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Objective: The study aimed to identify a film sensitive to microbial decomposition to select an appropriate coating for delivering drugs to the colon. Methods & Materials: Different polysaccharides, including xanthan, inulin, carrageenan, and alginate, were made with Eudragit FS 30 D (EFS) by film formation method. The films were screened by performing mechanical tests, swelling percentage, the reduction of dry film mass, the passage of water vapor through (WVT) of the films, and the permeability of the films to the drug in different media similar to the gastrointestinal tract (GIT). Additionally, the films' characteristics were evaluated based on shape (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and differential scanning calorimetry (DSC). Results: The film evaluation results revealed that the inulin film had the highest work of failure (WF), % of elongation at break (%E), Tensile strength (TS), and elastic modulus (EM). Also, this film exhibited the highest TS/EM ratio. In contrast, other polysaccharide films exhibited the opposite behavior. The results of the dry film swelling and mass reduction tests in media with 1.2, 6.5, and 6.8 pH, as well as in the SCF medium, showed that in an acidic medium, films containing inulin and alginate have very low swelling and less degraded. In contrast, film containing xanthan showed very high swelling and high dry mass at different pHs. However, the alginate film showed lower swelling and dry mass than the xanthan film at all investigated pHs. The results of evaluating the WVT of the films showed that the highest and lowest WVT related to the films prepared from inulin and alginate, respectively. In addition, the highest ratio of the swelling index in the SCF medium compared to the buffered phosphate medium with pH 6.8 was observed in the film containing inulin. The results of the evaluation of the permeability of the films to the drug in different media similar to the GIT showed that the permeability of the inulin film to the drug in a gastric medium is very low. In contrast, the permeability of this film in the SCF medium significantly increased compared to the buffered medium with pH 6.8. The SEM studies showed that films containing xanthan and carrageenan degraded more than other polysaccharide films at pH 1.2. The evaluation and comparison of films in SCF-containing and non-SCF media showed that the degradation of films in SCF media was more significant. Evaluation of DSC and FTIR showed that the formed film containing EFS polymer lack of interaction with other polysaccharides. Conclusion: This study showed that inulin film is a suitable polysaccharide for colonic drug delivery systems due to its suitable mechanical properties, low swelling compared to the liquids of the upper parts of the GIT, and sensitivity to the enzymes in the colon. In other words, film coatings consisting of pH-dependent polymers such as EFS in combination with inulin can deliver drugs targeted to the end parts of the GIT. [ABSTRACT FROM AUTHOR]

This study aims to develop efficient adsorptive materials for retaining used 5w40 motor oil using xanthan (XG), xanthan esterified with acrylic acid (XGAC), Lignoboost lignin (LB), and LB esterified with oleic and stearic acids. The adsorption capacities of these materials were systematically evaluated, revealing a hierarchical efficacy with XG exhibiting the highest performance (60.16 g/g), followed by XGAC/LB (59.92 g/g) and XGAC (55.79 g/g). These capacities were correlated with the materials' surface area and morphology. Additionally, accelerated weathering studies assessed the degradation process of the adsorptive materials over time, revealing that all of them undergo significant structural changes, which suggests potential pathways for environmentally friendly disposal. Kinetic studies indicated that the experimental data fit well with the pseudo‐second‐order (PSO) model. The high correlation coefficient values for the PSO model (0.9318–0.9998) confirmed its suitability for describing the kinetics of oil sorption. FTIR spectra of the used motor oil‐loaded materials confirmed the physical nature of the adsorption process, involving interactions such as hydrogen bonding, van der Waals forces, and π–π interactions. SEM analysis demonstrated that materials with larger pore sizes showed less efficient oil adsorption despite having high porosity, highlighting the importance of optimal pore size distribution for effective adsorption. [ABSTRACT FROM AUTHOR]

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The sapodilla fruit has a limited shelf life due to its perishability and rapid moisture loss. The application of edible coatings has attracted much interest because they are effective in prolonging the shelf life of fruits. This study aims to evaluate the effectiveness of an edible coating made from xanthan gum (XG) (0.1% and 0.2%) combined with oleic acid (Ol) (1%) in prolonging the shelf life of sapodilla fruit at 8 ± 1 οc and a relative humidity (RH) of 85-90%. Weight loss was significantly reduced in the treated fruits, with the minimum weight loss observed in the Xan 0.2% + Ol treatment. Except for the Ol treatment, the other treatments showed a higher level of firmness compared to the control. At the end of the experiment, the treatments significantly reduced fruit respiration. The treated fruits also showed significantly increased antioxidant capacity and higher levels of ascorbic acid compared to the control. The lowest TSS (22.8%) level was noted in the Xan 0.2 + Ol treatment. Moreover, the results showed that fruit treated with Xan 0.1% + Ol coating exhibited higher activity in the superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) enzymes compared to the fruit treated with Xan 0.2 + Ol coating and the control samples. In general, fruits treated with Xan 0.2 + Ol and Xan 0.1% + Ol demonstrated the highest overall quality compared to the control and other treatments. Therefore, the application of these treatments is recommended for maintaining the quality of sapodilla fruit.

Objectives. To develop a method to obtain a hydrosol of the salt of chitosan with sulfuric acid—chitosanium sulfate (ChS) hydrosol—and to study the effect of various water-soluble polysaccharides on its stability over time, as well as its resistance to indifferent and non-indifferent electrolytes.Methods. κ-Carrageenan, sodium alginate (SA), and xanthan were used as polymers which perform the function of colloidal protection for ChS nanoparticles. Capillary viscometry was used to study the viscosity of polymer solutions, their molecular weight, and their adsorption on ChS. The stability of the sols over time and their resistance to indifferent and non-indifferent electrolytes were evaluated photometrically. The hydrosol particle size was determined by means of dynamic light scattering.Results. On the surface of ChS, κ-carrageenan is adsorbed most strongly over a wide range of concentrations. The graphs of the dependencies of the relative change in the turbidity of sols with the addition of various polysaccharides on their weight concentration at a sol lifetime of 2 days have the shape of curves with a maximum. Sols with the addition of 0.0125% SA and κ-carrageenan in the range of 0.04% have the greatest stability over time. According to dynamic light scattering data, the average particle size of freshly prepared sols with the addition of the polymers to ensure their greatest stability over time are 10.8 nm and 14.6 nm, respectively. For freshly prepared sols without polysaccharides, this size is 24.8 nm. The hydrosol coagulation threshold with an indifferent electrolyte (NaCl) is 9.3 times higher than that with a non-indifferent electrolyte (Na2SO4). κ-Carrageenan and SA protect the hydrosol from coagulation with an indifferent electrolyte (NaCl) at all their used amounts. At the same polymer concentrations, no protection from coagulation with a non-indifferent electrolyte (Na2SO4) was observed.Conclusions. A method was developed to obtain ChS hydrosol with a positive particle charge. The stability of ChS sols over time was studied both without and with the addition of SA, κ-carrageenan, and xanthan. Sol coagulation thresholds with indifferent and non-indifferent electrolytes, as well as the protective numbers for κ-carrageenan and SA against the coagulation of hydrosols with these electrolytes, were established. The mechanism of stability of sols at certain concentrations of water-soluble polysaccharides was explained using data on the adsorption of these polysaccharides on the surface of chitosan treated with a solution of sulfuric acid. Based on the results of the work, it can be concluded that SA and κ-carrageenan can be used for the efficient stabilization of ChS hydrosols over time and for the colloidal protection of ChS from coagulation with sodium chloride.

