The Potential Biotechnological Applications of the Exopolysaccharide Produced by the Halophilic Bacterium Halomonas almeriensis Llamas Company, Inmaculada Amjres, Hakima Mata Gómez, Juan Antonio Quesada Arroquia, Emilia Béjar Luque, María Victoria Extremophiles Halophilic bacteria Halomonas almeriensis Exopolysaccharide Sulphates Heavy-metal chelation Emulsifying activity We have studied the extracellular polysaccharide (EPS) produced by the type strain, M8T, of the halophilic bacterium Halomonas almeriensis, to ascertain whether it might have any biotechnological applications. All the cultural parameters tested influenced both bacterial growth and polysaccharide production. EPS production was mainly growth-associated and under optimum environmental and nutritional conditions M8T excreted about 1.7 g of EPS per litre of culture medium (about 0.4 g of EPS per gram of dry cell weight). Analysis by anion-exchange chromatography and high-performance size-exclusion chromatography indicated that the exopolysaccharide was composed of two fractions, one of 6.3 × 106 and another of 1.5 × 104 Daltons. The monosaccharide composition of the high-molecular-weight fraction was mannose (72% w/w), glucose (27.5% w/w) and rhamnose (0.5% w/w). The low-molecular-weight fraction contained mannose (70% w/w) and glucose (30% w/w). The EPS has a substantial protein fraction (1.1% w/w) and was capable of emulsifying several hydrophobic substrates, a capacity presumably related to its protein content. The EPS produced solutions of low viscosity with pseudoplastic behaviour. It also had a high capacity for binding some cations. It contained considerable quantities of sulphates (1.4% w/w), an unusual feature in bacterial polysaccharides. All these characteristics render it potentially useful as a biological agent, bio-detoxifier and emulsifier. 2013-10-23T09:36:55Z 2013-10-23T09:36:55Z 2012 info:eu-repo/semantics/article Llamas, I. ; et al. The Potential Biotechnological Applications of the Exopolysaccharide Produced by the Halophilic Bacterium Halomonas almeriensis, 17(6): 7103-7120 (2012). [doi: 10.3390/molecules17067103] 1420-3049 http://hdl.handle.net/10481/28518 10.3390/molecules17067103 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ info:eu-repo/semantics/openAccess Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License MDPI