Structure of the exopolysaccharide produced by Enterobacter amnigenus (original) (raw)
Related papers
Recent Trends in the Characterization of Microbial Exopolysaccharides
Oriental Journal of Chemistry, 2014
Bacterial polysaccharides that are secreted into the environment are termed as exopolysaccharides (EPSs). Depending on the monosaccharide composition, EPSs can be classified into homo (HoPSs) and heteropolysaccharides (HePSs). HoPSs consist of only one type of monosaccharide, mostly glucose or fructose. In the recent years, EPSs have drawn increasing attention of the researchers worldwide, not only for their thickening, texturizing and viscosifying properties, but also for their health promoting applications. These EPSs constitute an alternative class of biothickeners, which have also been proved to have good emulsifying property, apart from their texture promoting ability in various foods. The biochemical properties of the EPSs depend on the primary structure of the EPSs. Hence it is very important to know the monomeric composition of the EPSs and their gycosidic bonds. HPLC, GC, GC-MS, NMR, Capillary electrophoresis and various bioinformatics tools can be used to determine the chemical characteristics of the EPSs.
Fucose-containing exopolysaccharide produced by the newly isolated Enterobacter strain A47 DSM 23139
Carbohydrate Polymers, 2011
Enterobacter strain A47 (DSM 23139) was found to produce a fucose-containing exopolysaccharide (EPS). The EPS is composed of fucose, galactose, glucose, pyruvate, succinate and acetate in the molar ratios 1.6:1.3:1.1:1.2:0.7:1.5. It is a high molecular weight (5.8 × 10 6 ) homogeneous biopolymer, as indicated by the low polydispersity value (1.3). The steady shear flow properties of the EPS aqueous solutions are similar to guar gum and fucogel, and its viscoelastic properties indicate the formation of viscous aqueous solutions with entangled polymer chains. Additionally, the EPS has demonstrated good flocculating and emulsion stabilizing capacities, comparable to some commercially available products. These functional properties make the fucose-containing EPS a good alternative to many synthetic polymers, as well as other natural polysaccharides, in several applications in the food, pharmaceutical, cosmetic, textile, paper and petroleum industries.
Structure-function relationships in microbial exopolysaccharides
Biotechnology Advances, 1994
Sufficient well-characterized microbial exopolysaccharides arc now available to permit extensive studies on the relationship between their chemical structure and their physical attributes. This is seen even in homopolysaccharides with relatively simple structures but is more marked when greater differences in structure exist, as are found in several heteropolysaccharides. The specific and sometimes unique properties have, in the case of several of these polymers, provided a range of commercial applications. The existence of "families" of structurally related polysaccharides also indicates the specific role played by certain structures and substituents; the characteristics of several of these microbial polysaecharide families will be discussed here. Thus, microbial exopolysaccharides frequently carry acyl groups which may profoundly affect their interactive properties although these groups often have relatively little effect on solution viscosity. Xanthan with or without acylation shows marked differences in synergistic gelling with plant giuco-and galacto-mannans, although the polysaccharides with different aeylation patterns show similar viscosity. Similarly "gelrite" from the bacterium originally designated as Auromonas (Pseudomonas) elodea is of greater potential value after deacetylation, when it provides a valuable gelling agent, than it is as a viscosifier in the natural acylated form. The Klebsiella type 54 polysaccharide only forms gels when it, too, has been chemically deacetylated to give a structure equivalent to the Enterobacter XM6 polymer. Both these polysaccharides form gels due to the enhanced interaction with cations following deacylation and to the conformation adopted after removal of the acyl groups. Recent work in our laboratory suggests that deacetylation of certain bacterial alginates also significantly increases ion binding by these polysaccharides, making them more similar in their properties to algal alginates even although the alginates from some t'seudomonas species lack poly-L-gnluronic acid sequences. The existence within families of polysaccharides of types in which monosaceharides are altered within a specific structure, or with varying side-chains, also gives an indication of the way in which such substituents affect the physical properties of the polymers in aqueous solution.
Structural determination and NMR characterization of a bacterial exopolysaccharide
International Journal of Biological Macromolecules, 2013
A strain of Bacillus licheniformis with high exopolysaccharide (EPS) production ability was isolated and identified. A new type of EPS was isolated from the strain fermentation and its structural characteristics were investigated and elucidated by partial and total acid hydrolysis, Fourier transform infrared, and 1 H and 13 C NMR spectroscopy including 2D 1 H, COSY, NOESY, XHCOR and HMBC experiments. Based on obtained data, the EPS was found to be a levan composed of linear chains of (2 → 6)-linked -dfructofuranosyl residues with connections  (2 → 6).
