Polysaccharide Xanthan Gum Research Articles

Fabrication of bacterial derived natural polysaccharide-based copolymer network hydrogels for use in drug delivery applications

Researchers are currently exploring polysaccharide gums extensively to develop materials for biomedical applications. Herein, the bacterial-derived natural polysaccharide xanthan gum (XG) was utilized to develop copolymer network hydrogels to use in drug delivery (DD) applications for sustainable development. These copolymers were synthesized by grafting METAC onto XG and characterized by FE-SEM, EDX, AFM, FTIR, XRD, 13C NMR, DSC, and TGA-DTG techniques. These hydrogels were encapsulated with the anticancer drug dacarbazine. The diffusion of dacarbazine from the hydrogels exhibited a non-Fickian diffusion mechanism, and the release profile was most appropriately explained by a zero-order kinetic model. In addition, network hydrogels illustrated their superabsorbent nature by absorbing about 15 g of fluid per gram of polymer sample. The materials revealed antioxidant activity in the DPPH scavenging method. Findings of the physicochemical, drug delivery, antioxidant and antibacterial properties of copolymers revealed their suitability for use in DD applications.

Development of thiolated xanthan gum-stearylamine conjugate based mucoadhesive system for the delivery of biochanin-A to melanoma cells

Recently, instead of creating new active compounds, scientists have been working to increase the bioavailability and residence time of existing drugs by modifying the characteristics of the delivery systems. In the present study, a novel mucoadhesive bioconjugate (SN-XG-SH) was synthesized by functionalizing a polysaccharide xanthan gum (XG) with cysteamine hydrochloride (CYS) and a lipid stearylamine (SN). FTIR, CHNS and 1H NMR studies confirmed the successful synthesis of SN-XG-SH. Mucoadhesion of the thiolated XG was enhanced and evaluated by different methods. Disulfide bond formation between thiolated XG and skin mucus enhances mucoadhesive behavior. The mucoadhesive bioconjugate was used to prepare nanoparticles for the delivery of hydrophobic biochanin-A (Bio-A) for the treatment of melanoma. The thiolated xanthan gum nanoparticles also demonstrated high drug entrapment efficiency, sustained drug release, and high storage stability. The drug loaded nanoparticles (Bio-A@TXNPs) significantly improved the cytotoxicity of Bio-A against human epidermoid cancer cells (A431 cells) by inducing apoptosis and changing mitochondrial membrane potential. In conclusion, thiolation of XG improves its mucoadhesive properties and prolongs the release of Bio-A. Thus, thiolated XG conjugate has a high potential for use as a bioadhesive agent in controlled and localised delivery of drugs in different skin diseases including melanoma.

Vegetation growth promotion and overall strength improvement using biopolymers in vegetated soils

Planting vegetation is a sustainable and eco-friendly method for shallow slope stabilization. However, in water-limited regions, this method is facing challenges such as retarded vegetation growth, which leads to unprotected soils. Biopolymers, with potentials in both vegetation growth promotion and soil strength enhancement, are therefore tested in this study with regard to their possibility in assisting soil reinforcement with vegetation through vegetation cultivation and direct shear tests. Both sugar-based and protein-based biopolymers improved water availability to growing plants and nutrient uptake. The most suitable polysaccharide xanthan gum was adopted to further explore the effects of treatment conditions (i.e., blending content) and external environment (i.e., precipitation) on the vegetated soil performance. Under a variety of water supplies, xanthan gum with a medium blending content of 0.5% (i.e., with respect to dry soil mass) led to the most substantial improvement in the ability to resist shear loading. This indicates that the appropriate dosage of biopolymers used at the initial stage of plant growth should provide moderate bond strength between soil particles, while not impeding root penetration. Supported by the obtained results, biopolymers are suggested to be used in combination with plants for soil reinforcement for the best efficiency.