Wastewaters, as the major waste stream of the wine industry, are usually disposed in crude form due to the lack of sustainable treatments, which poses rising environmental threat. Considering biodegradability, nutrients content and other specific characteristics, winery wastewaters are suitable for utilization in xanthan production. In this study, the screening of local wild-type Xanthomonas euvesicatoria strains, isolated from pepper leaves, for xanthan production on medium containing wastewaters from rose wine industry, with initial sugar content of 25 g/L, was performed. Bioprocess success was estimated based on the quantity and quality of separated biopolymer. Additionally, composition of collected wastewaters was determined, and the obtained data indicate the importance of their proper management. The results of screening experiments suggest that applied X. euvesicatoria isolates have a statistically significant effect on xanthan concentration in cultivation medium, its molecular weight, as well as on apparent viscosity of xanthan aqueous solution. According to the obtained results, xanthan concentration varied from 4.0 g/L to 10.0 g/L, while the values of average molecular weight of xanthan and apparent viscosity of its solution ranged from 2.5 ∙ 105 g/mol to 8.5 ∙ 105 g/mol and from 40 mPa ∙ s to 60 mPa ∙ s, respectively. The results from this study suggest that X. euvesicatoria PL2 isolate showed the greatest potential for xanthan production on medium containing wastewaters from rose wine industry because of determined quantity of good-quality biopolymer. Further research is necessary in order to improve proposed bioprocess as sustainable biotechnological solution for winery wastewaters utilization. [ABSTRACT FROM AUTHOR]

This study examines five benzyl alcohol derivatives and three chemically similar compounds and compares them against benzyl alcohol in gelled emulsions for the removal of overpaint during cleaning of oil paintings. Comparative cleaning tests using xanthan gels, Pemulen® TR-2 gels, and neat solvent were made on overpaint on fragments of a seventeenth-century test painting. This approach demonstrated that molecular changes to a benzyl alcohol core resulted in enhanced control during the cleaning process. In some cases a benzyl alcohol derivative enabled selective removal of non-original material, when benzyl alcohol appeared to affect the original paint. Select derivatives were also tested in an area of overpaint on a sixteenth-century oil on panel painting by Jan van Scorel in the Rijksmuseum Collection through modifying the chemical activity of benzyl alcohol. Finally, two GC-MS-based methods were used to monitor benzyl alcohol retention and possible oxidation in paint layers post-treatment. [ABSTRACT FROM AUTHOR]

This review explores the novel perspectives and application of xanthan in the removal of emerging water contaminants. Xanthan is a nontoxic, biocompatible, and biodegradable biopolymer of microbial origin. Industrial production of xanthan is usually conducted by aerobic submerged batch cultivation of the bacterium Xanthomonas campestris ATCC 13951 on the medium containing glucose or sucrose under optimal conditions, and findings of researchers worldwide indicate that xanthan can be successfully biosynthesized on media containing different waste streams, using various Xanthomonas strains. Common application of xanthan is in the food industry as a stabilizer, thickener, and emulsifier because of its high viscosity at lower concentrations and excellent solubility in hot and cold water. The application of xanthan is not only limited to the food and other branches of industry, but also to medicine, biomedical engineering, agriculture, and wastewater treatment. Recent studies have confirmed the excellent photocatalytic activity and emulsifying capacity of xanthan biosynthesized on waste-based media, which offers promising potential for its application in the decontamination of environment. Moreover, the xanthan-based hydrogel has great selectivity for the cationic dye and on the other side, chemically modified xanthan has a great potential as an adsorbent for the removal of metal ions. [ABSTRACT FROM AUTHOR]

The antifungal agent, ketoconazole, and the anti-inflammatory drug, piroxicam, were incorporated into matrices of xanthan or oleic acid-esterified xanthan (Xn) and polyurethane (PU), to develop topical drug delivery systems. Compared to matrices without bioactive compounds, which only showed a nominal compressive stress of 32.18 kPa (sample xanthan–polyurethane) at a strain of 71.26%, the compressive resilience of the biomaterials increased to nearly 50.04 kPa (sample xanthan–polyurethane–ketoconazole) at a strain of 71.34%. The compressive strength decreased to around 30.67 kPa upon encapsulating a second drug within the xanthan–polyurethane framework (sample xanthan–polyurethane–piroxicam/ketoconazole), while the peak sustainable strain increased to 87.21%. The Weibull model provided the most suitable fit for the drug release kinetics. Unlike the materials based on xanthan–polyurethane, those made with oleic acid-esterified xanthan–polyurethane released the active ingredients more slowly (the release rate constant showed lower values). All the materials demonstrated antimicrobial effectiveness. Furthermore, a higher volume of piroxicam was released from oleic acid-esterified xanthan–polyurethane–piroxicam (64%) as compared to xanthan–polyurethane–piroxicam (44%). Considering these results, materials that include polyurethane and either modified or unmodified xanthan showed promise as topical drug delivery systems for releasing piroxicam and ketoconazole. [ABSTRACT FROM AUTHOR]

