An exopolysaccharide (EPS) was produced by Leuconostoc pseudomesenteroides DRP-5 isolated from homemade wine. The EPS was obtained with ethanol extraction, which was further purified by chromatography of Sephadex G-100 to get a purified fraction. The monosaccharide composition of the EPS was glucose, and its molecular weight (Mw) was 6.23x10(6) Da, as determined by gas chromatography (GC) and high-performance size-exclusion chromatography (HPSEC). Fourier transform infrared spectra (FT-IR) and nuclear magnetic resonance spectra (NMR) showed that the EPS was a linear glucan with α-(1→6)-linked glucosidic bonds. The water holding capacity (WHC), water solubility index (WSI) and emulsifying activity (EA) of DRP-5 EPS were 296.76+/-18.93%, 98.62+/-3.57% and 87.22+/-2.18%, respectively. DRP-5 EPS have a higher degradation temperature of 278.36 degrees C, suggesting high thermal stability of the EPS. Also, DRP-5 EPS was found to have moderate 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical, superoxide anion radical, 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radical, Fe(2+) scavenging activities and reducing power. All these characteristics suggest that DRP-5 EPS might have potential applications in the pharmaceutical, cosmetic and food industries.

characterization, structural analysis, purification, Antioxidant activity, Leuconostoc pseudomesenteroides dextran

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]OC[C@H]1O[C@H]([*])[C@H](O)[C@@H](O)[C@@H]1O

162.141 g/mol (C₆H₁₀R₂O₅, R = next and previous repeats, not counted in mol weight)

A novel exopolysaccharide (named mhEPS) with a molecular weight of 5.881 × 104 g/mol was isolated from Gracilibacillus sp. SCU50's high-salt fermentation broth by ethanol precipitation, anion-exchange and gel-filtration chromatography before being structurally characterized and functionally evaluated. mhEPS consists of mannose, galactose, glucose and fucose in a molar ratio of 90.81:5.76:2.22:1.21. The backbone of mhEPS was (1→3,6)-linked α-D-mannopyranose residues, branched by single α-D-mannopyranose units attached to the main chain at C-2 position of every residue. The water solubility index, water holding capacity and oil holding capacity of mhEPS were 93.53, 14.89 and 1023.34%, respectively. mhEPS showed to possess good emulsifying activity against all tested substrates, and it could potentially increase the high-salinity tolerance of strain SCU50. The lack of toxicity of mhEPS was also preliminarily determined. Due to the functional properties of mhEPS, it is a good candidate to develop as an active ingredient in food, cosmetics and detergents.

exopolysaccharide, Structural characterization, functional evaluation, Gracilibacillus sp.

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
6,6,6,2	aDManp	103.97	71.60	71.74	67.93	74.82	62.52
6,6,6	aDManp	102.06	79.93	71.89	67.5	68.21	68.43
3,6	SUG
3	aDManp	103.69	71.14	71.52	67.47	67.87	68.23
6,2,6	SUG
6,2	aDManp	103.69	71.74	71.52	67.47	67.87	68.23
6,6,6,6	aDManp
6,6,3	aDManp	103.97	71.60	71.74	67.93	74.82	62.52
6,6	aDManp	99.74	71.22	79.40	67.33	?	?
6	aDManp	102.06	79.93	71.89	67.5	68.21	68.43
	aDManp	99.74	71.22	79.40	67.33	?	?


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
6,6,6,2	aDManp	5.20	4.11	3.88	3.80	3.78	3.77-3.79
6,6,6	aDManp	5.34	4.16	3.94	3.81	3.70	3.68-3.72
3,6	SUG
3	aDManp	5.08	4.26	3.99	3.84	3.73	3.75
6,2,6	SUG
6,2	aDManp	5.17	4.26	3.99	3.84	3.73	3.75
6,6,6,6	aDManp
6,6,3	aDManp	5.10	4.10	3.96	3.80	3.78	3.77-3.79
6,6	aDManp	5.14	4.07	4.00	3.82	?	?
6	aDManp	5.34	4.16	3.94	3.81	3.70	3.68-3.72
	aDManp	5.14	4.07	4.00	3.82	?	?