Thermal hysteresis phenomena in aqueous xanthan gum solutions

The anionic hydrocolloid polysaccharide xanthan gum is widely used in the food and petroleum industries (among others) as a viscosity enhancement polymer due to its high viscosity at low concentrations and moderate temperatures. The physical properties of microbial polysaccharide xanthan gum aqueous solutions were investigated using temperature dependent viscosity measurements. Specifically, the effect of thermal history on the solution viscosity was investigated. Heating and cooling cycles were assessed in two ways, by using a “sawtooth” and “triangle” pattern, which essentially differed in the rates of cooling. The sawtooth method used a cooling rate of 2.0 °C min−1 whereas the triangle pattern had a cooling rate of 0.20 °C min−1. The sawtooth cooling rate was controlled by the speed at which the Peltier device could cool the sample, and the triangle rate was governed by the time required to measure the viscosity at each temperature on return to the initial value. Cycles measured using the sawtooth pattern for 16 mg/kg xanthan gum in water showed an 8–10% overall decrease in the viscosity over four complete cycles. Comparatively, at 320 mg/kg the xanthan gum solution showed a 25% decrease in viscosity over four cycles. The observed temperature dependent viscosity variation suggested minor modifications in the physical network structure of xanthan gum. When using a triangle heating/cooling pattern, the overall decrease in the xanthan gum solution viscosity was 5–7% for 16 mg/kg and only 10% change for 320 mg/kg solutions. The activation energy of viscous flow for the aqueous xanthan gum solutions by either method was ∼15.0 kJ/mol under all conditions. The data showed that temperature and heating cycles influence xanthan gum viscosity and thermal history, which depends more strongly on xanthan gum concentration than solution temperature.

Asymmetric polysaccharide-bound graphene electrode configuration with enhanced electrosorption performance for uranium (VI) ions

As an energy-saving and facile technology, the potential of capacitive deionization (CDI) starts to surface in enrichment and recovery of uranium (U(VI)) from aqueous solutions. However, co-ion expulsion effect and poor surface wettability of electrode materials limit the eletrosorption performance. Here, polysaccharides xanthan gum (XG)- and chitosan (CS) -bound porous reduced graphene (RGH) electrodes were rationally designed, and then assembled into asymmetrical electrode configuration for U(VI) eletrosorption. Owing to the introduction of polysaccharide binders, the oppositely charged groups on the surface of cathode and anode weaken the co-ions exclusion effect as well as endow their superior surface hydrophilicity and electroconductivity, which facilitates the electrosorption for U(VI). Meanwhile, the negatively charged carboxylate groups could act as extra micro electric fields to attract U(VI) cations, and form stronge complexation between them. As a consequence, asymmetrical polysaccharide-bound RGH configuration gave rise to a larger removal ratio of 97.9% within 4 h at 1.2 V, as well as 2.5 times faster kinetics than symmetrical PVDF-bound RGH electrode configuration. Moreover, the accumulated adsorption capacity in six adsorption–desorption cycles of the former is up to 1413.0 mg g−1, 75% higher than the latter, which is of practical significance and economic benefit for electrosorption application.

Fabrication of Zinc Oxide-Xanthan Gum Nanocomposite via Green Route: Attenuation of Quorum Sensing Regulated Virulence Functions and Mitigation of Biofilm in Gram-Negative Bacterial Pathogens

The unabated abuse of antibiotics has created a selection pressure that has resulted in the development of antimicrobial resistance (AMR) among pathogenic bacteria. AMR has become a global health concern in recent times and is responsible for a high number of mortalities occurring across the globe. Owing to the slow development of antibiotics, new chemotherapeutic antimicrobials with a novel mode of action is required urgently. Therefore, in the current investigation, we green synthesized a nanocomposite comprising zinc oxide nanoparticles functionalized with extracellular polysaccharide xanthan gum (ZnO@XG). Synthesized nanomaterial was characterized by structurally and morphologically using UV-visible spectroscopy, XRD, FTIR, BET, SEM and TEM. Subinhibitory concentrations of ZnO@XG were used to determine quorum sensing inhibitory activity against Gram-negative pathogens, Chromobacterium violaceum, and Serratia marcescens. ZnO@XG reduced quorum sensing (QS) regulated virulence factors such as violacein (61%), chitinase (70%) in C. violaceum and prodigiosin (71%) and protease (72%) in S. marcescens at 128 µg/mL concentration. Significant (p ≤ 0.05) inhibition of biofilm formation as well as preformed mature biofilms was also recorded along with the impaired production of EPS, swarming motility and cell surface hydrophobicity in both the test pathogens. The findings of this study clearly highlight the potency of ZnO@XG against the QS controlled virulence factors of drug-resistant pathogens that may be developed as effective inhibitors of QS and biofilms to mitigate the threat of multidrug resistance (MDR). ZnO@XG may be used alone or in combination with antimicrobial drugs against MDR bacterial pathogens. Further, it can be utilized in the food industry to counter the menace of contamination and spoilage caused by the formation of biofilms.

