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Abstract The market for microbial gums such as xanthan, gellan, dextran, and curdlan is continuously expanding, driven by their increasing application in various industries including petroleum, pharmaceuticals, cosmetics, and food, with the latter accounting for approximately 50% of global usage. To meet the growing demand and improve sustainability, there is a need to enhance production efficiency and reduce costs. This article addresses these issues by examining recent advancements and emerging trends in microbial gum production and application. By highlighting patented technologies and innovative approaches, the article aims to provide a comprehensive understanding of how the industry can achieve higher yields and economic viability. Despite being produced by different microorganisms, these gums are synthesized under similar conditions, such as pH, temperature, and medium composition. The purification or downstream processes for these gums are also comparable, primarily involving solvent precipitation, centrifugation for separation, and drying. Significant advances in gum production include genetic improvement of microbial strains to improve biopolymer performance. Additionally, alternative media are being explored, either by optimizing nutrient availability or deprivation, or by using agroindustrial by-products to reduce production costs. Engineering improvements are another strategy: bioreactor characteristics, fermentation conditions and modes of operation, and advances in downstream process are highlighted. Furthermore, the text explores emerging trends in the application of microbial gums in the food sector. Microbial gums applications are not limited to their traditional action as emulsifiers and stabilizers, but expands to new uses in biodegradable packaging films and as antioxidant and prebiotic food ingredient.

In order to increase the kinds of jelly and improve the added value of Phyllanthus emblica L. and passion fruit, using P. emblica L. and passion fruit as main raw materials, sensory score, color and texture properties as indicators, the effects of the added amount of passion fruit juice, compound gum and erythritol on the quality of the compound jelly of P. emblica L. and passion fruit were explored by single factor experiments. On this basis, taking sensory score as the response value, the formulation of the compound jelly of P. emblica L. and passion fruit was optimized by response surface methodology. The results showed that the best formulation of the compound jelly of P. emblica L. and passion fruit was as follows: The added amount of passion fruit juice was 19%, the added amount of compound gum was 2.0% (the mass ratio of curdlan gum, konjac gum and xanthan gum was 30:3:7), and the added amount of erythritol was 26.8%. The compound jelly prepared under these conditions was orange in color, lustrous, delicate in taste, with the characteristic flavors of P. emblica L. and passion fruit being outstanding and harmonious. It tasted sweet and sour, with long sweet aftertaste, and the hardness, elasticity and chewiness were moderate. Its overall acceptability was very good, and its sensory score was 8.65 points. This study could provide a reference for the development of low-sugar compound jelly of P. emblica L. and passion fruit without adding flavor, pigment and sucrose.

In order to increase the kinds of jelly and improve the added value of Phyllanthus emblica L. and passion fruit, using P. emblica L. and passion fruit as main raw materials, sensory score, color and texture properties as indicators, the effects of the added amount of passion fruit juice, compound gum and erythritol on the quality of the compound jelly of P. emblica L. and passion fruit were explored by single factor experiments. On this basis, taking sensory score as the response value, the formulation of the compound jelly of P. emblica L. and passion fruit was optimized by response surface methodology. The results showed that the best formulation of the compound jelly of P. emblica L. and passion fruit was as follows: The added amount of passion fruit juice was 19%, the added amount of compound gum was 2.0% (the mass ratio of curdlan gum, konjac gum and xanthan gum was 30:3:7), and the added amount of erythritol was 26.8%. The compound jelly prepared under these conditions was orange in color, lustrous, delicate in taste, with the characteristic flavors of P. emblica L. and passion fruit being outstanding and harmonious. It tasted sweet and sour, with long sweet aftertaste, and the hardness, elasticity and chewiness were moderate. Its overall acceptability was very good, and its sensory score was 8.65 points. This study could provide a reference for the development of low-sugar compound jelly of P. emblica L. and passion fruit without adding flavor, pigment and sucrose. [ABSTRACT FROM AUTHOR]

