Haloferax mediterranei

Natural selection, one of the key forces powering evolution, opens an array of improbable ecological niches to species that can adapt biochemically. (Left) Salt pools, where the salt concentration can be greater than 1.5 M, would seem to be highly inhospitable environments for life. Yet certain halophilic archaea, such as Haloferax mediterranei (right), possess biochemical adaptations that enable them to thrive under these harsh conditions. [(Left) Kaj R. Svensson/ Science Photo Library/Photo Researchers (right) Wanner/Eye of Science/Photo Researchers.]... 

Recently, both crenarchaeal (S. solfataricus) [99] and euryarchaeal (Haloferax mediterranei) [100] SOS ribosomes have been reconstituted. 

Abbreviations used SS, Sulfolobus solfataricus TA, Thermoplasma acidophilum DM, Desidfuro-coccus mobilis TC, Thermococcus celer TT, Thermoproleus tenax MV, Methanococcus vannielii MF, Methanobacterium formicicum HF, Haloferax mediterranei. 

It is now possible to specifically modify the individual rRNA and r-protein molecules that form the archaeal ribosome, enabling one to study the structural/functional relationships of these molecules. Recent studies on the reconstitution of the archaeal 508 ribosomal subunit from the extreme halophile Haloferax mediterranei [20] and the extreme thermophile Sulfolobus solfataricus [21] open the way for the identification of the individual functions of the r-proteins in these particles. Experiments on site-specific changes in the r-protein LI2 from Sulfolobus and their effect on the structure and function of the ribosome are described later in this chapter. 

Crude glycerol phase Biodiesel production Glycerol Haloferax mediterranei. Bacillus sphaericus, Methylobacterium rhodesianum Halorcula sp., Methylobacterium extorquens, Novosphingobium capsulatum, Cupriavidus necator. Pseudomonas oleovorans. Pseudomonas corrugata [35, 42 6)... 

Starchy waste Potato processing Starch and its hydrolysis products (maltose, glucose) Ralstonia eutropha NCIMB 11 599, A/ca//genes eutrophus Bacillus cereus Haloferax mediterranei [57-60]... 

At the moment, PHA synthesis genes of extremophiUc archaea are under detailed investigation. Haloferax mediterranei, a representative of the extreme halophilic group of the archaea branch, displays the rare ability to synthesize copolyesters of 3HB and 3HV (PHBHV) from unrelated carbon sources like sugars, hence without the need of a structurally related 3HV precursor [36, 90]. This ability saves costs normally needed for 3HV precursors. 

Lillo, J.A.G. and Rodriguez-Valera, F. (1990) Effects of culture conditions on poly (p-hydroxybutyric acid) production by Haloferax mediterranei. Applied Environmental Microbiology, 56, 2517-2521. Quillaguaman, J., Guzman, H., Van-Thuoc, D. and Kaul, R.H. (2010) Synthesis and production of polyhydroxyalkanoates by halophQes current potential and future prospects. Applied Microbiology and Biotechnology, 85,1687-1696. 

Chen, C.W., Don, T.-M. and Yen, H.-F. (2006) Enzymatic extruded starch as a carbon source for the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by Haloferax mediterranei. Process Biochemistry, 41,2289-2296. 

Roller, M.. Hesse, P.J., Bona, R. etal. (2007) Biosynthesis of high qutdity polyhydroxyalkanoate xo- and terpolyesters for potential medical application by the archaeon Haloferax mediterranei. Macromolecular Symposia. 253,33-39. 

Non-halogenated solvent extraction (antisolvent method) Haloferax mediterranei Acetone Purity 98.4% recovery 91.4% [3]... 

Huang T-Y, Duan K-J, Huang C, S-Y, Chen, W (2006) Production of polyhydroxyalkanoates from inexpensive extruded rice bran and starch by Haloferax mediterranei. J Ind Microbiol Biotechnol 33(8) 701-706... 

