Chlorophyta is a taxon of green algae informally called chlorophytes. The name is used in two very different senses, so care is needed to determine the use by a particular author. In older classification systems, it is a highly paraphyletic group of all the green algae within the green plants (Viridiplantae) and thus includes about 7,000 species of mostly aquatic photosynthetic eukaryotic organisms. In newer classifications, it is the sister clade of the streptophytes/charophytes. The clade Streptophyta consists of the Charophyta in which the Embryophyta emerged. In this latter sense the Chlorophyta includes only about 4,300 species. About 90% of all known species live in freshwater. Like the land plants, green algae contain chlorophyll a and chlorophyll b and store food as starch in their plastids.
Chlorella is a genus of about thirteen species of single-celled green algae of the division Chlorophyta. The cells are spherical in shape, about 2 to 10 μm in diameter, and are without flagella. Their chloroplasts contain the green photosynthetic pigments chlorophyll-a and -b. In ideal conditions cells of Chlorella multiply rapidly, requiring only carbon dioxide, water, sunlight, and a small amount of minerals to reproduce.
The Trebouxiophyceae are a class of green algae, in the division Chlorophyta. Their circumscription within the green algae is not well established due to the need for more genetic studies at higher levels within the group.
Selenastraceae is a family of green algae in the order Sphaeropleales. Members of this family are common components of the phytoplankton in freshwater habitats worldwide. A few species have been found in brackish and marine habitats, such as in the Baltic Sea.
Auxenochlorella protothecoides, formerly known as Chlorella protothecoides, is a facultative heterotrophic green alga in the family Chlorellaceae. It is known for its potential application in biofuel production. It was first characterized as a distinct algal species in 1965, and has since been regarded as a separate genus from Chlorella due its need for thiamine for growth. Auxenochlorella species have been found in a wide variety of environments from acidic volcanic soil in Italy to the sap of poplar trees in the forests of Germany. Its use in industrial processes has been studied, as the high lipid content of the alga during heterotrophic growth is promising for biodiesel; its use in wastewater treatment has been investigated, as well.
Dictyochloropsis is a genus of unicellular green alga of the phylum Chlorophyta. This genus consists of free-living algae which have a reticulate (net-like) chloroplast that varies slightly in morphology between species, and that when mature always lacks a pyrenoid. Dictyochloropsis is asexual and reproduces using autospores.
Lagerheimia is a genus of green algae in the family Oocystaceae. It is commonly found in freshwater habitats all over the world, although some species are rare and have only been recorded from Europe or the United States.
Micractinium is a genus of green algae in the family Chlorellaceae. Species of the genus Micractinium are common in freshwater habitats. A few species are found as endosymbionts of protozoa, such as Micractinium conductrix and Micractinium tetrahymenae.
Dictyochloropsis reticulata is a species of green algae in the Trebouxiales. It is a known as a photobiont with several lichen species, like Lobaria pulmonaria, but also as a free-living soil alga as well. Phylogenetic analysis of rRNA sequence data revealed that the species shares a sister group relationship with two other green algae that lack motile stages, Chlorella saccharophila and C. luteoviridis.
The Klebsormidiaceae are a family containing five genera of charophyte green alga forming multicellular, non-branching filaments. The genus Chlorokybus was previously included as well, but this problematic and poorly known genus is now placed in a separate class Chlorokybophyceae.
Algaemia is a secondary term that refers to the emerging condition in which green algae enter the bloodstream. Members of the genus Prototheca are the most common algae that leads to algaemia. Prototheca and Chlorella, which is extremely rare, are the only two known algae genera capable of inflicting disease on mammals, including humans, through invasion of host tissue. The majority of cases are observed in dairy cattle as a cause of bovine mastitis as well as other domesticated animals. Cases of algaemia have been observed in dogs and cats as well. Few cases have been observed in humans. Human cases of algaemia or, protothecosis, are examined on a case-by-case basis due to the particularity of each case. Protothecosis infection is classified based on the symptoms: (i) cutaneous lesions, (ii) olecranon bursitis, and (iii) disseminated or systemic type infections.
Pediastrum duplex is a species of fresh water green algae in the genus Pediastrum.
Raphidonema is a genus of filamentous green alga comprising five species. It is a member of the Trebouxiophyceae.
Chlorella volutis is a species of euryhaline, unicellular microalga in the Division Chlorophyta. It is spherical to oval-shaped, is solitary and lacks a mucilaginous envelope.
Chlorella rotunda is a euryhaline, unicellular microalga in the Division Chlorophyta. It is spherical to oval-shaped, is solitary and lacks a mucilaginous envelope.
Chlorella lewinii is a euryhaline, unicellular microalga in the Division Chlorophyta. It is spherical to oval-shaped, is solitary and lacks a mucilaginous envelope.
Chlorella pulchelloides is a species of euryhaline, unicellular microalga in the Division Chlorophyta. It is spherical to oval-shaped and is solitary
Chlorella pituita is a species of euryhaline, unicellular microalga in the Division Chlorophyta. It is spherical to oval-shaped and is solitary
Chlorella coloniales is a euryhaline, unicellular microalga in the Division Chlorophyta. It is spherical to oval-shaped and is solitary
Chlorellosis is a disease caused by the infection of Chlorella, a type of microalgae containing large amount of chloroplasts. It is mainly found in sheep and cattle, while cases in humans, dogs, antelopes, beavers, camels and fish, were also reported. Symptoms of Chlorellosis including focal cutaneous lesions, lymphadenitis, and peritonitis.
