Ha.lo.ru'brum
. Gr. n.
hals
,
halos
, salt; L. neut. adj.
rubrum
, red; N.L. neut. n.
Halorubrum
salt (‐requiring) and red.
Euryarchaeota / Halobacteria / Haloferacales / Halorubraceae / Halorubrum
With 37 species,
Halorubrum
(family
Halorubraceae
, order
Haloferacales
) is the largest genus within the class
Halobacteria
. Cells of
Halorubrum
species are rod shaped or pleomorphic under optimal growth conditions and stain Gram‐negative. Some species are motile. Colonies are generally red‐orange due to the presence of bacterioruberin carotenoids, but some species are almost colorless; retinal pigments can also be present. Some strains produce gas vesicles.
Halorubrum
species are extremely halophilic, with growth occurring in media containing 1.0–5.2 M NaCl; the optimum magnesium concentration varies between 0.005 and 0.6 M. Cells lyse in distilled water. The genus contains both neutrophilic and alkaliphilic species. All are aerobic chemoorganotrophs; anaerobic growth of some species was reported in the presence of nitrate or arginine. Some species grow on single carbon sources. Most species use sugars, some with the production of acids. The major polar lipids are C
20
C
20
and sometimes C
20
C
25
glycerol diether derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate (in most species), and a sulfated glucosyl mannosyl diether, for some species identified as S‐DGD‐3. Alkaliphilic species lack glycolipids. The DNA G + C content is between 60.2 and 71.2 mol%.
Halorubrum
species have been isolated from marine salterns, salt lakes, soda lakes, saline soils, rock salt, salted foods, and other hypersaline environments. The type species is
Halorubrum saccharovorum
.
Later homotypic synonym:
Halorubrobacterium
Kamekura and Dyall‐Smith 1996, 625
VP
(Effective publication: Kamekura and Dyall‐Smith 1995, 345).
DNA G + C content (mol%)
: 60.2–71.2.
Type species
:
Halorubrum saccharovorum
(Tomlinson and Hochstein 1976) McGenity and Grant 1996, 362
VP
(Effective publication: McGenity and Grant 1995, 241) (
Halobacterium saccharovorum
Tomlinson and Hochstein 1977, 306;
Halorubrobacterium saccharovorum
(Tomlinson and Hochstein 1976) Kamekura and Dyall‐Smith 1996, 625).