The third and the only other online TLC-MS approach in carotenoid analysis was presented in the study of the introduction of TiOj nanoparticles on increase of carotenoid production by the extremophilic haloarchea Haloferax mediterranei [7]. The carotenoids were extracted from bacteria and chromatographed on silica gel TLC plates developed by acetone-n-heptane (1 1, v/v). To prevent the diffusion of bands on the developed silica gel TLC plate, the area surrounding the bands was carefully scraped off prior to the addition of MALDI matrix. Based on the high-resolution mass spectra, the four colored pigments were identified as bisanhydrobac-terioruberin, monoanhydrobacterioruberin, 2-isopentenyl-3,4-dehydrorhodopin, and... 

Parolis H, Parolis LAS, Boan IF, Rodriguez-Valera F, Widmalm G, Manca MC, et al.The structure of the exopolysaccharide produced by the halophilic archaeon Haloferax mediterranei strain R4 (ATCC 33500). Carbohydr Res 1996 295 147-56. 

Other PHAscl producing strains are Pseudomonas fluorescens, Gamma proteobacterium and Haloferax mediterranei, among others. Although they present interesting results in terms of carbon source used, such as sugarcane molasses or vinasse, the productivity, PHA content in cells and yield on carbon sources are often much lower than those reported for the Cupriavidus genus (Table 2.2). 

Lillo, J. G. and Rodriguez-Valera, F. (1998). Effect of culture conditions on poly(P-hydroxybutyric acid) production by Haloferax mediterranei. Applied Microbiology 56, 2517-2521. 

Fernandez et al. (2005) reported the abihty of Pseudomonas aeruginosa to feed on fatty acids and frying oil, with a maximum production of 66% (wAv) PHA. Alias and Tan (2005) were able to obtain PHAs [54.4% (w/w)] from palm-oil-utilizing bacteria Chen et al. (2006) and Koller et al. (2007) studied production of a copolymer, PHB-co-PHV (10% HV) by an extremely halophihc archeon, Haloferax mediterranei using enzymatic extruded starch and hydrolyzed whey as a carbon source on dry cell weight basis. Ramadas et al. (2009) have reported the use of hydrolysates of agroindustrial residues as substrates for production of PHB using Bacillus sphaericus. 

Haloferax mediterranei ATCC 33500, a member of the Archaea family, was used to produce PHA using a mixture of extruded rice bran (ERB) and extruded cornstarch (ECS) as carbon source (Huang et al. 2006). This strain caimot use native rice bran or cornstarch as C-sources. By employing pH-stat control strategy in a 5-L jar bioreactor using ERB ECS (1 8 g g ) as the major carbon source, the authors obtained a cell concentration of 140 g L , PHA concentration of 77.8 g L, and PHA content of 55.6 wt% in a repeated fed-batch fermentation. Otherwise when ECS was used as the major carbon source, a 62.6 g L cell concentration, 24.2 g PHA concentration, and 38.7 wt% PHA content were achieved. ... 

Among the haloarchaea, Haloferax and Haloarcula are studied extensively for production of EPS. Haloferax mediterranei was the first haloar-chaeon to be reported for EPS. The organism is isolated from Mediterranean Sea. The EPS has complex chemical composition and can be used in oil recovery especially in oil deposits with high salinity (Anton et al., 1988 Parolis et al., 1996). Acidic EPS produced by Haloferax denitrificans has been described by Parolis et al. (1999) and EPS of Haloferax gibbonsii by Paramonov et al. (1998). Nicolaus et al. (1999) have described EPS producing Haloarcula japonica strain T5, Haloarcula sp. strain T6 and strain T7. The information on halophiles producing EPS is summarized in Table 1.2. 

Haloferax mediterranei Marine solar saltern Anton et al. (1988) Parohs et al. (1996)... 

Kamekura, M., Seno, Y., DyaU-Smith, M. Halolysin R4, a serine proteinase from the halo-philic archaeon Haloferax mediterranei gene cloning, expression and structural studies. Biochim Biophys Acta. 1996,1294, 159-167. 

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