Production and Rheological Properties of Welan Gum Produced by Sphingomonas sp. ATCC 31555 with Different Nitrogen Sources

2017 ◽  
Vol 27 (1) ◽  
pp. 55-63 ◽  
Author(s):  
Xiaopeng Xu ◽  
Zuoming Nie ◽  
Zhiyong Zheng ◽  
Li Zhu ◽  
Xiaobei Zhan
Keyword(s):  
Molecular Weight ◽  
Rheological Properties ◽  
Biomass Concentration ◽  
Bacterial Biomass ◽  
Nitrogen Sources ◽  
Monosaccharide Composition ◽  
Solution Concentration ◽  
Molar Ratio ◽  
Welan Gum ◽  
Beef Extract

This study aimed to investigate the effect of nitrogen sources on the production and rheological properties of welan gum produced by <i>Sphingomonas</i> sp. ATCC 31555. Six different nitrogen sources were used for ATCC 31555 fermentation, and 2 of these were further analyzed due to their more positive influence on welan gum production and bacterial biomass. Bacterial biomass, welan gum yield, welan viscosity, molecular weight, monosaccharide composition, acyl content, and welan structure were analyzed. Welan gum production and the biomass concentration of ATCC 31555 were higher in media containing NaNO<sub>3</sub> and beef extract. Welan viscosity decreased at higher temperatures of 30-90°C, and it increased with a higher welan concentration. In the media containing NaNO<sub>3</sub> (3 g·L<sup>-1</sup>), welan viscosity was higher at 30-70°C and a welan solution concentration of 6-10 g·L<sup>-1</sup>. With a reduced NaNO<sub>3</sub> concentration, the molecular weight of welan gum and the molar ratio of mannose decreased, but the molar ratio of glucuronic acid increased. With different nitrogen sources, the acetyl content of welan gum differed but its structure was similar. NaNO<sub>3</sub> and beef extract facilitated welan production. A reduced NaNO<sub>3</sub> concentration promoted welan viscosity.

scholarly journals Purification and Characterization of a New Lectin from Loach Skin Mucus

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Peng-peng Sun ◽  
Yuan-yuan Ren ◽  
Jie Zheng ◽  
Ai-jun Hu
Keyword(s):  
Molecular Weight ◽  
Carbohydrate Chain ◽  
Acid Resistance ◽  
Monosaccharide Composition ◽  
Molar Ratio ◽  
Pathogen Defense ◽  
Hemagglutination Activity ◽  
Purification And Characterization ◽  
Skin Mucus

Lectin from loach skin mucus plays an important role in pathogen defense. However, hardly can any paper relevant to the character of lectin from loach skin mucus be found in recent years. In this study, a kind of new lectin (LML), with a high hemagglutination activity of 166.23 × 103 HU/mg, was successfully isolated and purified from loach skin mucus. LML was a kind of glycoprotein with a molecular weight of 245 kDa. Also, the monosaccharide composition suggested that its carbohydrate chain was composed of rhamnose, arabinose, xylose, mannose, glucose, and galactose with a molar ratio of 2.02 : 11.66 : 2.06 : 1.00 : 14.09 : 6.00. Besides, LML depended on Ca2+ to induce hemagglutination and was strongly inhibited by D-lactose. The lectin exhibited powerful resistance to alkali and kept about 30% hemagglutination activity at pH 14.0, whereas its capacity of acid resistance was weak. The maximum hemagglutination activity of LML maintained at a temperature range from 20°C to 50°C. Moreover, the structure of LML was preliminarily studied, indicating it contained abundant glutamic acid, histidine, and serine, and its secondary structure contained α-helix (4.97%), β-sheet (27.55%), turns structure (49.78%), and unordered structure (17.70%).

Effect of different nitrogen sources on the viscosity and rheological properties of welan gum produced by Sphingomonas sp. ATCC 31555

2020 ◽  
Vol 51 (4) ◽  
pp. 642-649 ◽  
Author(s):  
Xiaopeng Xu ◽  
Zuoming Nie ◽  
Zhiyong Zheng ◽  
Li Zhu ◽  
Xiaobei Zhan
Keyword(s):  
Rheological Properties ◽  
Nitrogen Sources ◽  
Welan Gum

