Purification, characterization and bioactivity of exopolysaccharides produced by Lactobacillus plantarum KX041

Structural characteristics, immune-activating mechanisms in vitro, and immunomodulatory effects in vivo of the exopolysaccharide EPS53 from Streptococcus thermophilus XJ53

Our previous investigations have successfully identified the repeating structural units of EPS53, an exopolysaccharide derived from Streptococcus thermophilus XJ53 fermented milk, and substantiated its potential immunomodulatory properties. The present study further elucidated the structural characteristics of EPS53 and investigated the underlying mechanisms governing its in vitro immunoreactivity as well as its in vivo immunoreactivity. The results obtained from multi-detector high performance gel filtration chromatography revealed that EPS53 adopted a rigid rod conformation in aqueous solution, with the weight-average molecular weight of 1464 kDa, the number-average molecular weight of 694 kDa, and the polydispersity index of 2.11. Congo red experiment confirmed the absence of a triple helix conformation. Scanning electron microscopy showed that EPS53 displayed a three-dimensional fibrous structure covered with flakes. The in vitro findings indicated that EPS53 enhanced phagocytosis ability, reactive oxygen species (ROS) production, and cytokine levels of macrophages via the TLR4-mediated NF-κB/MAPK signaling pathways as confirmed by immunofluorescence staining experiments, inhibition blocking experiments, and Western blot assay. Additionally, the in vivo experiments demonstrated that EPS53 significantly increased macrophage and neutrophil number while enhancing NO and ROS levels in zebrafish larvae; thus, providing further evidence for the immunomodulatory efficacy of EPS53.

The carrier function and inhibition effect on benign prostatic hyperplasia of a glucan from Epimedium brevicornu Maxim

Epimedium, a traditional Chinese medicine commonly used as a dietary supplement, contains polysaccharides and flavonoids as its main bioactive ingredients. In this study, a neutral homogeneous polysaccharide (EPSN-1) was isolated from Epimedium brevicornu Maxim. EPSN-1 was identified as a glucan with a backbone of →4)-α-D-Glcp-(1→, branched units comprised α-D-Glcp-(1→6)-α-D-Glcp-(1→, β-D-Glcp-(1→6)-β-D-Glcp-(1→ and α-D-Glcp-(1→ connected to the C6 position of backbone. The conformation of EPSN-1 in aqueous solution indicated its potential to form nanoparticles. This paper aims to investigate the carrier and pharmacodynamic activity of EPSN-1. The findings demonstrated that, on the one hand, EPSN-1, as a functional ingredient, may load Icariin (ICA) through non-covalent interactions, improving its biopharmaceutical properties such as solubility and stability, thereby improving its intestinal absorption. Additionally, as an effective ingredient, EPSN-1 could help maintain the balance of the intestinal environment by increasing the abundance of Parabacteroides, Lachnospiraceae UGG-001, Anaeroplasma, and Eubacterium xylanophilum group, while decreasing the abundance of Allobaculum, Blautia, and Adlercreutzia. Overall, this dual action of EPSN-1 sheds light on the potential applications of natural polysaccharides, highlighting their dual role as carriers and contributors to biological activity.

Bioprospecting of exopolysaccharides from the endophytic fungi Epicoccum sorghinum AMFS4, for its structure, composition, bioactivities and application in seed priming

The endophytic fungi, Epicoccum sorghinum AMFS4 was investigated for its metabolic components and composition of bioactive exopolysaccharides (EPS). Metabolic analysis of the ethyl acetate extract majorly detected sugars derivatives such as, 4-Cholesten-3-one semicarbazone (20.9%), d-Fructose (18.96%), and α-d-Galactopyranosiduronicacid (1.71%). The growth curve and EPS yield were determined as 12.22 ± 1.02 g/L and 7.41 ± 0.32 g/L (dry weight) respectively on day 8. The deproteined EPS has been characterised with pyranose ring linked by α-glycosidic bonds, composing fructose, galactose and glucose monosaccharides validated by HPLC. Total sugar content was found to be 93.18 ± 0.81% with detection of proteins and uronate. The viscous EPS appeared filamentous under SEM observation and behaves as emulsifier with notable antioxidant properties. Priming of EPS on tomato seeds showed early induction of secondary rooting than in the control seedlings. Thus, E. sorghinum AMFS4 synthesises bioactive EPS with simple carbohydrate structure, good water absorption and significant metabolic influence on seed germination.

