A.na.e.ro.plas'ma. Gr. prefix an without; Gr. masc. n. aer air; Gr. neut. n. plasma a form; N.L. neut. n. Anaeroplasma intended to denote “anaerobic mycoplasma”.

Tenericutes / Mollicutes / Anaeroplasmatales / Anaeroplasmataceae / Anaeroplasma

Cells are predominantly coccoid, about 500 nm in diameter; clusters of up to ten coccoid cells may be joined by short filaments. Older cells have a variety of pleomorphic forms. Cells lack a cell wall and are bound by a single plasma membrane. Gram-stain-negative due to absence of cell wall. Obligately anaerobic; the inhibitory effect of oxygen on growth is not alleviated during repeated subcultures. Require sterol supplements for growth. Nonmotile. Optimal temperature, 37°C; no growth at 26 or 47°C. Optimal pH, 6.5–7.0. Surface colonies have a dense center with a translucent periphery, or “fried-egg” appearance. Subsurface colonies are golden, irregular, and often multilobed. Strains vary in their ability to ferment various carbohydrates. The products of carbohydrate fermentation include acids (generally acetic, formic, propionic, lactic, and succinic), ethanol, and gases (primarily CO₂, but some strains also produce H₂). Bacteriolytic and nonbacteriolytic strains have been described. Commensals in the bovine and ovine rumen.

DNA G+C content (mol%): 29–34 (T _m, Bd).

Type species: Anaeroplasma abactoclasticum Robinson, Allison and Hartman 1975, 179^AL.