Curdlan gum (CG) is a β-(1→3)-linked glucan insoluble exopolysaccharide produced by marine bacteria Enterobacter cloacae subsp. dissolvens RSW2n. In this study, CG was used to fabricate gallic acid-encapsulated curdlan gum nanoparticles (GA-CG NPs) for effectively delivering the drug into breast cancer cells (MCF-7) using glutaraldehyde as the crosslinking agent and a modified desolvation method was adopted. The fabricated GA-CG NPs were characterized by UV–Visible spectra, FT-IR, XRD, particle size analyzer and HR-TEM. The stability of GA-CG NPs was evaluated at various pH and simulated body fluids. In vitro drug release and its kinetics were examined through the dissolution mechanism using mathematical prediction models. The encapsulation efficiency and loading capacity of gallic acid was 88.215 ± 3.242% and 8.26 ± 0.021%, respectively. The antioxidant and cytotoxic potential of GA-CG NPs were evaluated through in vitro assays. The IC50 of GA-CG NPs against MCF-7 cells was found to be 16.75 µg × mL−1. The induction of apoptosis in MCF-7 cells was confirmed through flow cytometry. Nuclei condensation, loss of mitochondrial membrane potential, and deformed cell membranes were visualized by staining. Curdlan gum effectively controls the release of gallic acid as the gel matrix slowly degrades and releases the encapsulated gallic acid. Hence, the curdlan gum produced by E. cloacae could be considered as promising candidate for drug delivery application for degenerative disorder. [ABSTRACT FROM AUTHOR]

Exopolysaccharides of marine microbial origin are in demand in industry. Seaweeds are marine macroalgae that harbor diverse microorganisms with unique properties. In this perspective, the present study was focused on screening and isolation of marine bacteria from seaweeds for the production of an exopolysaccharide, curdlan gum, which is a linear (1 → 3)-β-d-glucan neutral exopolysaccharide produced by bacteria under conditions of nitrogen starvation. It has unique thermo gelation properties and extensive applications. A total of 78 marine bacteria were screened and isolated from different seaweeds and assessed for their potential for curdlan gum production using aniline blue agar. Curdlan gum was recovered using acidic precipitation. High-yield isolate, screened from red seaweed (Gracilaria foliifera) was designated as "RSW2n" and chosen as a potential producer. The identity of the isolate RSW2n was revealed as Enterobacter cloacae subsp. dissolvens based on its morphology, biochemical characteristics, and 16S rRNA gene sequencing. Optimization of the process parameters such as initial pH, inoculum percentage, production time, and production medium volume by single factor at a time method yielded 4.2 g/L of curdlan gum using Enterobacter cloacae strain RSW2n. Characterization of curdlan gum produced by this marine isolate was carried out using XRD and FT-IR analyses. Further, production of curdlan gum by Enterobacter cloacae RSW2n with different carbon sources (glucose, sucrose, fructose, maltose, glycerol, dates syrup, palm oil and starch) was studied. [ABSTRACT FROM AUTHOR]

In this study 5-((2-((3-methoxy benzylidene)-amino)-phenyl)-diazenyl)-4,6-diphenyl pyrimidine-2(5H)-thione was synthesized. The pharmacological applications of pyrimidine analogs are restricted due to their poor pharmacokinetic properties. As a solution, a microbial exopolysaccharide (curdlan gum) was used to synthesize folic acid-conjugated pyrimidine-2(5H)-thione-encapsulated curdlan gum-PEGamine nanoparticles (FA-Py-CG-PEGamine NPs). The results of physicochemical properties revealed that the fabricated FA-Py-CG-PEGamine NPs were between 100 and 400 nm in size with a majorly spherical shaped, crystalline nature, and the encapsulation efficiency and loading capacity were 79.04 ± 0.79 %, and 8.12 ± 0.39 % respectively. The drug release rate was significantly higher at pH 5.4 (80.14 ± 0.79 %) compared to pH 7.2. The cytotoxic potential of FA-Py-CG-PEGamine NPs against MCF-7 cells potentially reduced the number of cells after 24 h with 42.27 μg × mL−1 as IC 50 value. The higher intracellular accumulation of pyrimidine-2(5H)-thione in MCF-7 cells leads to apoptosis, observed by AO/EBr staining and flow cytometry analysis. The highest pyrimidine-2(5H)-thione internalization in MCF-7 cells may be due to folate conjugated on the surface of curdlan gum nanoparticles. Further, internalized pyrimidine-2(5H)-thione increases the intracellular ROS level, leading to apoptosis and inducing the decalin in mitochondrial membrane potential. These outcomes demonstrated that the FA-Py-CG-PEGamine NPs were specificity-targeting folate receptors on the plasma membranes of MCF-7 Cells. [Display omitted] • Folate receptor encapsulated curdlan gum-PEGamine nanoparticles were fabricated. • Curdlan gum nanoparticles easy to modify their surface through ligands folic acid • Curdlan gum NPs potentially delivered into MCF-7 cancer cells via folate receptor. • The fabricated FA-Py-CG-PEGamine NPs showed improved anticancer activity. [ABSTRACT FROM AUTHOR]