An Exploration of the Antioxidative and Anti-Inflammatory Role of Lactiplantibacillus plantarum 106 via Improving Mitochondrial Function

In this present study, bioinformatics analysis and the experimental validation method were used to systematically explore the antioxidant activity and anti-inflammatory effect of Lactiplantibacillus plantarum A106, which was isolated from traditional Chinese pickles, on lipopolysaccharide (LPS)-induced RAW264.7 macrophages. L. plantarum A106 had a good scavenging ability for DPPH, ABTS, and hydroxyl radicals. Furthermore, L. plantarum A106 could increase the activity of RAW264.7 macrophages; raise the SOD and GSH levels, with or without LPS sensitization; or decrease the MDA, TNF-α, and IL-6 levels. In order to deeply seek the antioxidant and anti-inflammatory role and mechanism, bioinformatic analysis, including GO, KEGG, and GSEA analysis, was used to conduct an in-depth analysis, and the results showed that the LPS treatment of RAW264.7 macrophages significantly upregulated inflammatory-related genes and revealed an enrichment in the inflammatory signaling pathways. Additionally, a network analysis via the Cytoscape software (version 3.9.1) identified key central genes and found that LPS also disturbed apoptosis and mitochondrial function. Based on the above bioinformatics analysis, the effects of L. plantarum A106 on inflammation-related gene expression, mitochondrial function, apoptosis, etc., were detected. The results indicated that L. plantarum A106 restored the declined expression levels of crucial genes like TNF-α and IL-6; mitochondrial membrane potential; and apoptosis and the expression of apoptosis-related genes, Bcl-2, Caspase-3, and Bax. These results suggest that L. plantarum A106 exerts antioxidant activity and anti-inflammatory effects through regulating inflammatory and apoptosis-related gene expression, restoring the mitochondrial membrane potential.

Improving the Antioxidant and Anti-Inflammatory Activity of Fermented Milks with Exopolysaccharides-Producing Lactiplantibacillus plantarum Strains

Exopolysaccharides (EPSs) producing lactic acid bacteria have been claimed to confer various health benefits to the host, including the ability to face oxidative and inflammatory-related stress. This study investigated the ability of food-borne Lactiplantibacillus (Lpb.) plantarum to improve the antioxidant activity of fermented milks by producing EPSs. Two Lpb. plantarum strains, selected as lower and higher EPSs producers, have been applied in lab-scale fermented milk production, in combination with conventional starters. Antioxidant activity was investigated in vitro using DPPH (1,1-diphenyl-2-picrylhydrazyl), ABTS (2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and FRAP (ferric reducing antioxidant power) assays while the ability to modulate reactive oxygen species (ROS) level was evaluated in an intestinal healthy model, subjected to both oxidative and inflammatory stress. Furthermore, to verify whether digestion affects functionality, fermented milks were evaluated before and after in vitro-simulated INFOGEST digestion. The results showed an improved antioxidant activity of fermented milk enriched with Lpb. plantarum LT100, the highest EPSs producer. Furthermore, the data showed a different ROS modulation with a protective anti-inflammatory effect of samples enriched with Lpb. plantarum strains. Our data suggest the use of selected EPS-producing strains of Lpb. plantarum as a natural strategy to enrich the functionality of fermented milks in terms of ROS modulation and inflammatory-related stress.

Guardians of the Gut: Harnessing the Power of Probiotic Microbiota and Their Exopolysaccharides to Mitigate Heavy Metal Toxicity in Human for Better Health

Heavy metal pollution is a significant global health concern, posing risks to both the environment and human health. Exposure to heavy metals happens through various channels like contaminated water, food, air, and workplaces, resulting in severe health implications. Heavy metals also disrupt the gut's microbial balance, leading to dysbiosis characterized by a decrease in beneficial microorganisms and proliferation in harmful ones, ultimately exacerbating health problems. Probiotic microorganisms have demonstrated their ability to adsorb and sequester heavy metals, while their exopolysaccharides (EPS) exhibit chelating properties, aiding in mitigating heavy metal toxicity. These beneficial microorganisms aid in restoring gut integrity through processes like biosorption, bioaccumulation, and biotransformation of heavy metals. Incorporating probiotic strains with high affinity for heavy metals into functional foods and supplements presents a practical approach to mitigating heavy metal toxicity while enhancing gut health. Utilizing probiotic microbiota and their exopolysaccharides to address heavy metal toxicity offers a novel method for improving human health through modulation of the gut microbiome. By combining probiotics and exopolysaccharides, a distinctive strategy emerges for mitigating heavy metal toxicity, highlighting promising avenues for therapeutic interventions and health improvements. Further exploration in this domain could lead to groundbreaking therapies and preventive measures, underscoring probiotic microbiota and exopolysaccharides as natural and environmentally friendly solutions to heavy metal toxicity. This, in turn, could enhance public health by safeguarding the gut from environmental contaminants.

