasts of red algae have a more or less typical cyanobacterial pigmentation, while the green algae and higher plants have chloroplasts with chlorophyll a and b, the latter found in some cyanobacteria but not most. There is reasonably solid evidence that these three groups originated from a common pigmented ancestor; i.e., chloroplasts developed in a single endosymbiotic event. Red and green algae have an alternation of generations life cycle. This is the same life cycle as the mosses, suggesting that the mosses evolved from the green algae. Divisions Chlorophyta Charophyta Streptophytina (Subdivision) The green algae are the large group of algae from which the embryophytes (higher plants) emerged. ... Divisions Non-vascular plants (bryophytes) Hepaticophyta - liverworts Anthocerotophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants The embryophytes are the most familiar group... Classes Florideophyceae Bangiophyceae Cyanidiophyceae The red algae (Rhodophyta, pronounced /ˈrəʊdə(ʊ)ˌfʌɪtə/) are a large group of mostly multicellular, marine algae, including many notable seaweeds. ... The glaucophytes, also referred to as glaucocystophytes or glaucocystids, are a tiny group of freshwater algae. ... Sporic or diplohaplontic life cycle. ...


Two other groups have green chloroplasts containing chlorophyll b:

These are surrounded by three and four membranes, respectively, and were probably retained from an ingested green alga. Those of the chlorarchniophytes contain a small nucleomorph, which is the remnant of the alga's nucleus. It has been suggested that the euglenid chloroplasts only have three membranes because they were acquired through myzocytosis rather than phagocytosis. The euglenids are one of the best-known groups of flagellates, commonly found in freshwater especially when rich in organic materials, with a few marine and endosymbiotic members. ... Genera Chlorarachnion Gymnochlora Lotharella Cryptochlora Chlorarachniophytes are a small group of algae occasionally found in tropical oceans. ... In cell biology, the nucleus (from Latin nucleus or nuculeus, kernel) is found in all eukaryotic cells and contains most of the cells genetic material. ... Myzocytosis is a method of feeding found in some heterotrophic organisms. ... Phagocytosis (literally, cell eating) is a form of endocytosis where large particles are enveloped by the cell membrane of a (usually larger) cell and internalized to form a phagosome, or food vacuole. ...


The remaining algae all have chloroplasts containing chlorophylls a and c. The latter chlorophyll type is not known from any prokaryotes or primary chloroplasts, but genetic similarities with the red algae suggest a relationship there. These groups include:

In the first three of these groups (Chromista), the chloroplast has four membranes, retaining a nucleomorph in cryptomonads, and it now appears that they share a common pigmented ancestor. The typical dinoflagellate chloroplast has three membranes, but there is considerable diversity in chloroplasts among the group, some members presumably having acquired theirs from other sources. The Apicomplexa, a group of closely related parasites, also have plastids though not actual chloroplasts, which appear to have a common origin with those of the dinoflagellates. Typical classes Colored groups Chrysophyceae (golden algae) Synurophyceae Actinochrysophyceae (axodines) Pelagophyceae Phaeothamniophyceae Bacillariophyceae (diatoms) Raphidophyceae Eustigmatophyceae Xanthophyceae (yellow-green algae) Phaeophyceae (brown algae) Colorless groups Oomycetes (water moulds) Hypochytridiomycetes Bicosoecea Labyrinthulomycetes (slime nets) Opalinea Proteromonadea The heterokonts or stramenopiles are a major line of eukaryotes. ... The haptophytes (from the Greek hapsis - touch, reflecting their use of the haptonema), classed either as the Prymnesiophyta or Haptophyta, are a group of algae. ... Typical genera Campylomonas Chilomonas Chroomonas Cryptomonas Falcomonas Geminigera Goniomonas Guillardia Hemiselmis Plagioselmis Proteomonas Storeatula Rhodomonas Teleaulax The cryptomonads are a small group of flagellates, most of which have chloroplasts. ... Classes Dinophyceae Noctiluciphyceae Syndiniophyceae The dinoflagellates are a large group of flagellate protists. ... The Chromista are a eukaryotic supergroup, which may be treated as a separate kingdom or included among the Protista. ... Classes & subclasses Class Conoidasida    Gregarinasina    Coccidiasina Class Aconoidasida    Haemosporasina    Piroplasmasina The Apicomplexa are a large group of protozoa, characterized by the presence of an apical complex at some point in their life-cycle. ... Plastids are major organelles found only in plants and algae. ...