Superabsorbent composites (SACs) based on xanthan gum-g-poly (itaconic acid)/kaolinite

In this present investigation, crosslinked polyitaconic acid (PIA) was grafted onto natural polysaccharides xanthan gum and inorganic clay kaolinite using free radical polymerization in an inert atmosphere using FTIR ammonium persulfate (APS) as an initiator and Tetra (ethylene glycol) diacrylate (TEGDA) as a crosslinking agent. Scanning electron microscopy and Fourier transform infrared spectra techniques were used to characterized for structure SAPs. The effect of various parameters which include APS, TEGDA, neutralizing degree, kaolinite contents, and xanthan gum was investigated. The results indicate that PIA successfully grafted onto xanthan gum and a 3D structure was formed. The results indicated with an increasing Xanthan gum/kaolin weight ratio, swelling capacity, and gel content.

Effect of Evaporation Rate on Meniscus Splitting with Formation of Vertical Polysaccharide Membranes

AbstractEvaporative self‐assembly of polymeric colloids is among the most attractive strategies for the preparation of soft materials with submicrometer‐scale ordered structures. In this study, meniscus splitting from an aqueous solution of liquid crystalline (LC) polysaccharide xanthan gum is verified under conditions of controlled evaporative rate in a limited space. Under fast evaporation rate with a steep gradient of humidity above the air–LC interface, the meniscus splitting is induced to bridge the gap and a vertical membrane with uniaxial orientation is obtained. The process is thermodynamically and polariscopically validated focusing on the ordered polymeric adsorption and the bridging of the millimeter‐scale gap. This clarification will serve not only as a method for immobilization of fluidically ordered structures but also in the control of the evaporative interface for the ordering of polymer solutions into advanced membranes with uniaxial orientation.

Depression mechanism of pyrophyllite by a novel polysaccharide xanthan gum

Pyrophyllite is the most common hydrophobic mineral encountered in Fengshan iron sulfide ore, China. Commonly depressants for separation of pyrophyllite suffer the disadvantages of limited availability and high cost. To solve this problem, a novel polysaccharide xanthan gum (XGM) was proposed for the suppression of pyrophyllite. The flotation response and depression mechanism were examined by flotation tests, adsorption and Fourier transform infrared spectra (FTIR), and molecular dynamics simulation (MDS) as well as scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The flotation and adsorption tests showed that the floatability of pyrophyllite became weaker after adding the polysaccharide XGM compared with the conventional depressant guar gum (GG) and carboxymethyl cellulose (CMC). Meanwhile, the greater adsorption amount of XGM on the pyrophyllite surface was obtained than that of GG and CMC. Fourier transform infrared spectra, scanning electron microscope and molecular dynamics simulation were conducted to reveal the depression mechanism. The XGM molecule preferred to pyrophyllite surface, and anionic XGM strongly absorbed on pyrophyllite (1 0 0), (0 1 0) surfaces by COO− groups in its molecular structure. After treating with XGM, the oxygen atom was enriched and sodium atom was found on the pyrophyllite surface, which caused a strong chemisorption between XGM and pyrophyllite. On the whole, the polysaccharide XGM is an excellent depressant for pyrophyllite suppression.