In the present study, the synergetic gelation of curdlan gum (CG) and gellan gum (CG) at different biopolymer ratios were investigated. The optimal gelation of CG and GG was determined at total biopolymer concentration of 0.6% and a mass ratio of 1:1 according to visual observation and viscoelastic properties. The gelation behavior of the CG/GG binary composite gel exhibited ratio-dependent behavior at different biopolymer mixing ratios (2:8–8:2). With the increase in the CG/GG ratio from 2:8 to 8:2, the gel strength and transition temperature of the CG/GG gel showed an increasing trend followed by a decrease, reaching a peak at 5:5, with corresponding G′ , melting and gelling temperatures of 335.8 Pa, 82.5 °C and 33.7 °C, respectively. The improved gel properties could be ascribed to hydrogen bonds between CG and GG, as reflected by the blueshift of the O–H vibration peaks and water associated regional variation. Moreover, the CG/GG binary composite gel exhibited a significantly increasing water holding capacity (WHC) as the ratio of CG/GG decreased from 8:2 to 4:6, while the excess involvement of GG had no effect on the WHC improvement. Furthermore, the CG/GG binary composite gel exhibited denser and more homogeneous microstructures in comparison to individual CG and GG and performed the most compact gel network at ratio of 5:5, supporting the stronger gel rigidity and WHC. Therefore, these novel CG/GG hydrogels showed considerable gel strength and microstructures, which would provide a better mechanistic understanding of the polysaccharide complex in practical applications as a hydrogel base material. [Display omitted] • The addition ratio between CG and GG exhibited a significant effect on the synergy. • CG/GG binary composite gels exhibited good water holding capacity. • The CG/GG binary composite gels mainly driven by hydrogen bonding forces. • The CG/GG binary composite gels exhibited dense and homogeneous microstructures. [ABSTRACT FROM AUTHOR]

The integration of healthy unsaturated fat into plant-based meat alternatives is being advocated worldwide but remains technically challenging, due to limitations in the textural qualities and processability of edible oil. One way to improve the rheological behaviour of oil is via emulsion gel technology. However, adaptable solutions for real-life food processing are few and far between. On this basis, we formulated physically stable emulsion gel hybrid templates with 50–83% sunflower oil load, mostly oil-in-water microstructure, and structured solely by natural food fibres without using oleogelators. The fibres included citrus fibre and soy polysaccharides as emulsifying fibres, and curdlan and deacetylated konjac glucomannan as structuring fibres. Upon heating, they developed stiffness up to 10E4 Pa in storage modulus G′. Here, we present the first characterisation of such fibre-based emulsion gel hybrids through analysis by epifluorescence microscopy, oscillatory rheology, and diffusing wave spectroscopy, and report underlying composition-structure-rheology-thermal behaviour relations. The key findings are that strength in the emulsion gel hybrid could come from combinations of the following observed mechanisms: (i) tiny droplets of dispersed phase droplets with high curvature, (ii) emulsifying fibre of high molecular weight, (iii) controlled interference from emulsifying fibre on the viscoelastic network development of structuring fibre, and (iv) for additional shear stability, highly aggregated state of dispersed phase droplets without coalescence. Promising templates bearing close resemblance to animal fat references such as pork belly fat (in terms of G′), and shear stability with potential toward extrusion and food printing application have been identified. [Display omitted] • Diffusing wave spectroscopy unveiled rheological traits in microstructure phases. • Dispersed oil droplets at ∼10 μm had high complex modulus (103−4 Pa at 101−3 Hz). • Citrus fibre size influenced viscoelastic network development in aqueous phase. • Citrus fibre size influenced thermal stability of dispersed lipid phase. • Highly clustered lipid droplets emulsified by citrus fibre led to shear stability. [ABSTRACT FROM AUTHOR]

Curdlan gum is a neutral water-insoluble bacterial exopolysaccharide composed primarily of linear β-(1,3) glycosidic linkages. Recently, there has been increasing interest in the applications of curdlan and its derivatives. Curdlan is found to inhibit tumors and its sulfated derivative possess anti-HIV activity. Curdlan is biodegradable, non-toxic towards human, environment and edible which makes it suitable as drug-delivery vehicles for sustained drug release. The increasing demand for the growing applications of curdlan requires an efficient high yield fermentation production process so as to satisfy the industrial needs. In this perspective, the present work is aimed to screen and isolate an efficient curdlan gum producing bacteria from rhizosphere of ground nut plant using aniline-blue agar. High yielding isolate was selected based on curdlan yield and identified as Bacillus cereus using gas-chromatography fatty acid methyl ester analysis. B. cereus PR3 curdlan gum was characterized using FT-IR spectroscopy, SEM, XRD and TGA. Fermentation time for curdlan production using B. cereus PR3 was optimized. Media constituents like carbon, nitrogen and mineral sources were screened using Plackett-Burman design. Subsequent statistical analysis revealed that Starch, NH4NO3, K2HPO4, Na2SO4, KH2SO4 and CaCl2 were significant media constituents and these concentrations were optimized for enhancement of curdlan production up to 20.88 g/l. [ABSTRACT FROM AUTHOR]

