ISSN:
1432-072X
Keywords:
Key words: Halophilic Archaea –Haloferax– Aromatic-ring mineralization – Benzoate – Cinnamate – Phenylpropanoate – Oil brine
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract. A pink-pigmented halophilic Archaeon, Strain D1227, was isolated from soil contaminated with oil brine and shown to be a member of the genus Haloferax, based on: (1) its hybridization with a 16S rRNA probe universal for the Archaea; (2) its resistance to a broad spectrum of antibiotics that affect Bacteria; (3) its requirement for at least 0.86 M NaCl and 25 mM Mg2+ for growth; (4) its possession of C50-carotenoids characteristic of the halophilic Arachaea; (5) the thin layer chromatographic pattern of its polar lipids, which was identical to that of other species of Haloferax; and (6) its pleomorphic cell morphology. However, in contrast to the known species of Archaea, Haloferax strain D1227 was able to use aromatic substrates (e.g., benzoate, cinnamate, and phenylpropanoate) as sole carbon and energy sources for growth. Physiologically similar organisms, such as Haloferax volcanii, Haloferax mediterrani, Haloarcula vallismortis, and Haloarcula hispanica, could not grow on these aromatic substrates. When grown on 14C-benzoate, strain D1227 mineralized 70% of the substrate and assimilated 19% of the 14C-label into cell biomass. In addition to growth on aromatic substrates, D1227 was also capable of growth on a variety of carbohydrates and organic acids. Optimum growth of strain D1227 occurred at 45°C in media containing 1.7 – 2.6 M NaCl and 100 mM Mg2+. Under optimum growth conditions, the cell shape varied from that of an oblate spheroid on mineral salts medium alone, to disc-shaped, irregular or triangular cells on the same medium amended with yeast extract and tryptone. To our knowledge, this is the first unequivocal demonstration of the ability of an Archaeon to grow by mineralization of aromatic substrates, and it adds a new dimension to our appreciation of the physiological diversity of this group of prokaryotes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00307764
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