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
6,6,6,2	aDManp	103.97/5.20	71.60/4.11	71.74/3.88	67.93/3.80	74.82/3.78	62.52/3.77-3.79
6,6,6	aDManp	102.06/5.34	79.93/4.16	71.89/3.94	67.5/3.81	68.21/3.70	68.43/3.68-3.72
3,6	SUG
3	aDManp	103.69/5.08	71.14/4.26	71.52/3.99	67.47/3.84	67.87/3.73	68.23/3.75
6,2,6	SUG
6,2	aDManp	103.69/5.17	71.74/4.26	71.52/3.99	67.47/3.84	67.87/3.73	68.23/3.75
6,6,6,6	aDManp
6,6,3	aDManp	103.97/5.10	71.60/4.10	71.74/3.96	67.93/3.80	74.82/3.78	62.52/3.77-3.79
6,6	aDManp	99.74/5.14	71.22/4.07	79.40/4.00	67.33/3.82	?/?	?/?
6	aDManp	102.06/5.34	79.93/4.16	71.89/3.94	67.5/3.81	68.21/3.70	68.43/3.68-3.72
	aDManp	99.74/5.14	71.22/4.07	79.40/4.00	67.33/3.82	?/?	?/?

The spectrum also has 4 signals at unknown positions (not plotted).

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

R1 = SUG
Warning = sub-repeat ending at aDManp: unknown unit count was assumed to be 3
[1*]OC[C@H]1O[C@H](O[C@@H]2[C@@H](OC[C@H]3O[C@H](O)[C@@H](O)[C@@H](O[C@H]4O[C@H](CO[1*])[C@@H](O)[C@H](O)[C@@H]4O)[C@@H]3O)O[C@H](CO[C@H]3O[C@H](CO[C@H]4O[C@H](CO[C@H]5O[C@H](CO[C@H]6O[C@H](CO[C@H]7O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]7O)[C@@H](O)[C@H](O)[C@@H]6O[C@H]6O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]6O)[C@@H](O)[C@H](O)[C@@H]5O[C@H]5O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]5O)[C@@H](O)[C@H](O)[C@@H]4O[C@H]4O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]4O)[C@@H](O)[C@H](O[C@H]4O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]4O)[C@@H]3O)[C@@H](O)[C@@H]2O)[C@@H](O)[C@@H](O)[C@@H]1O

2123.832 g/mol (C₇₈H₁₃₀R₂O₆₆, R = residue superclass(es), not counted in mol weight)

Paenibacillus polymyxa 92, isolated from wheat roots, produced large amounts (38.4 g L-1) of exopolysaccharide (EPS) in a liquid nutrient medium containing 10 % (w/v) sucrose. The EPS was precipitated from the culture broth with cold acetone and was purified by gel filtration and anion-exchange chromatography. The molecular mass of the EPS was 2.29-1.10 × 105 Da. Diffuse reflectance infrared Fourier transform and nuclear magnetic resonance spectra showed that the EPS was a linear β-(2→6)-linked fructan (levan). Aqueous EPS solutions showed pseudoplastic behavior when shear stress was applied at different temperatures. By using the Ostwald-de Waele model, the rheological characteristics of the EPS solution were ascertained. The sorption capacity of the EPS for Zn(II), Cd(II), Pb(II), and Cu(II) was investigated. Sorption was maximal (q = 481 mg g-1) for Cu(II) ions. In model experiments, treatment of wheat seeds with EPS solution significantly increased the length of seedling roots and shoots.

exopolysaccharide, Rheology, levan, Paenibacillus polymyxa, Plant-growth-promoting activity

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
	bDFruf	61.7	105.3	78.0	76.7	81.4	64.6


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
	bDFruf	3.70-3.77	-	4.19	4.09	3.95	3.60-3.90


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
	bDFruf	61.7/3.70-3.77		78.0/4.19	76.7/4.09	81.4/3.95	64.6/3.60-3.90

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]OC[C@H]1O[C@]([*])(CO)[C@@H](O)[C@@H]1O

162.141 g/mol (C₆H₁₀R₂O₅, R = next and previous repeats, not counted in mol weight)