The bacterial strain HDE-9 was isolated from sauerkraut and identified as Levilactobacillus brevis. An exopolysaccharide (EPS) was isolated and purified from L. brevis HDE-9, and a preliminary investigation of its structural characteristics and biological activity was conducted. The molecular weight of the EPS was >1.0 × 106 Da. Fourier transform infrared (FT-IR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy revealed that the EPS was composed of α-(1→6) linked D-glucopyranose units. X-ray diffraction (XRD) data on the EPS revealed its non-crystalline amorphous structure. Scanning electron microscopy (SEM) of the EPS revealed a smooth surface with sheet structures. The EPS exhibited the high value in thermal stability, water solubility, water holding capacity (WHC), and emulsification activity (EA). The water contact angle of the EPS revealed relatively high hydrophobicity in the presence of sucrose. The EPS also showed a strong milk solidification capacity in a dose-dependent manner. The EPS could significantly improve the texture of yoghurt, indicating its potential application as a functional starter in the production of fermented dairy products.

structure, exopolysaccharide, yoghurt, characteristics, Levilactobacillus brevis

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
	aDGlcp	97.75	71.36	73.34	69.54	69.54	65.61


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
	aDGlcp	4.90	3.58	3.75	3.89	3.89	3.73-3.98


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
	aDGlcp	97.75/4.90	71.36/3.58	73.34/3.75	69.54/3.89	69.54/3.89	65.61/3.73-3.98

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)

Fructan based biopolymers have been extensively characterized and explored for their potential applications. Linear chained biopolymers, like levan-type fructan, have gained attention because they have exhibited unconventional stretchable and unbendable properties along with biodegradable and biocompatible nature. Current study deals with the chemical characterization and cytotoxic analysis of fructose based exopolysaccharide that was extracellularly produced by an indigenously isolated bacterial species (Zymomonas mobilis KIBGE-IB14). Maximum yield of exopolysaccharide (44.7 gL-1) was attained after 72 h of incubation at 30 °C under shaking conditions (180 rpm) when the culture medium was supplemented with 150.0 gL-1 of sucrose as a sole carbon source. This exopolysaccharide displayed high water solubility index (96.0%) with low water holding capacity (17.0%) and an intrinsic viscosity of about 0.447 dL g-1. This biopolymer exhibited a characteristic linear homopolysaccharide structure of levan when characterized using Fourier Transform Infrared (FTIR), Nuclear Magnetic Resonance (NMR) spectroscopy (1H, 13C, TOCSY and NOESY) while, Atomic Force Microscopy (AFM) revealed its pointed and thorny structure. The decomposition temperature of levan was approximately 245 °C as revealed by Thermal Gravimetric Analysis (TGA). X-Ray Diffraction (XRD) results revealed its amorphous nature with crystalline phase. Cytotoxicity of different concentrations of levan was investigated against mouse fibroblast cell lines by measuring their cellular metabolic activity and it was noticed that a higher concentration of levan (2.0 mg ml-1) permitted the normal cell growth of NIH/3T3 cell lines. This non-cytotoxic and biocompatible nature suggests that this levan has the capability to be utilized in food and drug-based formulations as it exhibited biomedical potential.

exopolysaccharide, cytotoxicity, levan, chemical characterization, NIH/3T3 cell line

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
	bDFruf	62.59	106.9	78.98	77.89	82.99	65.32


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
	bDFruf	3.61-3.70	-	4.10	4.03	3.93	3.48-3.82


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
	bDFruf	62.59/3.61-3.70		78.98/4.10	77.89/4.03	82.99/3.93	65.32/3.48-3.82

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)

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)

A novel exopolysaccharide, designated hsEPS, was successfully prepared from the high-salt-fermented broth of a novel species Halomonas saliphila LCB169T by ethanol precipitation, anion-exchange and gel-filtration chromatography, and its structure was well-characterized by means of chemical and spectral analyses. Results showed that hsEPS was primarily composed of mannose and glucose with a relative weight-average molecular weight of 5.133 × 104 g/mol. It was deduced that the major backbone contained (1→2)-linked α-D-Manp and (1→6)-linked α-D-Manp with branches substituted at C-2 by T-α-D-Manp and at C-6 by the fragment of T-α-D-Manp-(1→2)-α-D-Manp-(1→. A sheet-like structure was observed under high magnification. The water solubility index, water holding capacity, oil holding capacity and foaming capacity of hsEPS were 98.0, 19.3, 1386.7 and 82.2%, respectively. It also exhibited outstanding emulsifying activity against all tested edible oils. Together, the resulted data indicated that hsEPS might serve as an active ingredient in food, cosmetics and detergents.

structure, exopolysaccharide, halophiles, Functional properties, Halomonas saliphila