Cationic surfactant (CS) is one of the alarming emerging contaminants often found in municipal and industrial wastewater. Various research articles have already reported about the toxicity of CS. In the current research work, sustainable and green alginate (Ag) and alginate composite beads with xanthan gum (AgX) are explored for the adsorptive elimination of model CS, cetylpyridinium chloride (CPC) and cetyltrimethylammonium bromide (CTAB), from wastewater. The composite (AgX) beads showed relatively better performance than Ag beads in terms of mechanical strength and equilibrium time. Studies on FTIR spectra, SEM analysis, size distribution, pHzpc measurement, and elemental analyses were conducted in order to characterize the adsorbent and to get an insight into the adsorption phenomenon. At the end of 8 days' equilibrium time, the maximum adsorptive retention capacity of the AgX beads was obtained as ~ 310 mg/g with an initial CPC concentration of 600 mg/L, using an adsorbent dose of 1.5 g/L. A layered isotherm with varying slopes was obtained, indicating different stages of CPC adsorption. CPC uptake by hydrogel beads was associated with significant shrinkage of the beads. Removal of CPC from real wastewater was possible with good efficiency. The effect of pH and interfering ions on CPC removal was examined. The results showed that the pH range of 5.5–6 was the optimum, and there was no interference from Co(II), Ni(II), and Mg(II) ions. The results showed good reproducibility with a relative standard deviation (RSD) < ± 10%. [ABSTRACT FROM AUTHOR]

As oil reserves are depleted during the development of an oil deposit in an elastic-water-pressure mode, the water cut of the fluid gradually increases, reducing the efficiency of waterflooding and maintaining reservoir pressure by the system of injection wells. The rheological characteristics of the saturating fluid and the structure of the reservoir affect the likelihood of premature watering of production wells. To increase oil production and level the displacement front, various polymer systems, both synthetic and biological, are used to promote additional oil production from previously untapped reservoir zones. There are technologies for both constant injection of a working agent with a polymer, and a slug of a polymer solution of a certain concentration with subsequent injection of water. The purpose of this work is to assess the effect of injection of xanthan solution on the oil displacement efficiency with subsequent injection of formation water. An experimental (laboratory) study was carried out on alternating injection of xanthan and formation water solutions to increase filtration resistance in flooded filtration channels. Inhomogeneous terrigenous core samples with different fracturing and filtration-capacitive properties were selected as a physical model for carrying out the experiments. The main results of the laboratory study are the dependence of the oil recovery factor and water cut on the injected volume of formation water. It is noted that the key factor in reducing the displacement efficiency after injection of a polymer slug is the loss of polymer molecules both after adsorption on the rock and during further filtration of formation water through diffusion. As a result of the experimental study, it was revealed that changing the filtration rate can have a beneficial effect on the involvement of oilsaturated rock in the displacement process due to the sealing of watered areas when the injection pressure changes.

Xanthan is a natural polysaccharide in powder form, created through the fermentation of sugar by the bacteria Xanthomonas campestris. In construction, Xanthan has been researched and applied in road and bridge construction materials, viscosity adjusting additives in selfcompacting concrete... and in construction materials technology in general, Xanthan is used as a viscosity modifier, thickener... in concrete. In this study, the applicability of Xanthan in concrete was preliminarily evaluated. Through the results of squeeze - tack experiments to evaluate the rheological behavior of Xanthan pastes, the author conducted a compression test with concrete using Xanthan additive (2%), evaluating the change in strength of concrete when using Xanthan. The results show that Xanthan can be used in concrete to improve adhesion to the mold and increase the ability to easily peel off the mold. At the same time, using Xanthan in concrete with a content of 2% also contributes to increasing the compressive strength of concrete with an increase of 7%.

A new strain of xanthan-degrading bacteria identified as Cohnella sp. has been isolated from a xanthan thickener for food production. The strain was able to utilize xanthan as the only carbon source and to reduce the viscosity of xanthancontaining medium during cultivation. Comparative analysis of the secretomes of Cohnella sp. after growth on different media led to the identification of a xanthanase designated as CspXan9, which was isolated after recombinant production in Escherichia coli. CspXan9 could efficiently degrade the β-1,4-glucan backbone of xanthan after previous removal of pyruvylated mannose residues from the ends of the native xanthan side chains by xanthan lyase treatment (XLTxanthan). Compared with xanthanase from Paenibacillus nanensis, xanthanase CspXan9 had a different module composition at the N- and C-terminal ends. The main putative oligosaccharides released from XLT-xanthan by CspXan9 cleavage were tetrasaccharides and octasaccharides. To explore the functions of the Nand C-terminal regions of the enzyme, truncated variants lacking some of the non-catalytic modules (CspXan9-C, CspXan9-N, CspXan9-C-N) were produced. Enzyme assays with the purified deletion derivatives, which all contained the catalytic glycoside hydrolase family 9 (GH9) module, demonstrated substantially reduced specific activity on XLT-xanthan of CspXan9-C-N compared with fulllength CspXan9. The C-terminal module of CspXan9 was found to represent a novel carbohydrate-binding module of family CBM66 with binding affinity for XLT-xanthan, as was shown by native affinity polyacrylamide gel electrophoresis in the presence of various polysaccharides. The only previously known binding function of a CBM66 member is exo-type binding to the non-reducing fructose ends of the β-fructan polysaccharides inulin and levan. [ABSTRACT FROM AUTHOR]

This study delves into the properties and behavior of xanthan TNCS-ST, a specialized variant designed for enhanced oil recovery (EOR) purposes. A notable aspect of this polymer is its transparency and capability to dissolve in high salt concentrations, notably up to 18% total dissolved solids. Various laboratory methods are employed to assess the polymer's distinctive traits, including transparency, salt tolerance, and high pyruvylation. These methods encompass preparing xanthan solutions, conducting filtration tests, assessing energy consumption, and measuring rheological properties. The findings highlight the influence of salt concentration on xanthan's filterability, indicating increased energy requirements for dissolution with higher salt and xanthan concentrations. Additionally, this study observes temperature-dependent viscosity behavior in different solutions and evaluates the shear stability of xanthan. A significant and novel characteristic of TNCS-ST is its high salt tolerance, enabling complete dissolution at elevated salt concentrations, thus facilitating the filterability of the xanthan solution with sufficient time and energy input. Core flooding experiments investigate fluid dynamics within porous rock formations, particularly sandstone and carbonate rocks, while varying salinity. The results underscore the substantial potential of the new xanthan polymer, demonstrating its ability to enhance oil recovery in sandstone and carbonate rock formations significantly. Remarkably, the study achieves a noteworthy 67% incremental recovery in carbonate rock under the high salinity level tested, suggesting promising prospects for advancing enhanced oil recovery applications. [ABSTRACT FROM AUTHOR]

