Chlorella Beijerinck
From Greek chloros, "green"
The composition of the cell wall reveals Chlorella's ancestral pathway along three phylogenetic clades. Some researchers classify species with ellipsoidal cells, cell walls composed of a single smooth layer, and no pyrenoids as part of the genus Watanabea. Others classify species lacking pyrenoids within the genus Palmellococcus.
Chlorella is a single-celled, nonmotile green alga that is spherical or ellipsoidal in shape. The cells are usually 2-12 µm in diameter, but the size can vary, even within a single population. The cells are solitary or in irregular clumps. The chloroplasts are parietal, cup-shaped, or plate-like, and sometimes bear pyrenoids.
Chlorella has a high growth rate, which makes it very interesting to researchers in a variety of fields. Chlorella was used by Melvin Calvin to study the light-independent ("dark") photosynthetic reactions. Chlorella has the highest chlorophyll content of any known organism and has been researched for use in mass cultivation, sewage waste purification, or as bioreactors to recycle air in a closed system, such as in space. The cells are rich in proteins, vitamins, and minerals (especially B-complex vitamins) and are a potential food source. Growth farms have already been established in the United States, Japan, the Netherlands, Germany, and Israel. Chlorella is currently available as a nutritional supplement.