Non-extrusion texturization technology is essential to broaden the application of alternative proteins to advance sustainability and address the challenges of climate change. We propose a gelation technique to texturize non/low-gelling plant protein using curdlan gum, and to manipulate the gel texture by controlling thermal history. Pea protein and curdlan gum can form soft gel at 55–60 °C, but will form rigid gel at 80 °C. Isothermal incubation for up to 1 h could further develop the gel network with significantly higher storage modulus (e.g. 1.3 kPa without incubation, 288 kPa with 1-h incubation at 80 °C). Although curdlan-pea protein gels formed at 55–60 and 80 °C showed similar modulus ranges after 1-h incubation, the microstructure is noticeably different under microscopes (optical, CLSM, SEM). At 60 °C, large pea protein particles are still visible and only partially embedded into the curdlan network; at 80 °C, smaller protein particles are fully embedded into the gel network. When protein concentration increased from 4% to 8% w/w, the gel network became less organised as more space was occupied by protein particles. We demonstrated that heterogenous structures could be achieved by controlling the thermal history of curdlan-pea protein gels to mimic animal tissue with different stiffness (modulus) between the layers. This gelation technique can potentially be applied to other plant-sourced or alternative proteins without the need of an extruder. [Display omitted] • Curdlan gum forms composite gel with pea protein. • Pea protein particles fully merge into the gel network at 80 °C. • Gel strength modulated by thermal history to produce heterogenous texture. [ABSTRACT FROM AUTHOR]

Paenibacillus polymyxa ATCC 21830 was used for the production of curdlan gum for first time. A Box–Behnken experimental design was applied to optimize six variables of batch fermentation culture each at three levels. Statistical analyses were employed to investigate the direct and interactive effects of variables on curdlan production. Optimum cultural conditions were temperature (50 °C), pH (7), fermentation time (96 h), glucose (100 g/L), yeast extract (3 g/L) and agitation speed (150 rpm). The yield of curdlan production was 6.89 g/L at optimum condition medium. Response surface methodology (RSM) and artificial neural network (ANN) were used to model cultural conditions of curdlan production. The maximum yield of curdlan production were predicted to be 6.68 and 6.85 g/L by RSM and ANN at optimum condition. The prediction capabilities of RSM and ANN were then statistically compared. The results showed that the ANN model is much more accurate in prediction as compared to the RSM. The infrared (IR) and NMR spectra, the thermogram of DSC and pattern of X-ray diffraction for the curdlan of the present study were almost identical to those of the commercial curdlan sample. The average molecular weight of the purified curdlan was determined to be 170 kDa by gel permeation chromatography. [ABSTRACT FROM AUTHOR]

Abstract: The present study was undertaken to investigate the possibility of using date palm juice byproducts for curdlan production by Rhizobium radiobacter ATCC 6466™ in batch experiments. A number of operational parameters, namely pH value, temperature range, inoculum ratio, agitation speed, carbon concentration, nitrogen source, and fermentation time, were investigated in terms of their optimal values for as well as individual and synergistic effects on curdlan production. The findings indicated that the strain exhibited a high ability to use the natural substrate under investigation. A curdlan production yield of 22.83 g/l was obtained in 500-ml agitated flasks (50 ml) when the strain was cultivated in the optimal medium (pH, 7; ammonium sulphate concentration, 2 g/l; date glucose juice concentration, 120 g/l) operating at 30 °C with an inoculum ratio of 5 ml/100 ml, an agitation speed of 180 rpm, and a fermentation period of 51 h. The purified date byproducts-curdlan (DBP-curdlan) had a molecular weight of 180 kDa, a linear structure composed exclusively of β-(1,3)-glucosidic linkages, a melting temperature (T m) and glass transition temperature (T g) of 1.24 and −3.55 °C, respectively. The average measured heights of its molecules were noted to fluctuate between 14.1 ± 0.07 and 211.73 ± 0.6 μm. [ABSTRACT FROM AUTHOR]