Fla.vo.bac.te'ri.um. L. adj.
flavus
yellow; L. neut. n.
bacterium
a rod or staff and, in biology, a bacterium (so called because the first ones observed were rod‐shaped); N.L. neut. n.
Flavobacterium
a yellow bacterium.
Bacteroidetes / Flavobacteriia / Flavobacteriales / Flavobacteriaceae / Flavobacterium
Straight or slightly curved, single rods
with rounded or slightly tapered ends typically about 0.3–0.5 µm in diameter and variable in length, often 2–5 µm; shorter (1 µm) or filamentous (10–40 µm) cells and pleomorphism also occur. The longer rods are flexible. Do not form endospores. Several species produce spherical degenerative forms (spheroplasts) in stationary growth phase.
Nonmotile or motile by gliding. Flagella have not been reported. Colonies are pale to bright yellow due to the production of nondiffusible, nonfluorescent carotenoid or flexirubin types of pigments or both
. Gram‐stain‐negative. Chemoorganotrophic.
Most species are obligately aerobic, having a strictly respiratory type of metabolism
with oxygen as the terminal electron acceptor. A few species may also grow weakly under microaerobic to anaerobic conditions.
About half of the species are able to reduce nitrate to nitrite, but only one species is able to carry out complete denitrification
. The optimum growth temperature range is 20–30°C for most temperate species and 15–20°C for most cold‐living species. Most species grow readily on nutrient and tryptic soy agars; no growth factors are required. Most species also grow on media containing up to 2–4% NaCl.
Usually positive for catalase and oxidase
. About half of the species are able to oxidize carbohydrates. Esculin and starch are hydrolyzed by most species, but agar and carboxymethylcellulose are hydrolyzed by only a few species. Strong proteolytic activity occurs. Menaquinone MK‐6 is the only or predominant respiratory quinone. Predominant cellular fatty acids are C
15:0
, C
15:0
iso, C
15:0
iso 3‐OH, C
15:0
anteiso, C
15:1
ω6
c
, C
15:1
iso
G
, C
16:0
iso 3‐OH, and C
17:0
iso 3‐OH, as well as C
15:0
iso 2‐OH and/or C
16:1
ω7
c
and/or C
16:1
ω7
t
. Sphingophospholipids are absent in all tested species. Homospermidine is the major polyamine in all tested species.
Occur in soil and in freshwater, marine, or saline environments in warm, temperate, or polar locations. Three species are pathogenic for freshwater fish
and three others have occasionally been isolated from diseased freshwater fish.
DNA G
+
C content
(
mol
%): 30–41.
Type species
:
Flavobacterium aquatile
(Frankland and Frankland 1889) Bergey, Harrison, Breed, Hammer and Huntoon 1923, 100 (
Bacillus aquatilis
Frankland and Frankland 1889, 381) (not
Flavobacterium antarcticum
as erroneously printed in Bernardet and Bowman, 2006).