This study involved conducting an experimental investigation into the flow properties of different petrol oil–macromolecule material emulsions with regard to their viscous and elastic behaviors to assess the performance of the two most used polymers, Alcoflood and Xanthan, in the enhanced oil recovery (EOR) stage. Rheostress RS100, equipped with a cone-plate device, was employed to conduct these experiments and analyze the results. Moreover, the study involved comparing the emulsion flow in the presence of Alcoflood and Xanthan in terms of complex, storage, and loss moduli (G*, G`, and G``, respectively). Thirty-two different experimental samples of oil–Alcoflood and oil–Xanthan emulsions were prepared to cover a wide range of polymer (0–104 ppm) and petrol oil concentrations (0 –75 % by volume). A detailed examination of the viscoelastic profiles of the petrol oil macromolecule emulsions was performed over a wide frequency range from 0.1 to 10 s-1. All viscoelastic tests for both types of emulsions were conducted under a stress effect of 1 Pa to ensure that these tests were performed within the linear viscoelastic range. For a lower polymer concentration of 500 ppm, both AF1235 and Sigma oil emulsions exhibited linear viscous profiles with virtually identical G* of 50.8 Pa at a frequency of 1 s-1. However, when the polymer concentration was increased to 5000 ppm, all emulsions demonstrated viscoelastic profiles, with Sigma emulsions substantially surpassing the corresponding AF1235 blends. In the case of a 25 % oil–5000 ppm polymer mixture, the Sigma emulsion shows a G* of 827.9 Pa, whereas the AF1235 blend displays a G* of 371.9 Pa at 1 s-1. All tested emulsions of both polymers exhibit a higher elastic behavior than their corresponding viscous profile. The elastic response of the Sigma emulsions is much higher than that of the AF1235 blends. Both the elastic and viscous behaviors increase gradually with the addition of petrol oil. The current study recommends the use of xanthan gum for EOR under high shear conditions owing to its superior resistance compared to that of the Alcoflood polymer. However, the Alcoflood polymer has revealed better results in terms of sweep and oil extraction.

The primary aim was to observe the effect of processing type and compositional change on the antioxidant activity of the aqueous phase of O/W nano-emulsions during freeze-drying microencapsulation. So, olive oil-in-bitter orange juice nano-emulsions (O/W) were microencapsulated by freeze-drying with chia gum and xanthan gum. Physical (microstructure, droplet size, particle size distribution) and chemical (total antioxidant activity, total phenolic content, and structural characterization; FTIR spectroscopy) properties of different processed nano-emulsions were investigated. Solely freeze-drying of Tween80/Span20, Tween80/SMP, and Tween80/SL nano-emulsions caused a 39%, 13%, and 19% decrease in antioxidant activity accompanied by 65%, 52%, and 64% decrease in phenolic content, respectively. Microencapsulation with xanthan gum increased antioxidant activity of Tween80/Span20, Tween80/SMP, and Tween80/SL nano-emulsions by 17%, 47%, and 120% accompanied by a 5.8, 7.2, and 5.9 times rise in phenolic content, respectively. Microencapsulation with chia gum produced a 7.5, 7.13, and 9.3 times increase in antioxidant activity along with a 9.3, 12.4, and 10.1 times rise in phenolic content of Tween80/Span20, Tween80/SMP, and Tween80/SL nano-emulsions, respectively. Freeze-drying microencapsulation with chia gum and xanthan gum can be an effective method for increasing the antioxidant activity of the aqueous phase of O/W nano-emulsions. [ABSTRACT FROM AUTHOR]

A framework was developed to evaluate and compare cleaning systems and cleaning system delivery methods, collectively referred to as varnish removal methods, within art conservation practice. This framework was applied to two water-based cleaning systems, optimised for the removal of dammar varnish from an artificially aged brown earth oil paint, including the surfactant-containing microemulsion, Polar Coating B (from the Nanorestore Cleaning series) delivered via the chemical gel, Higher Water Retention (HWR) (from the Nanorestore Gel Dry series), and a surfactant-free microemulsion delivered via the microfiber cloth, Evolon. In addition, two water-based systems and one organic solvent were used to remove dammar varnish from an artificially aged lead white oil paint sample, including a xanthan gum-stabilised emulsion delivered via a synthetic brush, a surfactant-free microemulsion delivered via cotton swab rolling, and 2-propanol solvent delivered via cotton swab rolling. The evaluation framework was thus applied to two different oil paints, with different sensitivities to cleaning. Through this work, the comparative advantages and disadvantages of the varnish removal methods were demonstrated. Notably, cleaning system compatibility with multiple delivery methods afforded greater versatility, including for reducing unwanted interactions between the cleaning system and oil paint. In addition, a surfactant-free microemulsion proved to be a promising, clearance-free, inexpensive, and modifiable option within current offerings for largely water-based methods for varnish removal. [ABSTRACT FROM AUTHOR]

Photodynamic therapy using delta-aminolevulinic acid is considered a promising option in the treatment of oral lichen planus. In the present work, three emulgel compositions prepared from natural polysaccharide gums, tragacanth, xanthan and gellan, were preliminarily tested for oromucosal delivery of delta-aminolevulinic acid. Apart from cytotoxicity studies in two gingival cell lines, the precise goal was to investigate whether the presence of the drug altered the rheological and mucoadhesive behavior of applied gelling agents and to examine how dilution with saliva fluid influenced the retention of the designed emulgels by oromucosal tissue. Ex vivo mucoadhesive studies revealed that a combination of xanthan and gellan gum enhanced carrier retention by buccal tissue even upon dilution with the saliva. In turn, the incorporation of delta-aminolevulinic acid favored interactions with mucosal tissue, particularly formulations comprised of tragacanth. The designed preparations had no significant impact on the cell viability after a 24 h incubation in the tested concentration range. Cytotoxicity studies demonstrated that tragacanth-based and gellan/xanthan-based emulgels might exert a protective effect on the metabolic activity of human gingival fibroblasts and keratinocytes. Overall, the presented data show the potential of designed emulgels as oromucosal platforms for delta-aminolevulinic acid delivery. [ABSTRACT FROM AUTHOR]

为了进一步促进我国核桃资源优势向经济效益优势转化，提高核桃饼粕中蛋白质的高值化利用，以核桃饼中提取的核桃蛋白作为原料，通过与黄原胶复配制备一种蛋白-多糖复合的Pickering乳液，通过单因素实验和响应面实验对核桃粕蛋白-黄原胶复合Pickering乳液的制备工艺进行了优化,并考察了制备的Pickering乳液的热稳定性、冷藏稳定性和冻融稳定性。结果表明，核桃蛋白-黄原胶复合Pickering乳液制备的最优工艺参数为pH 6.5、黄原胶添加量0.2 g/100 mL、核桃油体积分数72%，在此条件下乳液乳析指数较低，为（1.49±0.68）%,乳液体系热稳定和冷藏稳定性较好，冻融稳定性较差。综上，制备核桃蛋白-黄原胶复合Pickering乳液为核桃蛋白的开发利用提供了一个新思路。 In order to further promote the transformation of walnut resources advantage to economic benefit advantage and improve the high-value utilization of protein in walnut meal, a protein-polysaccharide composite Pickering emulsion was prepared by walnut protein and xanthan. The preparation process of walnut protein-xanthan composite Pickering emulsion was optimized by single factor experiment and response surface experiment, and the thermal stability, frozen stability, freeze-thaw stability were determined. The results showed that the optimal preparing parameters of Pickering emulsion were pH 6.5, xanthan dosage 0.2 g/100 mL, walnut oil volume fraction 72%. Under these conditions, the creaming index was lower with (1.49±0.68)%. The emulsion system had good thermal stability and frozen stability, but the freeze-thaw stability was low. In conclusion, the preparation of walnut protein-xanthan composite Pickering emulsion provides a new idea for the exploitation of walnut protein.

