''Botryococcus'' is a genus of

green algae The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ...

. It is a microscopic or semi-microscopic alga that is found in freshwater habitats worldwide. It consists of colonies of cells in an irregular, gelatinous matrix. ''Botryococcus'' produces high amounts of oil, which often make the colonies colored yellowish to reddish. When seen with a

microscope A microscope () is a laboratory equipment, laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic ...

, colonies release oil under the pressure of a

cover slip A microscope slide is a thin flat piece of glass, typically 75 by 26 mm (3 by 1 inches) and about 1 mm thick, used to hold objects for examination under a microscope. Typically the object is #Mounting, mounted (secured) on the slide, ...

. Because of its high amounts of oil, ''Botryococcus'' is of interest to the field of

biotechnology Biotechnology is a multidisciplinary field that involves the integration of natural sciences and Engineering Science, engineering sciences in order to achieve the application of organisms and parts thereof for products and services. Specialists ...

, as it is a promising source of

biofuel Biofuel is a fuel that is produced over a short time span from Biomass (energy), biomass, rather than by the very slow natural processes involved in the formation of fossil fuels such as oil. Biofuel can be produced from plants or from agricu ...

. In addition to its current biosynthetic capabilities, fossils of the genus are known since

Precambrian The Precambrian ( ; or pre-Cambrian, sometimes abbreviated pC, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of t ...

times, and form the single largest biological contributor to

crude oil Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring u ...

, and are a major component of

oil shale Oil shale is an organic-rich Granularity, fine-grained sedimentary rock containing kerogen (a solid mixture of Organic compound, organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general compos ...

Taxonomy

The genus and its holotype were described in 1849 by

Friedrich Traugott Kützing Friedrich Traugott Kützing (8 December 1807 in Ritteburg – 9 September 1893) was a German pharmacist, botanist and phycologist. Despite his limited background in regard to higher education, Kützing made significant scientific contribution ...

Description

''Botryococcus'' consists of irregularly shaped colonies of cells; in some species or when old, the colonies may be composed of subcolonies connected by gelatinous strands. Cells are 6-20 μm long and 2.5-8 μ wide, elongate, obovoid and narrower near the center of the colonies, ovoid, or spherical, and arranged around the periphery of the colony in one layer. They are partially or wholly submerged in a gelatinous matrix, or may be attached to the gelatinous matrix at the base. The matrix is often impregnated with oil that gives the colony a yellowish, brownish or reddish color. Cells are uninucleate (with one

nucleus Nucleus (: nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom *Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucleu ...

) and contain a single parietal, cup-shaped

chloroplast A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which captur ...

with one

pyrenoid Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae,Giordano, M., Beardall, J., & Raven, J. A. (2005). CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution. ''An ...

(but the pyrenoid may not be visible due to oil droplets crowding the protoplast). Reproduction in ''Botryococcus'' occurs asexually by the formation of

autospore Autospores are a type of spores that are produced by algae to enable asexual reproduction and spread. They are non-motile and non-Flagellated cell, flagellated Aplanospore, aplanospores that are generated within a parent cell and have the same sha ...

s. The protoplast divides into two, four, eight or 16 autospores, while the parent cell walls gelatinize. Sexual reproduction and zoospores have not been reported in this genus.

Ecology

The algae is frequently found in plankton in waters with differing characteristics and a wide geographic distribution. It is an important component of algal blooms and the discoloration of water.

Species

There are 13 accepted species in the genus. *'' Botryococcus australis'' *'' Botryococcus balkachicus'' *''

Botryococcus braunii ''Botryococcus braunii'' is a green, pyramid-shaped planktonic microalga that is of potentially great importance in the field of biotechnology. Until 2024 it was considered to have three races: A, B, and L., but it was then determined that these ...

'' *''

Botryococcus calcareus ''Botryococcus'' is a genus of green algae. It is a microscopic or semi-microscopic alga that is found in freshwater habitats worldwide. It consists of colonies of cells in an irregular, gelatinous matrix. ''Botryococcus'' produces high amounts ...

'' *'' Botryococcus canadensis'' *'' Botryococcus comperei'' *'' Botryococcus fernandoi'' *'' Botryococcus neglectus'' *'' Botryococcus pila'' *'' Botryococcus protuberans'' *'' Botryococcus pusillus'' *'' Botryococcus terribilis'' *'' Botryococcus terricola'' Species-level delimitation of ''Botryococcus'' remains difficult. Species are distinguished by morphological characters such as the cell size, shape, and characteristics of the mucilage. However, the morphological characters may overlap and it is sometimes not possible to assign a population to a species.

References

{{Taxonbar, from=Q894818 Trebouxiophyceae genera Trebouxiales Taxa named by Friedrich Traugott Kützing Freshwater algae