Note many of these groups contain some members that are no longer photosynthetic. Some retain plastids, but not chloroplasts, while others have lost them entirely.


Forms of algae

Most of the simpler algae are unicellular flagellates or amoeboids, but colonial and non-motile forms have developed independently among several of the groups. Some of the more common organizational levels, more than one of which may occur in the life cycle of a species, are: Parasitic excavate (Giardia lamblia) Green algae (Chlamydomonas) Flagellates are cells with one or more whip-like organelles called flagella. ... Amoeba (Chaos diffluens) Foraminiferan shells Heliozoan (Actinophrys sol) Amoeboids are cells that move or feed by means of temporary projections, called pseudopods (false feet). ... A life cycle includes the major sexual stages of a species, especially in regard to its ploidy. ...

  • Colonial - small, regular groups of motile cells
  • Capsoid - individual non-motile cells embedded in mucilage
  • Coccoid - individual non-motile cells with cell walls
  • Palmelloid - non-motile cells embedded in mucilage
  • Filamentous - a string of non-motile cells connected together, sometimes branching
  • Parenchymatous - cells forming a thallus with partial differentiation of tissues

In three lines even higher levels of organization have been reached, leading to organisms with full tissue differentiation. These are the brown algae—some of which may reach 70 m in length (kelps)—the red algae, and the green algae. The most complex forms are found among the green algae (see Charales), in a lineage that eventually led to the higher land plants. The point where these non-algal plants begin and algae stop is usually taken to be the presence of reproductive organs with protective cell layers, a characteristic not found in the other alga groups. Mucilage is a thick gluey substance, often produced by plants. ... Thallus is an undifferentiated vegetative tissue (without specialization of function) of some non-mobile organisms, which were previously known as the thallophytes. ... Orders Ascoseirales Chordariales Cutleriales Desmarestiales Dictyosiphonales Dictyotales Ectocarpales Fucales Laminariales (kelps) Scytosiphonales Scytothamnales Sphacelariales Sporochnales Syringodermatales Tilopteridales The brown algae or phaeophytes are a large group of multicellular algae, including many notable seaweeds. ... Families Alariaceae Chordaceae Laminariaceae Lessoniaceae Phyllariaceae Pseudochordaceae Kelp are large seaweeds, belonging to the brown algae and classified in the order Laminariales. ... Classes Florideophyceae Bangiophyceae Cyanidiophyceae The red algae (Rhodophyta, pronounced /ˈrəʊdÉ™(ÊŠ)ËŒfʌɪtÉ™/) are a large group of mostly multicellular, marine algae, including many notable seaweeds. ... Divisions Chlorophyta Charophyta Streptophytina (Subdivision) The green algae are the large group of algae from which the embryophytes (higher plants) emerged. ... Genera Chara Lamprothamnium Nitella Tolypella The Charales are an order of green algae, and are believed to be the closest relatives of the embryophyte plants. ...


Algae and symbioses

Some species of algae form symbiotic relationships with other organisms. In these symbioses, the algae supply photosynthates (organic substances) to the host organism providing protection to the algal cells. The host organism derives some or all of its energy requirements from the alga. Examples include: Common Clownfish (Amphiprion ocellaris) in their magnificent sea anemone (Heteractis magnifica) home. ...

  • lichens - a fungus is the host, usually with a green alga or a cyanobacterium as its symbiont. Both fungal and algal species found in lichens are capable of living independently, although habitat requirements may be greatly different from those of the lichen pair.
  • corals - algae known as zooxanthellae are symbionts with corals. Notable amongst these is the dinoflagellate Symbiodinium, found in many hard corals. The loss of Symbiodinium, or other zooxanthellae, from the host is known as coral bleaching.
  • sponges -

Zooxanthellae are golden-brown endosymbionts of various marine animals and protozoa. ... Orders Scleractinia Corals are gastrovascular marine cnidarians (phylum Cnidaria; class Anthozoa) existing as small sea anemone-like polyps, typically forming colonies of many individuals. ... Coral bleaching results when the symbiotic zooxanthellae (single celled algae) are expelled from the host coral organism due to stress. ...

