 | |||||||||||||||||||||||||
BeijerinckiaRANK: GenusTAXONOMY: cellular organisms -> Bacteria -> Proteobacteria -> Alphaproteobacteria -> Rhizobiales -> Beijerinckiaceae -> Beijerinckia OVERVIEW: Straight or slightly curved rods, ~0.5–1.5 × 7–4.5 μm, with rounded ends. Cells occur singly or appear as dividing pairs. Sometimes large, misshapen cells 3.0 × 5.0–6.0 µm occur; these are occasionally branched or forked. Intracellular granules of poly-β-hydroxybutyrate (PHB) are formed, generally one at each pole. Cysts (enclosing one cell) and capsules (enclosing several cells) may occur in some species. Gram negative. Motile by peritrichous flagella or nonmotile. Aerobic, having a strictly respiratory type of metabolism. N2 is fixed under aerobic or microaerobic conditions. Optimal temperature for growth, 20–30°C; no growth occurs at 37°C. Growth occurs between pH 3.0 and pH 9.5–10.0. Liquid cultures can become a highly viscous, semitransparent mass; in some species the whole medium becomes opalescent and turbid, and adhering slime is not produced. On agar media, especially under N2-fixing conditions, copious slime is produced and giant colonies with a smooth, folded, or plicate surface develop; some strains form slime having a more granular consistency. Catalase positive. Glucose, fructose, and sucrose are utilized by all strains and oxidized to CO2. No growth occurs on peptone medium. Glutamate is utilized poorly or not at all. Species are found in soils, particularly tropical regions.The mol% G + C of the DNA is: 54.7–60.7.Type species: Beijerinckia indica
| |||||||||||||||||||||||||