Graft copolymers of polysaccharides with acrylic monomers combine biodegradability, biocompatibility, the environmental friendliness of natural polymers and the increased thermal stability, chemical and mechanical resistance of synthetic polymers. This paper describes our search and analysis of the literature in English for 2002–2022 devoted to the graft polymerization of acrylamide, acrylic acid and 2-acrylamido2-methylpropanesulfonic acid onto xanthan and glucomannan macromolecular chains. It has been found that the synthesis of grafted copolymer chains proceeds by a radical polymerization mechanism using thermal homolytic decomposition of the initiator or microwave irradiation, or radiation initiation and frontal polymerization in some cases. Depending on the method of the reaction, the synthesis time of a graft copolymer varies from several minutes to several hours. The infl uence of the synthesis conditions and parameters on the monomer conversion, structure and properties of the resulting polymer has been considered. It has been found that decreasing the polysaccharide/monomer ratio and increasing the initiator concentration raise the effi ciency and degree of grafting. Several methods for characterization of graft copolymers are discussed, including: IR spectroscopy to analyze the chemical structure of a sample, scanning electron microscopy to characterize structure, supramolecular ordering and porosity, diff erential thermal analysis to evaluate thermal eff ects and thermal stability. The eff ect of the synthesis conditions and the pH of the sorption medium on the water absorption and sorption capacity of this class of graft copolymers are discussed. The broad potential of graft copolymers for repeated cycles of absorption and release of liquid medium without loss of functional properties has been found. This opens prospects for the use of graft copolymers of xanthan and glucomannan with acrylic monomers as materials for water purifi cation from metal ions and cationic dyes, targeted delivery and prolonged action of drugs and wound coatings for wound treatment.

The inadequate existence of practical techniques for water purification poses a prominent and widespread global environmental challenge. This study aims to clarify the efficacy of xanthan application in the photocatalytic removal of nadolol, pindolol, and cefoperazone from water reservoirs. Under the influence of a simulated solar light source, xanthan exhibited significant degradation rates for pindolol (77%) and cefoperazone (91%). In contrast, nadolol's degradation efficiency was notably lower (10%). These findings suggest that the molecular structure can substantially influence the efficiency of the purification process. Computational analyses were conducted to gain a more profound understanding of the implications of molecular structure.

This study aimed to increase the physical stability of native sunflower oleosomes to expand their range of applications in food. The first objective was to increase the stability and functionality of oleosomes to lower pH since most food products require a pH of 5.5 or lower for microbial stability. Native sunflower oleosomes had a pI of 6.2. One particularly effective strategy for long-term stabilization, both physical and microbial, was the addition of 40% (w/w) glycerol to the oleosomes plus homogenization, which decreased the pI to 5.3 as well as decreasing oleosome size, narrowing the size distribution and increasing colloidal stability. Interfacial engineering of oleosomes by coating them with lecithin and the polysaccharides xanthan and gellan, effectively increased stability, and lowered their pI to 3.0 for lecithin and lower than 3.0 for xanthan. Coating oleosomes also caused a greater absolute value of the ζ-potential; for example, this amount was shifted to −20 mV at pH 4.0 for xanthan and to −28 mV at pH 4.0 for lecithin, which provides electrostatic stabilization. Polysaccharides also provide steric stabilization, which is superior. A significant increase in the diameter of coated oleosomes was observed with lecithin, xanthan and gellan. The oleosome sample with 40% glycerol showed high storage stability at 4 °C (over three months). The addition of glycerol also decreased the water activity of the oleosome suspension to 0.85, which could prevent microbial growth.

Photodynamic therapy (PDT) recently has been shown as a promising option in the treatment of premalignant lesions of the soft oral tissues. Effective delivery of photosensitizer is challenging due to poor drug adherence to the oromucosal epithelium. In the present work, emulgels composed of natural polysaccharide gums (tragacanth, xanthan and gellan) were evaluated as novel oromucosal platforms of delta-aminolevulinic acid (ALA) for PDT. Apart from mucoadhesive and textural analysis, the specific steps involved studies on drug penetration behavior and safety profile using a three-dimensional human oral epithelium model (HOE). All designed emulgels presented greater mucoadhesiveness when compared to commercial oromucosal gel. Incorporation of ALA affected textural properties of emulgels, and tragacanth/xanthan formulation with greater hardness and cohesiveness exhibited a protective function against the mechanical tongue stress. Permeability studies revealed that ALA is capable of penetrating across oromucosal epithelium by passive transport and all formulations promoted its absorption rate when compared to a commercial topical product with ALA. Importantly, the combination of tragacanth and xanthan profoundly enhanced photosensitizer retention in the buccal epithelium. Tested samples performed negligible reduction in cell viability and moderately low IL-1β release, confirming their non-irritancy and compatibility with HOE. Overall, the presented findings indicate that tragacanth/xanthan emulgel holds promise as an oromucosal ALA-carrier for PDT strategy. [ABSTRACT FROM AUTHOR]

Recently, degradable biopolymers have become increasingly important as potential environmentally friendly biomaterials, providing a wide range of applications in various fields. Bacterial exopolysaccharides (EPSs) are biomacromolecules, which due to their unique properties have found applications in biomedicine, foodstuff, textiles, cosmetics, petroleum, pharmaceuticals, nanoelectronics, and environmental remediation. One of the important commercial polysaccharides produced on an industrial scale is xanthan. In recent years, the range of its application has expanded significantly. Bacterial cellulose (BC) is another unique EPS with a rapidly increasing range of applications. Due to the great prospects for their practical application, the development of their highly efficient production remains an important task. The present review summarizes the strategies for the cost-effective production of such important biomacromolecules as xanthan and BC and demonstrates for the first time common approaches to their efficient production and to obtaining new functional materials for a wide range of applications, including wound healing, drug delivery, tissue engineering, environmental remediation, nanoelectronics, and 3D bioprinting. In the end, we discuss present limitations of xanthan and BC production and the line of future research. [ABSTRACT FROM AUTHOR]