Study on Spinnability of UHMW/PAN Dope in DMSO

2014 ◽  
Vol 789 ◽  
pp. 255-258
Author(s):  
Wei Feng Du ◽  
Hui Fang Chen
Keyword(s):  
Molecular Weight ◽  
Strain Rate ◽  
Rheological Properties ◽  
Solution Concentration ◽  
Extensional Viscosity ◽  
Low Level ◽  
Additive Content ◽  
Ultrahigh Molecular Weight ◽  
Extensional Strain ◽  
Higher Temperature

The extensional rheological properties of the PAN/DMSO spinning solution using ultrahigh molecular weight (UHMW) PAN as additive were studied. The effects of the additive content on the extensional rheological curve, the extensional viscosity, as well as the spinnability of the PAN/DMSO spinning solution were investigated. The results revealed that the spinnability was related to such factors as solution concentration, additive content, temperature, apparent extensional viscosity and extensional strain rate. The effect of additive on the spinnability of the spinning solution turned out to be small when additive contents were set at a very low level. The spinnability of the spinning solution was optimized when the additive content was 0.5%wt, while the spinning solution adding 1%wt additive had a good spinnability only at a relatively higher temperature.

scholarly journals A Polysaccharide Produced by Lactococcus lactis subsp. lactis YZ1 Isolated from Traditional Indonesian Fermented Milk, "Dadih"

2000 ◽  
Vol 1 (1) ◽  
pp. 1-5
Author(s):  
Yusdar Zakaria
Keyword(s):  
Molecular Weight ◽  
Ion Exchange ◽  
Lactococcus Lactis ◽  
Monosaccharide Composition ◽  
Fermented Milk ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Molar Ratio ◽  
Neutral Sugar ◽  
Glycoside Linkage

ABSTRACT.Lactococcus lactis subsp. Lactis YZI was isolated from M17 agar in which diluted Dadih was poured and incubated at 30 0C for 48 h. Taxonomix properties of the isolate were examined according to Bergey’s Manual of Systematic Bacteriologi and Manual for  Identification of Medical Bacteria. The isolation of polysaccharide from the precipitant was performed on an ion-exchange chromatography. The result showed that the polysaccharides produced by Lactococus lactis subsp. lactis YZI were neutral sugar (unadsorbrd fraction) and glycoconjugated (absorbed fraction). The neutral sugar had molecular weight of 10,000 and 20,000 with and α-glycoside linkage. The monosaccharide composition was mannose, glucose and galactose with a molar ratio of 1 :1,5 : 4,9.

Hyperbranched unsaturated polyester amide synthesized by two-step method

2019 ◽  
Vol 48 (1) ◽  
pp. 29-35
Author(s):  
Hongjuan Zheng ◽  
Weiqiang Song
Keyword(s):  
Molecular Weight ◽  
Rheological Properties ◽  
Unsaturated Polyester ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Step Method ◽  
One Pot ◽  
Content Type ◽  
Hyperbranched Poly ◽  
Practical Implications

PurposeHyperbranched poly(ester-amide)s (HPEAs) have been synthesized from diethanolamine and maleic anhydride with ethylene glycol as a core monomer by using a two-step method, which are marked as Hupea polymers, and dehydration was carried out in xylene under reflux.Design/methodology/approachIn comparison with Hupea polymers was synthesized by one-pot method, Hupea polymers synthesized by two-step method has different structure and rheological properties. The intermediate monomer and the resulting polymer are characterized by FTIR and NMR spectroscopies.FindingsAll of Mw, Mn and Mw/Mn of the hyperbranch polymers decrease with the core/monomer molar ratio increasing. The intrinsic viscosity ([η]) of the polymers decreases with Mw increasing in the investigated range of Mw and scales as [η]∼Mw-0.82, which implies that the molecular weight grew faster with core/monomer molar ratio decreasing than the volume in the investigated range of core/monomer molar ratio.Research limitations/implicationsThe hydrodynamic radius was calculated by using Einstein’s equation and scales as Rh ∼ Mw0.061, and the lower exponent reveals the slow growth in the volume of Hupea molecule. In addition, the viscosity of Hupea polymer in concentrated aqueous solution is independent of shear rate and slightly dependent on molecular weight.Practical implicationsHyperbranched poly(ester-amide)s (HPEAs) were synthesized by using a two-step method, which had different structure and rheological properties.Originality/valueHupea polymers show different features from Hupea polymers in structure and rheological properties, which revealed that the synthesis process of HPEA has effect on its performance.

