Rho.do.ther'mus. Gr. n.
rhodon
rose; Gr. masc. adj.
thermos
hot; N.L. masc. n.
Rhodothermus
the red thermophile.
Bacteroidetes / Cytophagia / Incertae sedis II / Rhodothermaceae / Rhodothermus
Straight rods
about 0.5 × 2.0–2.5 µm, with curved ends.
Occur singly
,
never in chains or filaments
.
Nonmotile
. Gram‐stain‐negative. A slime capsule is formed on carbohydrate‐rich medium.
Most strains form red colonies
, due to a carotenoid pigment. Colonies are low convex, 3–4 mm in diameter with an entire edge.
Aerobic
.
Thermophilic
,
growing at 54–77
°
C
. Neutrophilic. Heterotrophic.
Growth is strictly salt‐dependent
,
occurring in the range of 0
.
6 to
>
6
%
NaCl
. Catalase‐positive. The oxidase reaction varies among strains. No dissimilatory nitrate reduction occurs.
Growth occurs on most common sugars
. The major cellular fatty acids are C
15
iso, C
15
anteiso, C
17
iso and C
17
anteiso. The major quinone is menaquinone 7. The habitat is submarine freshwater alkaline hot springs, marine hot springs, geothermal sites, and borehole effluents.
DNA G
+
C content
(
mol
%): 64–66 (
T
m
).
Type species
:
Rhodothermus marinus
Alfredsson, Kristjansson, Hjörleifsdottir and Stetter 1995, 418
VP
(Effective publication: Alfredsson, Kristjansson, Hjörleifsdottir and Stetter 1988, 304;
Rhodothermus obamensis
Sako, Takai, Ishida, Uchida and Katayama 1996, 1103.).