This study aims to produce fat‐reduced cream cheese using the different levels (0.25%–0.5%) of basil seed and xanthan gum by a RSM method. The basil seed, xanthan gum, and fat levels did not significantly influence the cream cheese's pH and acidity. With the fat reduction, textural properties were lost; for example, hardness, gumminess, and adhesiveness increased, and cohesiveness decreased. In addition, low‐fat cream cheese's sensory score (taste, mouthfeel, and overall acceptance score) was lower. However, adding basil seed and xanthan gum could improve water holding capacity (WHC), hardness, gumminess, cohesiveness, adhesiveness and scores of mouthfeel, and overall acceptance. Basil seed gum had a better impact than xanthan on fat‐reduced cream cheese properties among the two gums. In general, results showed that adding 0.5% basil and 0.5% xanthan into cream cheese could manufacture a product with a reduced‐fat level (19.04%). At the same time, its physicochemical, sensory, and textural attributes were similar to cream cheese with high fat (24%). In addition, the price of the obtained product was lower. [ABSTRACT FROM AUTHOR]

Xanthan is an extracellular heteropolysaccharide produced by the bacteria Xanthomonas campestris. Due to its unique properties, the polysaccharide and its derivatives are widely used in many industries, from food to biomedicine and oil production, that demands an efficient xanthan depolymerization method to adapt this polysaccharide for various applications. Unlike the known chemical approaches, biological methods are considered to be more environmentally friendly and less energy intensive. In laboratory conditions, we have isolated a bacterial community capable of reducing the xanthan viscosity. Identification of the individual isolates in the microbial community and their testing resulted in the consortium LE-C1, consisting of two microorganisms Paenibacillus phytohabitans KG5 and Cellulosimicrobium cellulans KG3. The specific activities of the overall xanthanase and auxiliary enzymes that may be involved in the xanthan depolymerization were as follows: xanthanase, 19.6 ± 0.6 U/g; β-glucosidase, 3.4 ± 0.1 U/g; α-mannosidase, 68.0 ± 2.0 U/g; β-mannosidase, 0.40 ± 0.01 U/g; endo-glucanase, 4.0 ± 0.1 U/g; and xanthan lyase, 2.20 ± 0.07 U/mg. In order to increase the efficiency of xanthan biodegradation, the LE-C1 whole cells were immobilized in a poly(vinyl alcohol) cryogel. The resulting regenerative biocatalyst was able to complete xanthan depolymerization within 40 cycles without loss of activity or degradation of the matrix. [ABSTRACT FROM AUTHOR]

Objective: This study was designed to show the effect of adding different levels of microbial (lab-produced) and commercial xanthan (CX) for 30 days on the sensory, chemical, and microbiological parameters of mozzarella cheese (MC). Materials and Methods: The production of xanthan was done in Garcia-Ochoa's medium. The sensory evaluation of the examined MC was achieved through a tabulated scorecard. The Gerber method was used for the determination of MC fat%. The mean counts of staphylococci [colony forming unit (CFU)/gm], coliforms (most probable number/gm), fungi (CFU/gm), and mesophilic bacteria (CFU/gm) were estimated in different fortified cheeses. Also, mean counts of Escherichia coli O157 and Staphylococcus aureus in artificially contaminated MC were determined. Results: The microbial xanthan (MX) had a significant (p < 0.05) effect on the sensory parameters of the examined samples with its concentration (0.0007%) after 20 days of storage. The MX (0.0005%) and CX (0.0002%) had a significant effect on moisture, fat in dry matter, and protein percentage of MC throughout the storage period. The high meltability degree of MC was observed in samples with both types of xanthan (0.0002%) at the end of storage. Conclusion: Both types of xanthan at all concentrations had a significant reducing effect on E. coli O157 and S. aureus in all samples from 10 to 30 days of storage. Xanthan has accepted attentiveness and offers beneficial and safe characteristics that improve its adaptability in MC. In the Middle East, this survival trial of E. coli O157 and S. aureus in the MC supplemented by xanthan is considered a scarce exploratory investigation. [ABSTRACT FROM AUTHOR]

Traditional soil stabilization techniques, such as cement and lime, are known for their menacing effect on the environment through heavy carbon emissions. Sustainable soil stabilization methods are grabbing attention, and the utilization of biopolymers is surely one among them. Recent studies proved the efficiency of biopolymers in enhancing the geotechnical properties to meet the requirements of the construction industry. The suitability of biopolymer application in different soils is still unexplored, and the carbon footprint analysis (CFA) of biopolymers is crucial in promoting the biopolymers as a promising sustainable soil stabilization method. This study attempts to investigate the out-turn of cross-linked biopolymer on soils exhibiting different plasticity characteristics (Medium & High compressibility) and to determine the Embodied carbon factor (ECF) for the selected biopolymers. Guar (G) and Xanthan (X) biopolymers were cross-linked at different proportions to enhance the geotechnical properties of soils. Atterberg's limits, Compaction characteristics, and Unconfined Compressive Strength were chosen as performance indicators, and their values were analyzed at different combinations of biopolymers before and after cross-linking. The test results have shown that Atterberg's limits of the soils increased with the addition of biopolymers, and it is attributed to the formation of hydrogels in the soil matrix. Compaction test results reveal that the Optimum Moisture Content (OMC) of biopolymer-modified soil increased, and Maximum Dry Density (MDD) reduced due to the resistance offered by hydrogel against compaction effort. Soils amended with biopolymers and cured for 14, 28, and 60 days have shown an appreciable improvement in Unconfined Compressive Strength (UCS) results. Microlevel analysis was carried out using SEM (Scanning Electron Microscopy) and FTIR (Fourier-transform infrared spectroscopy) to formulate the mechanism responsible for the alteration in targeted performance indicators due to the cross-linking of biopolymers in the soil. The embodied energy in the production of both Guar and Xanthan biopolymers was calculated, and the obtained ECF values were 0.087 and 1.67, respectively. [ABSTRACT FROM AUTHOR]