Uses of algae

Algae are used by man in a great many ways. Because many species are aquatic and microscopic, they are cultured in clear tanks or ponds and either harvested or used to treat effluents pumped through.


Energy source

  • Algae can be used to produce biodiesel, and by estimates can produce vastly superior amounts of oil, compared to land-based crops. Because algae grown to produce biodiesel does not need to meet the requirements of a food crop, it is much cheaper to produce. Also it does not need fresh water or fertilizer (both of which are quite expensive).
  • Algae can be grown to produce hydrogen. In 1939 a german researcher named Hans Gaffron, while working at the University of Chicago, observed that the algae he was studying, Chlamydomonas reinhardtii (a green-algae), would sometimes switch from the production of oxygen to the production of hydrogen.[3] Gaffron never discovered the cause for this change and for many years other scientists failed in their attempts at its discovery. In the late 1990's professor Anastasios Melis a researcher at the University of California at Berkeley discovered that if you deprive the algae of sulfur it will switch from the production of oxygen(normal photosynthesis), to the production of hydrogen. He found that the enzyme responsible for this reaction is hydrogenase, but that the hydrogenase will not cause this switch in the pressence of oxygen. Melis found that depleting the amount of sulfur available to the algae interrupted its internal oxygen flow, allowing the hydrogenase an environment in which it can react, causing the algae to produce hydrogen. [4]

pmb.berkeley.edu Biodiesel sample Biodiesel refers to any diesel-equivalent biofuel made from renewable materials such as vegetable oils or animal fats. ... Binomial name Chlamydomonas reinhardtii Chlamydomonas reinhardtii or Green yeast is a single celled green alga about 10 micrometres in diameter which swims with two flagella. ... A hydrogenase is an enzyme that catalyses the reversible oxidation of molecular hydrogen (H2). ...


Pollution control

  • Algae are used in wastewater treatment facilities, reducing the need for more dangerous chemicals.
  • Algae can be used to capture fertilizers in runoff from farms. If this algae is then harvested, it itself can be used as fertilizer.
  • Algae are used by some powerplants to reduce CO2 emissions[5]. The CO2 is pumped into a pond, or some kind of tank, on which the algae feed.

Fertilizers are chemicals given to plants with the intention of promoting growth; they are usually applied either via the soil or by foliar spraying. ... The word emission generally means sending something out. ...

Nutritional value of algae

  • Algae is commercially cultivated as a nutritional supplement. One of the most popular microalgal species is Spirulina (Arthrospira platensis), which is a Cyanobacteria (known as blue-green algae), and has been hailed by some as a superfood. [6]Other algal species cultivated for their nutritional value include; Chlorella (a green algae), and Dunaliella (Dunaliella salina), which is high in beta-carotene and is used in vitamin C supplements.
  • Algae is sometimes also used as a food, as in the Chinese "vegetable" known as fat choy (which is actually a cyanobacterium).

www.spirulinasource.com Species Spirulina corakiana Spirulina crispum Spirulina labyrinthiformis Spirulina laxa Spirulina laxissima Spirulina major Spirulina meneghiniana Spirulina nordstedtii Spirulina princeps Spirulina subsalsa Spirulina subtilissima Spirulina platensis Spirulina tenerrima Spirulina weissii Spirulina is a genus of filamentous cyanobacteria (commonly called blue-green algae), with a coil-like shape. ... Orders The taxonomy of the Cyanobacteria is currently under revision. ... Chlorellae is a collective name for a single celled algae. ... Carotene is a terpene, an orange photosynthetic pigment, important for photosynthesis. ... Fat choy (Nostic flagelliforme), also known as black moss or hair moss, is a cyanobacterium (a type of fresh water algae) that is used as a vegetable in Chinese cuisine. ... Cyanobacteria (Greek: cyanos = blue) are a phylum of aquatic bacteria that obtain their energy through photosynthesis. ...


