Haloferax mediterranei – NBRC 14739

Haloferax mediterranei

Haloferax mediterranei

Haloferax mediterranei is a halophilic archaea able to grow in high concentrations of salt. This is a well studied member of the halophilic archaea.

NBRC No. NBRC 14739
Scientific Name of this Strain Haloferax mediterranei (Rodriguez-Valera et al. 1983) Torreblanca et al. 1987
Synonymous Name
Synonym: Halobacterium mediterranei
Type Strain type
Accepted Date 1988/03/18
Isolated Year
Deposited Year
History IFO 14739 <- ATCC 33500 <- Univ. Alicante (F. Rodriguez-Valera, R-4)
Other Culture Collection No. ATCC 33500=CCM 3361=JCM 8866=VKM B-1748=DSM 1411=NCIMB 2177=IAM 13647=BCRC 15765
Other No. R-4
Rehydration Fluid 257
Medium 257
Cultivation Temp. 30 C
Oxygen Relationship
Source of Isolation Salt ponds
Locality of Source
Country of Origin Spain
Biosafety Level
Mating Type
Genetic Marker
Plant Quarantine No.
Animal Quarantine No.
Herbarium No.
References 14,15,1016
Sequences 16S rDNA
Shipping as Glass ampoule (L-dried)

>> Production of an Extracellular Polysaccharide by Haloferax mediterranei. Appl Environ Microbiol. 1988 Oct;54(10):2381-6.

The extremely halophilic archaebacterium Haloferax mediterranei produces an exocellular polymeric substance that gives the colonies a typical mucous character and is responsible for the appearance of a superficial layer in unshaken liquid medium. This exocellular polymeric substance can be obtained from the supernatant of shaken liquid cultures by cold ethanol precipitation, and yields as high as 3 mg/ml have been detected.

The substance was produced under all the conditions tested and with all substrates assayed, although higher yields were obtained with sugars, particularly glucose, as carbon and energy source. The total exocellular polymeric substance produced was proportional to the total biomass. The polymer is a heteropolysaccharide containing mannose as the major component.

Glucose, galactose, and another unidentified sugar were also present, as well as amino sugars, uronic acids, and a considerable amount of sulfate, which accounts for the acidic nature of the polymer.

The infrared spectrum and specific assays showed the absence of acyl groups. The rheological properties of polymer solutions were studied, showing a pseudoplastic behavior and a high apparent viscosity at relatively low concentrations. Viscosity was remarkably resistant to extremes of pH, temperature, or salinity. These characteristics make this polymer interesting for enhanced oil recovery and other applications for which a very resistant thickening agent is required.