An updated method for the calibration of transparent exopolymer particle measurements

AbstractTransparent exopolymer particles (TEP) are biologically derived, polysaccharide‐rich, gel‐like particles that play important roles in ocean carbon cycling. The original spectrophotometric method for TEP quantification published in 1995 by Passow and Alldredge describes staining TEP with the dye Alcian Blue (AB), and calibration of the AB staining solution using a commercially available polysaccharide xanthan gum (XG) powder as the reference material. In the original method, a XG solution is prepared to create gel‐like particles that resemble TEP. The solution is filtered to collect the XG gels onto a filter, and the filters are stained with AB solution. However, recently, it has been found that the XG powder commercially available today has higher solubility and forms negligible amounts of gel particles in solution, which precludes its use as described in the original method. Here, we present an updated calibration method to generate reproducible XG calibration curves using the currently available XG powder, whereby a XG dilution series is stained with AB solution prior to filtration resulting in AB‐stained XG gels that are retained on a filter. Subsequent extraction and spectrophotometric analysis are performed as described in the original method. The updated calibration method described here yielded calibration curves consistent with those reported in the original method. The updated method should only be used in the preparation of a calibration curve when the new soluble XG is available, whereas samples for TEP quantification should be processed as described in the original method.

Xanthan gum-functionalised span nanoparticles for gene targeting to endothelial cells.

Endothelial cells play a critical role in many physiological processes; therefore, there is increasing evidence that the future of many treatments for pathologies depends on the development of endothelium-targeting systems. Thus, we have incorporated the natural polysaccharide xanthan gum (XG) into sorbitan monooleate nanoparticles to provide them with a hydrophilic and negatively charged surface shell with stabilising properties and an inherent ability to target endothelial cells. Enhanced Green Fluorescent Protein plasmid (pEGFP) was incorporated into the nanosystem, and the protection ability and stability of this system was confirmed. Nanoparticle cytotoxicity and transfection capacity were successfully tested in Human Umbilical Vein Endothelial Cells (HUVECs) before confirming their biocompatibility in vivo. Finally, biodistribution studies after pEGFP-XG nanoparticle systemic administration to mice evidenced GFP expression in the vascular endothelium of lung, liver and kidney, thus confirming the potential of xanthan gum-functionalised span nanoparticles for gene targeting to endothelial cells.

Biomimetic gels with chemical and physical interpenetrating networks

AbstractThis study aimed to create and to characterize the functional properties of gels with semi‐interpenetrating network (semi‐IPN) with focus on possible use of these composites in biomedical engineering. Polyacrylamide as a synthetic biocompatible polymer was chosen for the chemical network. The physical network comprised the gel‐forming polysaccharides xanthan gum or gellan gum. Gels were synthesized by radical polymerization of acrylamide in aqueous solutions of polysaccharides. Mechanical and electrical properties of gels with 0.2, 0.4, 0.6, 0.8 and 1.0 wt% content of polysaccharide were investigated. It was found that the inclusion of a small amount of xanthan or gellan into the polymeric network of a polyacrylamide gel significantly shifts the gel electrical potential towards the rest potential of living cells and Young's modulus towards the elasticity limits of biological soft tissues like non‐activated muscles. From the viewpoint of biomedical applications, the main advantage of the proposed composites is that the semi‐IPN structure provides a nonlinear dependence of gel tension on gel deformation, which mimics the elasticity of natural tissues. This feature opens the possibility for the promising use of the proposed gels for musculoskeletal minibioimplants or scaffolds for tissue engineering. © 2018 Society of Chemical Industry

Sugar Metabolism of the First Thermophilic Planctomycete Thermogutta terrifontis: Comparative Genomic and Transcriptomic Approaches.

Xanthan gum, a complex polysaccharide comprising glucose, mannose and glucuronic acid residues, is involved in numerous biotechnological applications in cosmetics, agriculture, pharmaceuticals, food and petroleum industries. Additionally, its oligosaccharides were shown to possess antimicrobial, antioxidant, and few other properties. Yet, despite its extensive usage, little is known about xanthan gum degradation pathways and mechanisms. Thermogutta terrifontis, isolated from a sample of microbial mat developed in a terrestrial hot spring of Kunashir island (Far-East of Russia), was described as the first thermophilic representative of the Planctomycetes phylum. It grows well on xanthan gum either at aerobic or anaerobic conditions. Genomic analysis unraveled the pathways of oligo- and polysaccharides utilization, as well as the mechanisms of aerobic and anaerobic respiration. The combination of genomic and transcriptomic approaches suggested a novel xanthan gum degradation pathway which involves novel glycosidase(s) of DUF1080 family, hydrolyzing xanthan gum backbone beta-glucosidic linkages and beta-mannosidases instead of xanthan lyases, catalyzing cleavage of terminal beta-mannosidic linkages. Surprisingly, the genes coding DUF1080 proteins were abundant in T. terrifontis and in many other Planctomycetes genomes, which, together with our observation that xanthan gum being a selective substrate for many planctomycetes, suggest crucial role of DUF1080 in xanthan gum degradation. Our findings shed light on the metabolism of the first thermophilic planctomycete, capable to degrade a number of polysaccharides, either aerobically or anaerobically, including the biotechnologically important bacterial polysaccharide xanthan gum.

