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The structure of the exopolysaccharide produced by Alteromonas macleodii subsp. fijiensis recovered from a deep-sea hydrothermal vent has been investigated. By means of chemical analysis and NMR studies, the repeating unit of the polymer was deduced to be a branched hexasaccharide with the structure shown. [formula]

structural, uronic acid, exopolysaccharide, Bacterial polysaccharide, structural studies, pyruvate, Mannose, Alteromonas, hydrothermal, hydrothermal vent, Alteromonas macleodii, pyruvic acetal residue

NCBI PubMed ID: 9836450
Journal NLM ID: 0043535
Publisher: Elsevier
Institutions: Complex Carbohydrate Center, University of Georgia, Athens, GA 30602-4712, USA, Groupe EVEN, BP 67, 29260 Ploudaniel, France, Ifremer, Centre de Brest, DRV/VP BMH, BP 70, 29280 Plouzanea, France
Methods: 13C NMR, 1H NMR, methylation, GLC-MS, b-elimination, composition analysis

The marine environment is the largest aquatic ecosystem on Earth and it harbours microorganisms responsible for more than 50% of total biomass of prokaryotes in the world. All these microorganisms produce extracellular polymers that constitute a substantial part of the dissolved organic carbon, often in the form of exopolysaccharides (EPS). In addition, the production of these polymers is often correlated to the establishment of the biofilm growth mode, during which they are important matrix components. Their functions include adhesion and colonization of surfaces, protection of the bacterial cells and support for biochemical interactions between the bacteria and the surrounding environment. The aim of this review is to present a summary of the status of the research about the structures of exopolysaccharides from marine bacteria, including capsular, medium released and biofilm embedded polysaccharides. Moreover, ecological roles of these polymers, especially for those isolated from extreme ecological niches (deep-sea hydrothermal vents, polar regions, hypersaline ponds, etc.), are reported. Finally, relationships between the structure and the function of the exopolysaccharides are discussed.

NMR, capsular polysaccharide, exopolysaccharide, exopolysaccharides, EPS, purification, Extremophile, marine, chemical characterization, GC-MS, structure/activity relationship

NCBI PubMed ID: 29461505
Publication DOI: 10.3390/md16020069
Journal NLM ID: 101213729
Publisher: Basel, Switzerland: Molecular Diversity Preservation International
Correspondence: corsaro@unina.it; angela.casillo@unina.it
Institutions: Department of Chemical Sciences, University of Naples 'Federico II', Naples 80126, Italy

Polysaccharides and, in particular, microbial polysaccharides represent a class of important products of growing interest for many sectors of industry. Although many known marine bacteria produce exopolysaccharides (EPS), continuation in looking for new polysaccharide-producing microorganisms is promising. Hydrothermal deep-sea vents could be a source of novel EPS as indicated by the screening of a number of mesophilic heterotrophic bacteria recovered from different locations. Although originating from such extreme environment, some bacteria were shown to biosynthesize innovative EPS under laboratory conditions. Their specific rheological properties either in the presence or absence of monovalent and divalent ions, biological activities, metal binding capabilities, and novel chemical composition mean that these EPS are expected to find many applications in the near future

Bacterial exopolysaccharides, hydrothermal vents

NCBI PubMed ID: 12355321
Publication DOI: 10.1038/sj.jim.7000298
Journal NLM ID: 9705544
Institutions: IFREMER, Centre de Brest, Dept. DRV/VP/BMM, Plouzane, France

Exopolysaccharides (EPSs) are high molecular weight carbohydrate polymers that make up a substantial component of the extracellular polymers surrounding most microbial cells in the marine environment. EPSs constitute a large fraction of the reduced carbon reservoir in the ocean and enhance the survival of marine bacteria by influencing the physicochemical environment around the bacterial ce11. Microbial EPSs are abundant in the Antarctic marine environment, for example, in sea ice and ocean particles, where they may assist microbial communities to endure extremes of temperature, salinity, and nutrient availability. The microbial biodiversity of Antarctic ecosystems is relatively unexplored. Deep-sea hydrothermal vent environments are characterized by high pressure, extreme temperature, and heavy metals. The commercial value of microbial EPSs from these habitats has been established recently. Extreme environments offer novel microbial biodiversity that produces varied and promising EPSs. The biotechnological potential of these biopolymers from hydrothermal vent environments as well as from Antarctic marine ecosystems remains largely untapped

Bacterial exopolysaccharides, hydrothermal vents

NCBI PubMed ID: 16075348
Publication DOI: 10.1007/s10126-004-5118-2
Journal NLM ID: 100892712
Correspondence: C.A.Mancuso@utas.edu.au
Institutions: School of Agricultural Science, University of Tasmania, Hobart, Australia, Institute Français de Recherche pour l’Exploitation de la Mer, Centre de Brest, DRV/VP, Plouzané, France, Australian Centre of Excellence for Food Safety, University of Tasmania, Hobart, Australia