Biochemical Journal, 2002
Centre de recherche et de de! veloppement sur les aliments, Agriculture et Agroalimentaire Canada, 3600 boulevard Casavant Ouest, Saint-Hyacinthe, Que! bec, Canada J2S 8E3 Exopolysaccharides (EPSs) were isolated and purified from Lactobacillus rhamnosus strains RW-9595M, which has been shown to possess cytokine-stimulating activity, and R grown under various fermentation conditions (carbon source, incubation temperature and duration). Identical "H NMR spectra were obtained in all cases. Molecular masses were determined by gel permeation chromatography. The primary structure was elucidated using chemical and spectroscopic techniques. Organic acid, monosaccharide and absolute configuration analyses gave the following composition : pyruvate, 1 ; -glucose, 2 ; -galactose, 1 ; and -rhamnose, 4. Methylation analysis indicated the presence of three residues of 3-linked rhamnose, and one residue each of 2,3-linked rhamnose, 2-linked glucose, 3-linked glucose and 4,6-linked galactose. The EPS was submitted to periodate oxidation followed by borohydride reduction. Monosaccharide
Bacterial Exopolysaccharides: Functionality and Prospects
International Journal of Molecular Sciences, 2012
Diverse structural, functional and valuable polysaccharides are synthesized by bacteria of all taxa and secreted into the external environment. These polysaccharides are referred to as exopolysaccharides and they may either be homopolymeric or heteropolymeric in composition and of diverse high molecular weights (10 to 1000 kDa). The material properties of exopolysaccharides have revolutionized the industrial and medical sectors due to their retinue of functional applications and prospects. These applications have been extensive in areas such as pharmacological, nutraceutical, functional food, cosmeceutical, herbicides and insecticides among others, while prospects includes uses as anticoagulant, antithrombotic, immunomodulation, anticancer and as bioflocculants. Due to the extensive applications of bacterial exopolysaccharides, this overview provides basic information on their physiologic and morphologic functions as well as their applications and prospects in the medical and industrial sectors.
Hue University Journal of Science: Natural Science
Strain Lactobacillus fermentum MC3 isolated from fermented bamboo shoots was used in this study. This isolate had a high exopolysaccharide (EPS) production capability. It was inoculated in the medium with a supplement of various concentrations of carbohydrate source (2, 3, 4, 5, and 6% (w/v)). The mixtures were then cultured under different conditions of initial cell density, temperatures, pH, and incubation time to identify the optimum parameters for the EPS biosynthesis of this strain. The EPS yield was measured using the phenolsulfuric acid method. The results showed that adding glucose, lactose, and sucrose to the culture medium significantly increased the EPS production with a maximum amount of 4% of sugars. The yield was the highest for glucose at 178.207 mg/L, and the obtained figures for lactose and sucrose were 148.614 mg/L and 152.272 mg/L, respectively. The results indicated that the EPS production by L. fermentum MC3 reached the maximum values at 200.728 mg/L in the medium supplemented with 4% glucose at 40 °C, pH 6.0, and initial cell density of 10 6 CFU/mL for 48 h cultivation. By methylation and gas-chromatography mass spectrometry (GC-MS), it was found that the exopolysaccharide is composed of D-mannose, D-glucose, and D-galactose at the molar ratio of 1:0.74:0.09.
Anais da Academia Brasileira de Ciências, 2012
The genus Leuconostoc belongs to a group of lactic acid bacteria usually isolated from fermented vegetables, which includes species involved in the production of exopolysaccharides (EPS). These biopolymers possess considerable commercial potential. Because of the wide variety of industrial applications of EPS, this study aimed to produce and characterize the native exopolysaccharide strain Leuconostoc pseudomesenteroides R2, which was isolated from cabbage collected in a semi-arid region of Bahia. We employed the following conditions for the production of EPS: 10.7% sucrose, pH 8.2, without agitation and incubation at 28ºC for 30 hours. The fermentation broth was treated with ethanol and generated two types of polysaccharide substances (EPS I and EPS II). The identification of EPS I and EPS II was conducted using FT-IR, ¹H, 13C and DEPT-135 NMR spectra. The two substances were identified as linear dextran α polysaccharides (1 → 6) which indicated different characteristics with respe...