scholarly journals Homologous Over-Expression of Chain Length Determination Protein EpsC Increases the Molecular Weight of Exopolysaccharide in Streptococcus thermophilus 05-34

2021 ◽  
Vol 12 ◽  
Author(s):  
Zhengyuan Zhai ◽  
Shuxin Xie ◽  
Hongxing Zhang ◽  
Huaxi Yi ◽  
Yanling Hao
Keyword(s):  
Molecular Weight ◽  
Chain Length ◽  
High Performance ◽  
Gel Permeation Chromatography ◽  
Streptococcus Thermophilus ◽  
Monosaccharide Composition ◽  
Molar Ratio ◽  
Gas Chromatography Mass Spectrometry ◽  
Over Expression ◽  
Length Determination

In Streptococcus thermophilus, EpsC is a polysaccharide co-polymerase which is involved in determining the chain length of EPS synthesized by the Wzx/Wzy-dependent pathway. Our previous study found that there was a positive correlation between transcription level of epsC and molecular weight of EPS in S. thermophilus 05-34. To further investigate the effects of EpsC on EPS biosynthesis, this gene was over-expressed in S. thermophilus 05-34 in this study. Reverse transcription qPCR and Western blotting confirmed the successful transcription and translation of epsC in 05-34, respectively. The yield of EPS was not affected by the over-expression of EpsC. Gas chromatography-mass spectrometry (GC-MS) showed that the monosaccharide composition was still composed of galactose and glucose in a molar ratio of 1.0:0.8, whereas high performance gel permeation chromatography (HPGPC) indicated that the molecular weight of EPS was increased from 4.62 × 105 Da to 9.17 × 105 Da by the over-expression of EpsC. In addition, S. thermophilus 05epsC which could produce higher molecular weight EPS improved the viscoelasticity and water-holding capacity of yogurt, but significantly reduced the level of syneresis in yogurt. In summary, these results indicated that homologous over-expression of EpsC in S. thermophilus could increase the molecular weight of EPS and improve the microrheological or physical properties of yogurt.

scholarly journals Characterization and Antioxidant Activity of a Low-Molecular-Weight Xanthan Gum

Biomolecules ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 730 ◽  
Author(s):  
Hu ◽  
Wang ◽  
Yu ◽  
He ◽  
Qiao ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Hydroxyl Radicals ◽  
Xanthan Gum ◽  
Glucuronic Acid ◽  
Reducing Power ◽  
Monosaccharide Composition ◽  
Molar Ratio ◽  
Low Molecular Weight ◽  
Oxygen Species ◽  
Superoxide Anions

In the present work, a low-molecular-weight xanthan gum (LW-XG) was successfully obtained via biodegradation of commercial xanthan by the endophytic fungus Chaetomium globosum CGMCC 6882. The monosaccharide composition of LW-XG was glucose, mannose, and glucuronic acid in a molar ratio of 1.63:1.5:1.0. The molecular weight of LW-XG was 4.07 × 104 Da and much smaller than that of commercial xanthan (2.95 × 106 Da). Antioxidant assays showed that LW-XG had a good scavenging ability on DPPH radicals, superoxide anions, and hydroxyl radicals and good ferric reducing power. Moreover, LW-XG exhibited excellent protective effect on H2O2-injured Caco-2 cells. Results of this work suggested that LW-XG could be used in foods or pharmaceuticals to alleviate and resist the oxidative damage induced by the overproduction of reactive oxygen species.

Purification and Structure Study on Exopolysaccharides Produced by Lactobacillus paracasei KL1-Liu from Tibetan Kefir

2013 ◽  
Vol 781-784 ◽  
pp. 1513-1518 ◽  
Author(s):  
Hui Liu ◽  
Yuan Hong Xie ◽  
Tao Han ◽  
Hong Xing Zhang
Keyword(s):  
Molecular Weight ◽  
High Performance ◽  
Monosaccharide Composition ◽  
Gradient Elution ◽  
Structure Study ◽  
Lactobacillus Paracasei ◽  
Molar Ratio ◽  
Test Results ◽  
Sample Concentration ◽  
Multi Level

