Methylovorus

Abstract

Me . thyl . o ' vo . rus . Fr. méthyle the methyl radical; L. v. voro to consume; M.L. adj. methylovorus methylconsuming. Proteobacteria / Betaproteobacteria / Methylophilales / Methylophilaceae / Methylovorus When grown on methanol–mineral salts medium , cells are straight or slightly curved rods , usually 0.5–0.6 × 1.0–1.3 µm, occurring singly or in pairs. Gram negative. Motile by a single polar flagellum. Endospores are absent. No complex intracellular membranes. No sheaths or prosthecae detected. No capsules formed, but slime may be produced by some strains. Colonies on methanol–mineral salts agar incubated for 2 days at 30°C are circular, 1–2 mm in diameter, with entire edge, convex, and translucent to opaque; may be pink, creamy, or milky in color. Pyocyanin and fluorescein not produced. Cells multiply by binary fission. No aggregation or pigmentation occurs in liquid medium. No growth or extremely poor growth occurs on nutrient agar and in nutrient broth at 30–37°C; no growth occurs under an atmosphere of CH 4 /O 2 or H 2 /CO 2 /O 2 . Optimal pH for growth, 7.0–7.2; temperature, 35–37°C. Aerobic , having a strictly respiratory type of metabolism with oxygen as the terminal electron acceptor. Only methanol and glucose are used as carbon and energy sources . In addition, some strains are able to grow slowly on methylated amines and betaine. Nitrates, ammonium salts, methylated amines, glutamate, and peptone serve as nitrogen sources. Acetoin, indole, H 2 S, and NH 3 are not produced in test medium. Milk is not hydrolyzed. Oxidase positive . Urease and catalase positive. Peroxidase variable. Arginine dihydrolase negative. Strains may hydrolyze starch, but not cellulose, gelatin, or Tween 80. Acid, but not gas, is produced from glucose. Isolated from activated sludge, mud, soil, and pond water. The mol % G + C of the DNA is : 56–57. Type species : Methylovorus glucosotrophus Govorukhina and Trotsenko 1991, 162.