Chlorella pyrenoidosa is a species of the freshwater green algae genus "Chlorella". Chlorella is a genus of single-celled green algae belonging to the division Chlorophyta. The bacterium attaches to the surface of green algae of the genus "Chlorella". Vitamin B12, specifically in the form of methylcobalamin, has been identified in "Chlorella vulgaris". In addition, "Chlorella" contains fat and vitamins. In these experiments, monocellular Chlorella were cultivated by adding CO and some minerals. When first harvested, "Chlorella" was suggested as an inexpensive protein supplement to the human diet. Zoochlorella is a "nomen rejiciendum" for a genus of green algae assigned to "Chlorella". Methylcobalamin has been identified in "Chlorella vulgaris". "Chlorella" has only a niche market for companies promoting it as a dietary supplement. " strain in culture with "Chlorella vulgaris. "Chlorella" can be a nuisance organism in freshwater aquaria. The enzyme has been found in "Chlorella variabilis". Bendix (1964) also observed that "Chlorella" produces motile cells which might be gametes. To achieve a balance of oxygen and carbon dioxide, one human needed of exposed Chlorella.