Rheology and flow studies of drag-reducing gravel packing fluids

Viscoelastic additives are widely used as drag reducers in the oil and gas industry, and both polymeric additives and micellar surfactants are commonly used in well gravel packing applications. While the behaviour of polymeric additives such as the polysaccharide xanthan gum is well characterized in the literature, much less is known about how the rheology of the viscoelastic surfactants affects drag reduction, despite widespread use. In this study, we performed a number of rheological tests as well as flow loop experiments on solutions of a zwitterionic surfactant to understand the structural characteristics of the fluids in order to make better process predictions. Unlike xanthan, which displays typical viscoelastic liquid characteristics, zwitterionic surfactant-based fluids display elastic gel-like behaviour. The gel-like behaviour suggests long and relatively unbreakable chain lengths of the wormlike micelles in the viscoelastic surfactant solution at room temperature leading to gelation by entanglement. Also, a shear-thickening behaviour of viscoelastic surfactant samples at higher shear rates is observed, possibly as a result of shear-induced structures. Finally, we present a novel representation scheme to depict the flow loop results for drag in the laminar and turbulent regime, and relate this data to the rheological characterization.

Electrostatic self-assembly of polysaccharides into nanofibers

In this study, the anionic polysaccharide Xanthan gum (X) was mixed with positively charged Chitosan oligomers (ChO), and used as building blocks, to generate novel nanofibers by electrostatic self-assembly in aqueous conditions. Different concentrations, ionic strength and order of mixing of both components were tested and observed to affect the diameter, which ranged from 100 to 500nm, and morphology of the self-assembled nanofibers. The release of diclofenac, as model drug, from self-assembled xanthan-chitosan nanofibers was demonstrated, suggesting that these nanostructures can be used in applications within life sciences such as drug delivery.

Time-dependent rheological behavior of natural polysaccharide xanthan gum solutions in interrupted shear and step-incremental/reductional shear flow fields

The objective of the present study is to systematically elucidate the time-dependent rheological behavior of concentrated xanthan gum systems in complicated step-shear flow fields. Using a strain-controlled rheometer (ARES), step-shear flow behaviors of a concentrated xanthan gum model solution have been experimentally investigated in interrupted shear flow fields with a various combination of different shear rates, shearing times and rest times, and step-incremental and step-reductional shear flow fields with various shearing times. The main findings obtained from this study are summarized as follows. (i) In interrupted shear flow fields, the shear stress is sharply increased until reaching the maximum stress at an initial stage of shearing times, and then a stress decay towards a steady state is observed as the shearing time is increased in both start-up shear flow fields. The shear stress is suddenly decreased immediately after the imposed shear rate is stopped, and then slowly decayed during the period of a rest time. (ii) As an increase in rest time, the difference in the maximum stress values between the two start-up shear flow fields is decreased whereas the shearing time exerts a slight influence on this behavior. (iii) In step-incremental shear flow fields, after passing through the maximum stress, structural destruction causes a stress decay behavior towards a steady state as an increase in shearing time in each step shear flow region. The time needed to reach the maximum stress value is shortened as an increase in step-increased shear rate. (iv) In step-reductional shear flow fields, after passing through the minimum stress, structural recovery induces a stress growth behavior towards an equilibrium state as an increase in shearing time in each step shear flow region. The time needed to reach the minimum stress value is lengthened as a decrease in step-decreased shear rate.

