Study On Extracellular Polysaccharide Of Antarctic Psychrotrophs Pseudoalteromonas Sp. S-15-13

The Antarctic marine environment is perennially cold; in some cases it is permanently ice-covered. Spatial heterogeneity, combined with extreme seasonal fluctuations such as those experienced during annual sea-ice formation events, results in a high diversity of microbial habitats and therefore microbial communities.Extreme environments are proving to be a valuable source of microorganisms that secrete interesting new molecules, including exopolysaccharides. Microbial EPSs are abundant in the Antarctic marine environment, exopolymer production by both microalgae and bacteria contributes to organic carbon in the sea-ice and ice water interface. The EPS present in very high concentrations in the brine of these microhabitats appear to play important buffering and cryoprotectant roles for microorganisms against harsh winter conditions of high salinity, pH, potential ice-crystal and other chemical substances damage.Ecologic studies examining the role of EPSs in marine habitats now provide evidence that these substances are abundant in the Antarctic marine environment. However, few studies focusing on the biotechnological potential of EPSs produced by bacteria from the Antarctic marine environment have been reported in the literature to date. Therefore a wide search for microrganisms able to produce good yields of new polysaccharides with potentially useful properties has been undertaken, also involving extremophiles because they have potent biological and pharmacological activities, including immunostimulating, antitumour, and hypoglycaemic activity. So, Bacteria collected by CTD during Chinese 19th Antarctic Scientific Expedition in the Southern Ocean between January and February in 2002 were studied. Out of 57 strains of Antarctic marine bacteria, 27 were found to produce EPS according to the staining technique. Phylogenetic tree...