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
2,6,2,6,2,2	aDManp	102.06	79.94	71.52	67.88	74.70	62.61
2,6,2,6,2,6	aDManp	103.69	71.58	71.87	68.41	74.82	62.52
2,6,2,6,2	aDManp	99.73	80.21	71.73	68.36	74.89	68.44
2,6,2,6	aDManp	102.06	79.94	71.52	67.88	74.70	62.61
2,6,2,2,2	aDManp	103.69	71.58	71.87	68.41	74.82	62.52
2,6,2,2	aDManp	102.06	79.94	71.52	67.88	74.70	62.61
2,6,2	aDManp	99.73	80.21	71.73	68.36	74.89	68.44
2,6,6,6	SUG
2,6,6	bDGlcp	104.52	74.58	77.11	69.65	74.42	67.71
2,6	aDManp	99.73	80.21	71.73	68.36	74.89	68.44
2	aDManp	103.60	71.14	70.36	67.94	74.68	68.6
	aDManp


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
2,6,2,6,2,2	aDManp	5.33	4.16	4.07	3.79	3.93	3.68-3.80
2,6,2,6,2,6	aDManp	5.18	4.11	3.92	3.69	3.83	3.70-3.95
2,6,2,6,2	aDManp	5.13	4.06	3.81	3.70	3.84	3.73-3.91
2,6,2,6	aDManp	5.33	4.16	4.07	3.79	3.93	3.68-3.80
2,6,2,2,2	aDManp	5.09	4.11	3.92	3.69	3.83	3.70-3.95
2,6,2,2	aDManp	5.33	4.16	4.07	3.79	3.93	3.68-3.80
2,6,2	aDManp	5.13	4.06	3.81	3.70	3.84	3.73-3.91
2,6,6,6	SUG
2,6,6	bDGlcp	4.56	3.37	3.53	3.68	3.79	3.61-3.99
2,6	aDManp	5.16	4.08	3.81	3.70	3.84	3.73-3.91
2	aDManp	5.08	4.26	3.90	3.78	3.96	3.76-3.83
	aDManp


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
2,6,2,6,2,2	aDManp	102.06/5.33	79.94/4.16	71.52/4.07	67.88/3.79	74.70/3.93	62.61/3.68-3.80
2,6,2,6,2,6	aDManp	103.69/5.18	71.58/4.11	71.87/3.92	68.41/3.69	74.82/3.83	62.52/3.70-3.95
2,6,2,6,2	aDManp	99.73/5.13	80.21/4.06	71.73/3.81	68.36/3.70	74.89/3.84	68.44/3.73-3.91
2,6,2,6	aDManp	102.06/5.33	79.94/4.16	71.52/4.07	67.88/3.79	74.70/3.93	62.61/3.68-3.80
2,6,2,2,2	aDManp	103.69/5.09	71.58/4.11	71.87/3.92	68.41/3.69	74.82/3.83	62.52/3.70-3.95
2,6,2,2	aDManp	102.06/5.33	79.94/4.16	71.52/4.07	67.88/3.79	74.70/3.93	62.61/3.68-3.80
2,6,2	aDManp	99.73/5.13	80.21/4.06	71.73/3.81	68.36/3.70	74.89/3.84	68.44/3.73-3.91
2,6,6,6	SUG
2,6,6	bDGlcp	104.52/4.56	74.58/3.37	77.11/3.53	69.65/3.68	74.42/3.79	67.71/3.61-3.99
2,6	aDManp	99.73/5.16	80.21/4.08	71.73/3.81	68.36/3.70	74.89/3.84	68.44/3.73-3.91
2	aDManp	103.60/5.08	71.14/4.26	70.36/3.90	67.94/3.78	74.68/3.96	68.6/3.76-3.83
	aDManp

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
[*]O[C@H]1[C@@H](O)[C@H](O)[C@@H](CO)O[C@@H]1O[C@H]1[C@@H](O)[C@H](O)[C@@H](CO[C@H]2O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]2O)O[C@@H]1O[C@@H]1[C@@H](OC[C@H]2O[C@H](O[C@H]3[C@@H](O)[C@H](O)[C@@H](CO)O[C@@H]3O[C@H]3[C@@H](O)[C@H](O)[C@@H](CO[C@H]4O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]4O)O[C@@H]3O[C@@H]3[C@@H](OC[C@H]4O[C@H](O[C@H]5[C@@H](O)[C@H](O)[C@@H](CO)O[C@@H]5O[C@H]5[C@@H](O)[C@H](O)[C@@H](CO[C@H]6O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]6O)O[C@@H]5O[C@@H]5[C@@H](OC[C@H]6O[C@H](O[C@@H]7[C@@H](OC[C@H]8O[C@H](O[C@H]9[C@@H](O)[C@H](O)[C@@H](CO)O[C@@H]9[*])[C@@H](O)[C@@H](O)[C@@H]8O)O[C@H](CO[C@@H]8O[C@H](CO[1*])[C@@H](O)[C@H](O)[C@H]8O)[C@@H](O)[C@@H]7O)[C@@H](O[C@H]7O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]7O[C@H]7O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]7O)[C@@H](O)[C@@H]6O)O[C@H](CO)[C@@H](O)[C@@H]5O)[C@@H](O[C@H]5O[C@H](CO)[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]4O)O[C@H](CO)[C@@H](O)[C@@H]3O)[C@@H](O[C@H]3O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]3O[C@H]3O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]3O)[C@@H](O)[C@@H]2O)O[C@H](CO)[C@@H](O)[C@@H]1O

4052.517 g/mol (C₁₅₀H₂₄₉R₃O₁₂₅, R = next and previous repeats / residue superclass(es), not counted in mol weight)