The natural pigments produced by algae can be used as an alternative to chemical dyes and coloring agents. [7] In biology, pigment is any material resulting in color in plant or animal cells which is the result of selective absorption. ... A dye can generally be described as a coloured substance that has an affinity to the substrate to which it is being applied. ...


Algal cultivation methods

Algae can be grown in raceway-type ponds and lakes [8] Due to the fact that these systems are "open" to the elements, sometimes called "open-pond" systems, they are much more vulnerable to being invaded by other algal species and bacteria. The number of species that have been successfully cultivated for a given purpose,(ie: as a food source, for oil production, or for pigments.), in an outdoor system, are relatively small. In open systems you do not have control over water temperature, and you have little control over lighting conditions. Depending on where you live the growing season is limited to the warmer months. Some of the benefits of this type of system are that it is one of the cheaper ones to produce - at the most basic you only need to dig a trench or pond. It also has one of the largest production capacities compared to other systems, and depending on how large it's made. A variation on the basic "open-pond" system is to close it off, to cover your pond or pool with a greenhouse. While this usually results in a smaller system, (for economic reasons), it does take care of many of the problems associated with an open system. It allows more species to be able to be grown, it allows the species that you are trying to grow to stay dominant, and it extends the growing season, only slightly if unheated, and if heated it can produce year round. In biology, pigment is any material resulting in color in plant or animal cells which is the result of selective absorption. ...


Algae can be grown in a photobioreactor. A photobioreactor is basically a bioreactor which incorporates some type of light source. While almost anything that it would be possible to grow algae in could technically be called a photobioreactor, the term is more commonly used to define a closed system, as opposed to an open tank, or pond. Because these systems are closed, when used to cultivate algae, everything that the algae need to grow,(carbon dioxide, nutrient-rich water and light), all must be introduced into the system. A pond covered with a greenhouse could be considered a photobioreactor. A bioreactor may refer to any device or system that supports a biologically active environment. ...


Different types of photobioreactors include:

  • Tanks provided with a light source.[9]
  • Polyethylene sleeves or bags.
  • Glass or plastic tubes.

- - - - - - - - - - - - - -

  • www.ornl.govOak Ridge National Laboratory, photobioreactor system using glow plates.
  • [10] tubular photobioreactor
  • [11]Greenfuels photobioreactor at M.I.T.
  • www.aquasearch.comMethods of microalgae cultivation, photobioreactor.
  • www.bgu.ac.il Use of polyethylene sleeves for outdoor cultivation, Glass-tube bioreactor.
  • www.fao.org Algal production.
  • www.dabney.com Closed-pond system.
  • home.bt-webworld.com Algal cultivation supplies, tubular photobioreactor.

MIT redirects here. ...

Harvesting algae

Algae can be harvested using microscreens, by centrifugation, or by flocculation. Centrifugation is a process that involves the use of the centrifugal force for the separation of mixtures. ... Flocculation refers to a process where a solute comes out of solution in the form of floc or flakes. The term is also used to refer to the process by which fine particulates are caused to clump together into floc. ...

  • www.pubmedcentral.gov harvesting of algae by froth flotation(pdf)

Extracting oil from algae

When algae is dried it retains its oil content, which then can be "pressed" out with an oil press. Algal oil can be extracted using chemicals. Benzene and Ether have been used, oil can also be separated by Hexane extraction, which is widely used in the food industry and is relatively inexpensive. [12]. Another method is supercritical fluid/CO2 extraction, CO2 is liquefied under pressure and heated to the point that it has the properties of both a liquid and a gas, this liquified fluid then acts as the solvent in extracting the oil from algae. [13] Benzene, also known as C6H6, PhH, and benzol, is an organic chemical compound which is a colorless and flammable liquid with a pleasant, sweet smell. ... Ether is the general name for a class of chemical compounds which contain an ether group — an oxygen atom connected to two (substituted) alkyl groups. ... R-phrases , , , , , , S-phrases , , , , , , , Flash point −23. ... A supercritical fluid is any substance at a temperature and pressure above its thermodynamic critical point. ... Carbon dioxide is an atmospheric gas composed of one carbon and two oxygen atoms. ...