Xanthomonas vesicatoria is one of the causal agents of bacterial spot, a disease that seriously affects the production of tomato (Solanum lycopersicum) and pepper (Capsicum annum) worldwide. In Argentina, bacterial spot is found in all tomato producing areas, with X. vesicatoria being one of the main species detected in the fields. Previously, we isolated three X. vesicatoria strains BNM 208, BNM 214, and BNM 216 from tomato plants with bacterial spot, and found they differed in their ability to form biofilm and in their degree of aggressiveness. Here, the likely causes of those differences were explored through genotypic and phenotypic studies. The genomes of the three strains were sequenced and assembled, and then compared with each other and also with 12 other publicly available X. vesicatoria genomes. Phenotypic characteristics (mainly linked to biofilm formation and virulence) were studied in vitro. Our results show that the differences observed earlier between BNM 208, BNM 214, and BNM 216 may be related to the structural characteristics of the xanthan gum produced by each strain, their repertoire of type III effectors (T3Es), the presence of certain genes associated with c-di-GMP metabolism and type IV pili (T4P). These findings on the pathogenicity mechanisms of X. vesicatoria could be useful for developing bacterial spot control strategies aimed at interfering with the infection processes. [ABSTRACT FROM AUTHOR]

This investigation was carried out to study the effect of three types of gums namely: Arabic gum (AG), guar gum (GG) and xanthan gum (XG) as well as different water amounts on the physical, sensory, and textural properties of glutenfree pan bread (GFPB). The gluten-free composite flour as base formulation consists of 47.5g rice flour, 47.5g cornstarch, and 5g skim milk powder. Firstly, AG, GG and XG were tested, separately, with constant concentration (2g) and at three different amounts of water (90, 100, and 110 ml). The results indicated that the use of XG significantly increase the specific volume, High/Width ratio and yield of GFPB whereas the baking loss decrease with increasing of water amount used. However, these parameters were diminished in the case of AG and GG by using high amount of water (110 ml). The texture profile analysis (TPA) data indicated that hardness and cohesiveness decreased, while springiness and resilience increased with increasing the water amount. Secondly, three different concentrations 2, 3 and 4g of each gum, separately, were tested with a constant amount of water (110 ml). The obtained results showed that the increase of AG or GG concentration led to enhancement of GFPB specific volume. In contrast, the increase of XG from 2 to 4g with the water amount of 110 ml caused decrease in the specific volume. The TPA data showed that higher doses of gum tended to produce breads with higher hardness, gumminess, chewiness and lower springiness. Moreover, the increasing in water amount resulted in softer, spongier and more resilient crumbs. Good physical, textural and sensory acceptable was obtained with formulation supplemented with 2g XG and 110 ml water. [ABSTRACT FROM AUTHOR]

Copyright of Iraq Journal of Market Research & Consumer Protection / Al-Mağallaẗ al-ʿIrāqiyyaẗ li-Buḥūṯ al-Sūq wa-Ḥimāyaẗ al-Mustahlik is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The use of polysaccharides with good film-forming properties in food packaging systems is a promising area of research. Xanthan gum (XG), an extracellular polysaccharide, has many industrial uses, including as a common food additive (E415). It is an effective thickening agent, emulsifier, and stabilizer that prevents ingredients from separating. Nevertheless, XG-based polymer films have some disadvantages, such as poor mechanical properties and high hydrophilic features, which reduce their stability when exposed to moisture and create difficulties in processing and handling. Thus, the objective of this work was to stabilize a XG matrix by cross-linking it with glycerol diglycidyl ether, 1,4-butanediol diglycidyl ether, or epichlorohydrin below the freezing point of the reaction mixture. Cryogelation is an ecological, friendly, and versatile method of preparing biomaterials with improved physicochemical properties. Using this technique, XG-based cryogels were successfully prepared in the form of microspheres, monoliths, and films. The XG-based cryogels were characterized by FTIR, SEM, AFM, swelling kinetics, and compressive tests. A heterogeneous morphology with interconnected pores, with an average pore size depending on both the nature of the cross-linker and the cross-linking ratio, was found. The use of a larger amount of cross-linker led to both a much more compact structure of the pore walls and to a significant decrease in the average pore size. The uniaxial compression tests indicated that the XG-based cryogels cross-linked with 1,4-butanediol diglycidyl ether exhibited the best elasticity, sustaining maximum deformations of 97.67%, 90.10%, and 81.80%, respectively. [ABSTRACT FROM AUTHOR]