To investigate the pure conditions of exopolysaccharides produced by Lactobacillus paracasei KL1-Liu from Tibetan Kefir, and to analyse the structure, we used Multi-level single-factor test to purify EPS by Sepharose CL-6B. And the purity of EPS was detected by UV scan and high performance liquid chromatogram (HPLC). EPS molecular weight and monosaccharide composition were determined by HPLC. Results: Adoption phosphate buffer gradient elution 0.02-0.10 mol/L, the velocity 0.25 mL/min, the sample concentration 1.0 mg/mL, the sample capacity 1.0 mL. Under this purification conditions, components EPSa and EPSb were obtained. The purities of EPSa and EPSb were 82.82% and 91.74% respectively, which were 1.4 and 1.5 times of the pre-purification. Purity Test results showed that EPSa and EPSb polysaccharide were single components, basically no nucleic acid and protein in them. Structural analysis revealed that the molecular weight of EPSa and EPSb were 4.60×104 Da and 2.12×104 Da detected by HPLC. EPSa monosaccharide components were glucose and rhamnose, and the molar ratio was 1:0.68. EPSb were composed of glucose, xylose and rhamnose, and the molar ratio was 1:0.77:0.69.

scholarly journals Research of Inonotus obliquus Oligosaccharide in Prevention of Hyperlipidemia

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Dawei Wu ◽  
Yanrong Zhang ◽  
Dawei Wang ◽  
Tingting Liu ◽  
Shanshan Zhang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Protective Effect ◽  
Intestinal Flora ◽  
Deae Cellulose ◽  
Monosaccharide Composition ◽  
Hot Water ◽  
Molar Ratio ◽  
Inonotus Obliquus ◽  
Glycosidic Bonds ◽  
Liver And Kidney

In this study, hot water was used to extract Inonotus obliquus oligosaccharide. DEAE-cellulose and Sepharose G-200 were used to purify Inonotus obliquus oligosaccharide. Inonotus obliquus oligosaccharide IOP-2A was obtained. Its molecular weight Mw is about 1000 Da. The monosaccharide composition and molar ratio were glucose : xylose : galactose : mannose = 54.1 : 13.6 : 13.2 : 6.7. In addition, it also contains a small amount of galactose, gluconic acid, rhamnose, and fucose. IOP-2A contained mainly β-glycosidic bonds. Among them, 1,4-glycosidic bonds accounted for 9.2%, and 1,6-glycosidic bonds accounted for 85.1%. Oligosaccharide macromolecules formed a layered structure. Mouse experiments showed that IOP-2A had the function of preventing hyperlipidemia. At the same time, IOP-2A had a certain protective effect on the liver and kidney. The mechanism of IOP-2A in preventing hyperlipidemia was obtained from the perspective of mouse intestinal flora.

Culture conditions for the production of an acidic exopolysaccharide by the nitrogen-fixing bacterium Burkholderia tropica

2006 ◽  
Vol 52 (5) ◽  
pp. 489-493 ◽  
Author(s):  
Rodrigo V Serrato ◽  
Guilherme L Sassaki ◽  
Leonardo M Cruz ◽  
Fábio O Pedrosa ◽  
Philip A.J Gorin ◽  
...  
Keyword(s):  
High Performance ◽  
C:N Ratio ◽  
Great Influence ◽  
Nitrogen Sources ◽  
Monosaccharide Composition ◽  
Culture Conditions ◽  
Size Exclusion ◽  
Molar Ratio ◽  
Isolation And Purification ◽  
Synthetic Media

The endophytic diazotrophic bacterium Burkholderia tropica, strain Ppe8, produced copious amounts of exopolysaccharide (EPS) on batch growth in liquid synthetic media containing mannitol and glutamate as carbon and nitrogen sources. The effect of various aeration regimes and carbon source concentrations on EPS production was determined, as well as the effects of temperature and time of growth. The degree of aeration had a great influence on the yield of EPS, in contrast with the C:N ratio of the medium. Growth temperature also affected the EPS yield after the first 24 h of culture but seemed to be irrelevant after that. After isolation and purification, the EPS was analyzed by high-performance size exclusion chromatography and multiangle laser light scattering (HPSEC–MALLS), revealing a molecular mass of 300 kDa. The acid hydrolyzate of EPS was examined by HPLC and found to contain Glc, Rha, GlcA, and an aldobiouronic acid. The latter was found to have a GlcA and a Rha unit. Carboxy-reduced EPS contained Glc and Rha (3:2). The monosaccharide composition of the native acidic EPS was calculated as GlcA, Glc, and Rha in a molar ratio of 1:2:2.Key words: Burkholderia, endophyte, diazotrophic, exopolysaccharide, EPS.

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