Transient rheological behavior of natural polysaccharide xanthan gum solutions in start-up shear flow fields: An experimental study using a strain-controlled rheometer

The objective of the present study is to experimentally investigate the transient rheological behavior of concentrated xanthan gum solutions in start-up shear flow fields. Using a strain-controlled rheometer, a number of constant shear rates were suddenly imposed to aqueous xanthan gum solutions with different concentrations and the resultant shear stress responses were measured with time. The main findings obtained from this study can be summarized as follows: (1) For all shear rates imposed, however low it may be, the shear stress is rapidly increased with time (stress overshoot) upon inception of steady shear flow before passing through the maximum stress value and then gradually decreased with time (stress decay) until reaching a steady state flow. (2) As the imposed shear rate is increased, a more pronounced stress overshoot takes place and the maximum stress value becomes larger, whereas both times at which the maximum stress is observed and needed to reach a steady state flow are shortened. (3) The maximum shear stress is linearly increased with shear rate in a double logarithmic scale and becomes larger with increasing concentration at equal shear rates. In addition, the time at which the maximum stress occurs exhibits a linear relationship with the inverse of shear rate in a double logarithmic scale for all xanthan gum solutions, regardless of their concentrations. (4) The shear stress is sharply increased with an increase in strain until reaching the maximum stress at small range of deformations. The maximum stress is observed at similar strain values, irrespective of the imposed shear rates lower than 10 1/s. (5) The Bird-Leider model can be successfully used with regard to quantitatively predicting the transient behavior of concentrated xanthan gum solutions. However, this model has a fatal weakness in terms of describing a decrease in shear stress (stress decay).

Obtaining process of interpolymeric complexes from lactalbumin, xanthan gum and pectin

In this work, the optimization process of interpolymeric complexes formation between lactalbumin and the polysaccharides xanthan gum and pectin was studied in order to define the optimum conditions for the complexes formation. For the experimental design, response surface methodology (RSM) for three independent variables was used. The optimum conditions for the complexes formation between lactalbumin and xanthan gum were: pH 6.6, NaCl concentration of 0.6 mol/L and xanthan gum concentration 0.083% w/v. And for the complexes formed between pectin and lactalbumin the conditions were: pH 6.6, NaCl concentration of 0.25 mol/L and pectin concentration of 0.113% w/v. The best fitted model for the experimental data was that corresponding to the complex xanthan gum-lactalbumin, whose coefficient of determination (R²) was 0.97.

Enhanced oil recovery performance and viscosity characteristics of polysaccharide xanthan gum solution

This study compared the potential applications of xanthan gum and hydrolyzed polyacrylamide (HPAM) as polymer-flooding agents for heavy oil recovery applications under a range of salinity conditions. Rheological measurements were carried out to examine the change in shear viscosity when the polymer was applied under a range of reservoir conditions. The results showed that the shear viscosity of the xanthan gum solution was less sensitive to increasing temperatures and salinity than that of the HPAM solution. Accordingly, a xanthan gum injection is more effective than HPAM under higher salinity reservoir conditions.

Metabolic flux pattern of glucose utilization by Xanthomonas campestris pv. campestris: prevalent role of the Entner-Doudoroff pathway and minor fluxes through the pentose phosphate pathway and glycolysis.

The well-studied plant pathogenic bacterium Xanthomonas campestris pv. campestris (Xcc) synthesizes the biotechnologically important polysaccharide xanthan gum, which is also regarded as a virulence factor in plant interactions. In Xcc, sugars like glucose are utilized as a source to generate energy and biomass for growth and pathogenicity. In this study, we used [1-(13)C]glucose as a tracer to analyze the fluxes in the central metabolism of the bacterium growing in a minimal medium. (13)C-Metabolic flux analysis based on gas chromatography-mass spectrometry (GC-MS) confirmed the prevalent catabolic role of the Entner-Doudoroff pathway. Comparative nuclear magnetic resonance (NMR)-based isotopologue profiling of a mutant deficient in glycolysis gave evidence for a moderate flux via glycolysis in the wild-type. In addition to reconfirming the Entner-Doudoroff pathway as a catabolic main route, this approach affirmed a numerically minor but important flux via the pentose phosphate pathway.