Intensive development of the global biodiesel industry has led to the generation of a large excess of crude glycerol, which is impure, and its disposal into the environment is unacceptable without previous purification. Since purification costs are high, the application of crude glycerol in biotechnological production of valueadded products represents a promising solution for a sustainable utilization of this effluent. The aim of this study was to examine xanthan biosynthesis by the Xanthomonas PL 3 strain on a medium containing crude glycerol from biodiesel production in a laboratory-scale bioreactor in order to further scale up this bioprocess. Xanthan was produced by submerged cultivation in a crude glycerol-based medium (glycerol content of 20 g/L) in a 3 L lab-scale bioreactor (working volume of 2 L), under aerobic conditions for 168 h (0-48 h: 25°C, 1 vvm and 200 rpm; 48-168 h: 30 °C, 2 vvm, and agitation rate adjusted according to the dissolved oxygen concentration which was maintained at values higher than 30%). The bioprocess was monitored by the analysis of cultivation medium samples in predetermined time intervals, and its success was estimated based on the xanthan concentration in the medium, separated biopolymer average molecular weight and degree of nutrient conversion. In the applied experimental conditions, 11.10 g/L of xanthan with the average molecular weight of 2.85·105 g/moL was biosynthesized. At the end of this bioprocess, the degree of total glycerol, nitrogen and phosphorous conversion was 62.82%, 41.54% and 24.80%, respectively. Results obtained in this study suggest that the Xanthomonas PL 3 strain has the ability to produce xanthan of good quality on cultivation media containing crude glycerol from the biodiesel industry. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian Polytechnic University is the property of Journal of Dalian Polytechnic University Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bacterial cellulose (BC) is an extracellular product of bacterial metabolism. BC has the same molecular formula as plant cellulose, but their structures are significantly different. Due to its unique properties (high degree of crystallinity, purity, good water-holding capacity), bacterial cellulose is widely used in many areas of human life. However, despite all the advantages of BC over plant polymers, its production is a relatively expensive process. Thus, one of the ways to increase the polymer yield can be the joint cultivation of a bacterial cellulose producer strain with other polysaccharide producers. From literature data, it is known that there is a positive effect of some water-soluble polysaccharides on the yield of BC. In addition, many biosynthetic genes remain silent and not expressed in vitro, thereby severely limiting the chemical diversity of microbial compounds that can be obtained by fermentation. In contrast, the cocultivation of two or more different microorganisms mimics a real "situation" where microorganisms coexist in complex microbial communities. It has been proven that competition or antagonism that occurs during cocultivation leads to a significant increase in existing compounds and/or to the accumulation of new compounds that are not found in axial cultures of the producer strain. The purpose of this work was to study cocultivation as a way to increase the yield of bacterial cellulose during the cultivation of BC producers with other polysaccharide-forming strains. The strain of Komagataeibacter sucrofermentans B-11267 was used as a BC producer, Xanthomonas campestris was used as a xanthan producer, and Leuconostoc mesenteroides was used as a dextran producer. The cultivation was carried out under dynamic conditions on a medium with molasses. The polysaccharide yield was expressed as the absolute dry weight of the polymers per unit volume of the culture medium. We have studied the morphology of bacterial cellulose using atomic force microscopy (AFM), FTIR spectroscopy. Crystallinity was checked by X-ray diffraction analysis. The interest in bacterial cellulose makes it necessary to synthesize it in large quantities on an industrial scale. The problem of increasing productivity was solved by cocultivating the bacterial cellulose producer Komagataeibacter sucrofermentans with the dextran producer Leuconostoc mesenteroides and xanthan producer Xanthomonas campestris, since the addition of water-soluble polysaccharides is known to increase viscosity of the medium and facilitate the dispersion of bacterial cellulose granules, thereby increasing the number of free cells, which can accelerate sugar consumption and polymer formation. At the first stage of the study, the selection of the most optimal conditions for cocultivation of the BC producer with the producers of xanthan and dextran was carried out, namely, the optimal pH value of the medium. Monoculture of bacteria X. campestris, L. mesenteroides, and K. sucrofermentans was carried out at different pH values (see Figs. 1–3). Based on the data obtained, it can be stated that the most optimal pH value for cocultivation of microorganisms is pH 5.0. In this regard, at the second stage of the work, joint cultivation of the BC producer strain K. sucrofermentans with the xanthan and dextran producers X. campestris and L. mesenteroides, respectively, on molasses medium was carried out. From the data presented (see Fig. 4), it can be seen that the largest amount of polysaccharide is formed on day 3 of cocultivation of the bacterial cellulose producer and the dextran producer. The amount of bacterial cellulose was 5.99 ± 0.02 g/L, i.e., two and a half times higher than the amount of polymer formed during monocultivation of the bacterial cellulose producer: 2.25 ± 0.05 g/L. Cocultivation of the bacterial cellulose producer strain with the xanthan producer did not lead to an increase in the polysaccharide yield. Therefore, no further study of cocultivation of these microorganisms was carried out. The success of joint cultivation of bacterial cellulose and dextran producer strains was assessed and the properties of the obtained polysaccharide were studied using AFM, FTIR spectroscopy, and X-ray structural analysis. The surface relief of the bacterial cellulose was studied by AFM (see Fig. 7). The analysis of AFM images showed the presence of an association of K. sucrofermentans and L. mesenteroides cells in the BC. Also, the obtained bacterial cellulose was investigated using the method of FTIR spectroscopy (see Fig. 8). The IR spectra show the similarity of the detected peaks with the literature data on the peaks corresponding to bacterial cellulose. To determine the degree of crystallinity, the structure of cellulose was studied by X-ray structural analysis (see Fig. 9). The degree of crystallinity of cellulose samples is 64 and 32% for monocultivation of K. sucrofermentans and cocultivation of K. sucrofermentans and L. mesenteroides, respectively. [ABSTRACT FROM AUTHOR]

Employing aerobic fermentation, Gram-negative bacteria belonging to the genus Xanthomonas produce the high molecular weight natural heteropolysaccharide known as xanthan. It has various amounts of O-acetyl and pyruvyl residues together with D-glucosyl, D-mannosyl, and D-glucuronyl acid residues in a molar ratio of 2:2:1. The unique structure of xanthan allowed its various applications in a wide range of industries such as the food industry, pharmacology, cosmetics and enhanced oil recovery primarily in petroleum. The cultivation medium used in the manufacture of this biopolymer is critical. Many attempts have been undertaken to generate xanthan gum from agro-based and food industry wastes since producing xanthan gum from synthetic media is expensive. Optimal composition and processing parameters must also be considered to achieve an economically viable manufacturing process. There have been several attempts to adjust the nutrient content and feeding method, temperature, pH, agitation and the use of antifoam in xanthan fermentations. Various modifications in technological approaches have been applied to enhance its physicochemical properties which showed significant improvement in the area studied. This review describes the biosynthesis production of xanthan with an emphasis on the importance of the upstream processes involving medium, processing parameters, and other factors that significantly contributed to the final application of this precious polysaccharide. [ABSTRACT FROM AUTHOR]

Bacterial exopolysaccharides (EPS) are essential natural biopolymers used in different areas including biomedicine, food, cosmetic, petroleum, and pharmaceuticals and also in environmental remediation. The interest in them is primarily due to their unique structure and properties such as biocompatibility, biodegradability, higher purity, hydrophilic nature, anti-inflammatory, antioxidant, anti-cancer, antibacterial, and immune-modulating and prebiotic activities. The present review summarizes the current research progress on bacterial EPSs including their properties, biological functions, and promising applications in the various fields of science, industry, medicine, and technology, as well as characteristics and the isolation sources of EPSs-producing bacterial strains. This review provides an overview of the latest advances in the study of such important industrial exopolysaccharides as xanthan, bacterial cellulose, and levan. Finally, current study limitations and future directions are discussed. [ABSTRACT FROM AUTHOR]

Xanthan, a bacterial polysaccharide, is widespread in industrial applications, particularly as a food additive. However, little is known about the process of xanthan synthesis on the proteome level, even though Xanthomonas campestris is frequently used for xanthan fermentation. A label-free LC-MS/MS method was employed to study the protein changes during xanthan fermentation in minimal medium. According to the reference database, 2416 proteins were identified, representing 54.75 % of the proteome. The study examined changes in protein abundances concerning the growth phase and xanthan productivity. Throughout the experiment, changes in nitrate concentration appeared to affect the abundance of most proteins involved in nitrogen metabolism, except Gdh and GlnA. Proteins involved in sugar nucleotide metabolism stay unchanged across all growth phases. Apart from GumD, GumB, and GumC, the gum proteins showed no significant changes throughout the experiment. GumD, the first enzyme in the assembly of the xanthan-repeating unit, peaked during the early stationary phase but decreased during the late stationary phase. GumB and GumC, which are involved in exporting xanthan, increased significantly during the stationary phase. This study suggests that a potential bottleneck for xanthan productivity does not reside in the abundance of proteins directly involved in the synthesis pathways.