Polysaccharides from microorganisms

Examples of polysaccharides from microorganisms dextran, gellan gum, pullulan, xanthan gum, and bacterial cellulose. 

The number of enzymes responsible for the formation of polysaccharides from sucrose is also restricted. The two best known enzymes that form polysaccharides from sucrose are the dextran, synthesized by the microorganism Leuconostoc mesenteroides (8) and related organisms, and the levan, produced from the same substrate by Acetobacter levanicum (9) and other species. 

As regards the antiviral compounds derived from microorganisms, the polysaccharides nostoflan and naviculan proved to be active against influenza A virus [54,97]. Chemically synthesized oversulfated derivatives of extracellular GAG and SP, produced by a marine Pseudomonas, prepared by dicyclohexylcarbodiimide-mediated reaction for both polysaccharides, showed antiviral activities against influenza virus type A but not against type B [52],... 

Specific enzymatic degradation has been useful in determining the structures of pectins, gums and other plant polysaccharides (115), the mucopolysaccharides of higher animals (116), and other complex carbohydrates (117) including those from microorganisms 118, 119, 120). In these heterogeneous polymers enzyme treatment is most useful for deter-... 

A significant amount of work also has been done on direct Py-MS of a variety of microorganisms with the purpose of their rapid identification and classification [3]. separation of the polysaccharide from the whole microorganism was done for this purpose, but the polysaccharide pyrolysis products are main components of the pyrolysate. Some of these applications are described in Part 3 of this book. 

Bacterial polysaccharides can also serve as markers to identify specific bacterial species or genera. Typical microbial polysaccharides include peptidoglycans, lipopolysaccharides, and teichoic/teichuronic acids. Some markers such as muramic acid, D-alanine, and p-hydroxy myristic acid are present in the polysaccharides from eubacteria but are uncommon in higher life forms such as plants and animals. Pyrolysis results on bacterial polysaccharides were discussed in Sections 7.9 and 7.10. Specific pyrolysis products such as propionamide or peaks characteristic for KDO have been used for Py-MS or Py-GC/MS characterization of microorganisms. 

Levan has a backbone of p-(2 6) linked o-fructose and occurs as high molecular weight polysaccharide in microorganisms. It is accessible from sucrose by use of the enzyme levansucrase (sucrose 6-fructosyltransferase (FTF, EC 2.4.1.10)). Either culture broth of bacterial strains like Bacillus or Zymomonas or the cell-free supernatant can be used for the enzymatic reaction with sucrose. The molecular weight and the viscosity of levan depend on the strain used and the reaction conditions [131, 134]. Even though levan has interesting properties, it has never gained extensive industrial use up to now [134]. 

Yoo S-H, Yoon E J, Cha J, et al. (2004). Antitumor activity of levan polysaccharides from selected microorganisms. Internat. J. Biol. Macromol. 34 37-41. 

Bacterial polysaccharides present a real potential in cell therapy and tissue engineering with the advantage, over the polysaccharides from eukaryotes, that they can be totally produced under controlled conditions in bioreactors. Polysaccharides synthesized by microorganisms suggest unique properties and advantages in their exploration and are an attractive alternative of plant, algal and synthetic polysaccharides. They represent a fast renewable resource that could partially compensate the restricted mass of plant polysaccharides. Their production is a matter of days, while plants life cycles last for months or years, being that the production cycle is usually... 

A limited amount of gram-positive bacteria (Streptococcus sp. and Pasteurella sp.) are able to synthesize a polysaccharide from the upper capsule (1 mm thick) they create [31,32]. The majority of such microorganisms are pathogenic to humans and animals, but they are also able to parasite in the intercellular space of the mammal s tissue. That is why there is high demand for these microorganisms ... 

Xanthan gum, the extracellular polysaccharide from Xanthomonas campestris and some related microorganisms, is produced on a nutritive medium containing glucose, NH4CI, a mixture of amino acids, and minerals. The polysaccharide is recovered from the medium by isopropanol precipitation in the presence of KCl. 

The method has proved valuable in studies of the carbohydrate metabolism of microorganisms (105,106), sucrose utilization by fungi (87) and bacteria (22,26), and microbial polysaccharides, e. g., the carbohydrates in yeast cell wall (194,238), polysaccharides of soils (86,104), and polysaccharides from tuberculin and pneumococcus type II (157). 

Nicolaus B, Lama L, Panico A, Schiano-Moriello V, Romano I, Gambacorta A (2002) Production and characterization of exopolysaccharides excreted by thermophilic bacteria from shallow, marine hydrothermal vents of flegrean areas (Italy). Syst Appl Microbiol 25 319-325 Nicolaus B, Schiano-Moriello V, Lama L, Poll A, Gambacorta A (2004) Polysaccharides from extremophilic microorganisms. Orig Life Evol Biosph 34 159-169... 

Manufacturing method Obtained by separating the polysaccharides released from microorganism Xanthomonas campestris. 

Many polysaccharides contain branched structures and are chemically modified by the addition of other molecules. Their monomeric or repeat units are often made up of more than one sugar molecule and, consequently, can be quite complex. They form protective capsules of some of the most virulent microorganisms, capsules that, nevertheless, carry information that activate mammalian defenses the immune, interferon, and properdin systems [9, 136]. They are found as key portions of the exoskeletons of insects and arthropods and cell walls of plants and microbes and perform as reserve foodstuffs and important components of intercellular, mucous secretions, synovial and ocular fluids, and blood serum in many organisms. Food Applications compiles recent data on the food applications of marine polysaccharides from such various sources as fishery products, microorganisms, seaweeds, microalgae, and corals [137, 138]. One of the applications of this biopolymer relates to a method for protecting against diseases induced by Streptococcus pneumoniae infections, which comprises mucosal administration of a S. pneumoniae capsular polysaccharide to a patient in need. 

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