Biodiesel production from algae

www.eere.energy.govDepartment of Energy Aquatic Species Program; Biodiesel Production from Algae. (pdf)


Currently most research into efficient algal-oil production is being done in the private sector, but if predictions from small scale production experiments bear out then using algae to produce biodiesel may be the only viable method by which to produce enough automotive fuel to replace current world gasoline usage. The per unit area yield of oil from algae is at least 15 times greater than the next best crop, palm oil. Algal-oil processes into biodiesel as easily as oil derived from land-based crops. The difficulties in efficient biodiesel production from algae lie not in the extraction of the oil, which can be done using methods common to the food-industry such as hexane extraction, but in finding an algal strain with a high lipid content and fast growth rate that isn't to difficult to harvest, and a cost-effective cultivation system(ie, type of photobioreactor) that is best suited to that strain. Open-pond sytems for the most part have been given up for the cultivation of algae with high-oil content. The energy that a high-oil strain invests into the production of oil is energy that is not invested into the production of proteins or carbohydrates, usually resulting in the species being less hearty, or having a slower growth rate. Algal species with a lower oil content, not having to divert their energies away from growth, have an easier time in the harsher conditions of an open system. Research into algae for the mass-production of oil is mainly focused on microalgae,(which is a term generally referred to as organisms capable of photosynthesis that are less than 2mm in diameter), as opposed to macroalgae,(ie. seaweed). This preference towards microalgae is due largely to its less complex structure, fast growth rate, and high oil content-(for some species). Biodiesel sample Biodiesel refers to any diesel-equivalent biofuel made from renewable materials such as vegetable oils or animal fats. ... Biodiesel sample Biodiesel refers to any diesel-equivalent biofuel made from renewable materials such as vegetable oils or animal fats. ... Biodiesel sample Biodiesel refers to any diesel-equivalent biofuel made from renewable materials such as vegetable oils or animal fats. ... R-phrases , , , , , , S-phrases , , , , , , , Flash point −23. ... Figure 1: Structure of a Lipid. ... Microalgae are the most primitive form of plants. ...

  • biodieselnow.com biodiesel production-biodiesel from algae
  • europa.eu.int Biofuels production from microalgae after heterotrophic growth.(pdf)
  • (see discussion)

Algal cultures available for purchase

  • www.bio.utexas.edu/
  • www.atcc.org
  • www.ccap.ac.uk (UK)

See also

Coccolithophores are single-celled algae belonging to the haptophytes. ... Orders The taxonomy of the Cyanobacteria is currently under revision. ... Orders Dictyotales Desmerestiales Fucales Laminariales (kelps) etc. ... Diatoms are a major group of eukaryotic algae, and are one of the most common types of phytoplankton. ... The golden algae or chrysophytes are a large group of heterokont algae, found mostly in freshwater. ... Divisions Chlorophyta Charophyta Streptophytina (Subdivision) The green algae are the large group of algae from which the embryophytes (higher plants) emerged. ... Red algae Classes Florideophyceae Bangiophyceae Cyanidiophyceae The red algae are a large group of mostly multicellular, marine algae, including many notable seaweeds. ... Yellow-green algae or xanthophytes are an important group of heterokont algae. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...

External links

  • www.phyco.org; a wiki-based site that is focused on energy production from algae.
  • biodieselnow.com biodiesel production-biodiesel from algae
  • Australian freshwater algae - Sydney Botanic Gardens
  • Learn about Algae & Algal Blooms - Rural Chemical Industries (Aust.) Pty Ltd.
  • Harmful Algal Blooms - "Red tide" - National Office for Marine Biotoxins and Harmful Algal Blooms, USA.
  • Algae Section, National Museum of Natural History - Smithsonian Institution
  • www.plantphysiol.org

  Results from FactBites:
 
Algae - Wikipedia, the free encyclopedia (2842 words)
Algae have been traditionally regarded as simple plants, and indeed some are closely related to the higher plants.
Algae are usually found in damp places or bodies of water and thus are common in terrestrial as well as aquatic environments.
Algae is sometimes also used as a food, as in the Chinese "vegetable" known as fat choy (which is actually a cyanobacterium).
  More results at FactBites »

 
 

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