Micractinium

Micractinium is a genus of microscopic green algae in the family Chlorellaceae. Species of the genus Micractinium are found as phytoplankton, and are commonly found in freshwater habitats around the world. A few species are found as endosymbionts of ciliates. There is increasing interest in Micractinium due to its high growth rate and lipid production.

==Description== Cells of Micractinium are spherical to ellipsoidal, and are solitary or stuck together in colonies. Colonies can contain up to 128, occasionally 256 cells, and are polyhedral or pyramidal in shape. Most species generally produce long narrow bristles that taper from base to tip. Cells have a single cup-shaped chloroplast with a single pyrenoid. Bristles consist of protein and lack cellulosic fibers; they are produced after the cell wall.