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ZoogloeaRANK: GenusTAXONOMY: cellular organisms -> Bacteria -> Proteobacteria -> Betaproteobacteria -> Rhodocyclales -> Rhodocyclaceae -> Zoogloea OVERVIEW: The following description is representative of the genus based on well-characterized isolates recovered directly from naturally occurring, typical, fingered zoogloeae: Straight to slightly curved, plump rods, 1.0–1.3 × 2.1–3.6 µm, with rounded ends; sometimes tapered to a blunt point at one or both poles. Nonsporeforming and noncystforming. Cells in older cultures are demonstrably encapsulated. Gram negative. Actively motile, especially in young cultures, by means of a single polar flagellum. Intracellular granules of poly-β-hydroxybutyrate are formed on media containing the salts of organic acids. Cultures enter into formation of flocs and films in liquid media at late growth stages; the cells become embedded in gelatinous matrices to form zoogloeae, which may be distinguished by a “tree-like” or “finger-like” morphology. Young colonies on solid media under a normal air atmosphere are translucent and punctiform, but may increase to 1 or 2 mm in diameter and exhibit opaque centers. Nonpigmented. Aerobic, having a strictly respiratory type of metabolism with oxygen or nitrate as the terminal electron acceptor. Denitrification occurs with formation of N2. Optimal temperature for growth, 28–37°C. Optimal pH, 7.0–7.5. Oxidase positive. Weakly catalase positive. Chemoorganotrophic. Acid is not formed from carbohydrates except for xylose, glycerol, and ethanol, which are attacked oxidatively by a few strains. Proteolytic on gelatin. Most strains are urease positive. Litmus milk is unchanged. Hydrogen sulfide is usually not produced from cysteine. Major carbon sources include salts of several organic acids (e.g., lactate, pyruvate, and fumarate), dicarboxylic amino acids (e.g., aspartate, glutamate, and asparagine), alcohols, and salts of certain aromatic acids (e.g., benzoate and m-toluate). Benzene derivatives are attacked by meta cleavage of the ring structure. Organic nitrogen compounds (e.g., dicarboxylic amino acids) and ammonia serve as nitrogen sources; nitrate is unsuitable. Specific growth factor requirements, if any, are unknown. Major cellular fatty acids are palmitoleic (C16:1) and 3-hydroxydecanoic (C10:0 3OH) acids. Major respiratory quinones are Q-8 and RQ-8. The major polyamine is 2-hydroxyputrescine. Occur free-living in organically polluted fresh waters and in wastewaters at all stages of treatment.The mol% G + C of the DNA is: 67.3–69.0.Type species: Zoogloea ramigera
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