Efficacy of exopolysaccharide in dye-laden wastewater treatment: A comprehensive review

The discharge of dye-laden wastewater into the water streams causes severe water and soil pollution, which poses a global threat to aquatic ecosystems and humans. A diverse array of microorganisms such as bacteria, fungi, and algae produce exopolysaccharides (EPS) of different compositions and exhibit great bioflocculation potency to sustainably eradicate dyes from water bodies. Nanomodified chemical composites of EPS enable their recyclability during dye-laden wastewater treatment. Nevertheless, the selection of potent EPS-producing strains and physiological parameters of microbial growth and the remediation process could influence the removal efficiency of EPS. This review will intrinsically discuss the fundamental importance of EPS from diverse microbial origins and their nanomodified chemical composites, the mechanisms in EPS-mediated bioremediation of dyes, and the parametric influences on EPS-mediated dye removal through sorption/bioflocculation. This review will pave the way for designing and adopting futuristic green and sustainable EPS-based bioremediation strategies for dye-laden wastewater in situ and ex situ.

Structure and Properties of Exopolysaccharide Produced by Gluconobacter frateurii and Its Potential Applications

An exopolysaccharide (EPS)-producing bacterium was isolated from apricot fermentation broth and identified as Gluconobacter frateurii HDC-08 (accession number: OK036475.1). HDC-08 EPS is a linear homopolysaccharide mainly composed of glucose linked by α-(1,6) glucoside bonds. It contains C, H, N and S elements, with a molecular weight of 4.774 × 106 Da. Microscopically, it has a smooth, glossy and compact sheet structure. It is an amorphous noncrystalline substance with irregular coils. Moreover, the EPS showed surface hydrophobicity and high thermal stability with a degradation temperature of 250.76 °C. In addition, it had strong antioxidant properties against DPPH radicals, ABPS radicals, hydroxyl radicals and H2O2. The EPS exhibited high metal-chelating activity and strong emulsifying ability for soybean oil, petroleum ether and diesel oil. The milk solidification test indicated that the EPS had good potential in fermented dairy products. In general, all the results demonstrate that HDC-08 EPS has promise for commercial applications as a food additive and antioxidant.

Structures, physical properties and antibacterial activity of silver nanoparticles of Lactiplantibacillus plantarum exopolysaccharide

Lactic acid bacteria (LAB) exopolysaccharide (EPS) has good water absorption, high viscosity, good stability, so it was widely used in probiotics fields. In this study, EPS-producing LAB strain Lactiplantibacillus plantarum HDL-03 was isolated and identified. Moreover, the HDL-03 EPS was used as a stabilizer and mixed with AgNO3 to synthesize a novel nanoparticle AgNPs whose structure and properties were explored. The monosaccharide composition and molecular weight indicated that HDL-03 EPS was a heteropolysaccharide composed of mannose and glucose. Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) spectroscopy analysis and methylation results jointly proved it was a heteropolysaccharide containing 1,3-Manp and 1,6-Glcp. The X-Ray diffraction (XRD) results showed that this EPS has an amorphous structure, while the synthesized AgNPs have crystalline properties. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results indicated EPS had a smooth and dense sheet structure, while the surface of AgNPs became rougher and large holes appeared after synthesis. Zeta particle size analysis suggested that the particle size of AgNPs increased by 36.63 nm compared to HDL-03 EPS. FT-IR analysis exhibited that the position of the characteristic peaks of AgNPs changed. The OH moving from a wavelength of 3388.49 cm-1 to a wavelength of 3316.79 cm-1 and telescopic vibration peak changed from 1356.07 cm-1 to 1344.22 cm-1. A plate inhibition test revealed the effect of different concentrations of EPS and AgNO3 synthesized AgNPs on the diameter of inhibition circle produced by the indicator bacteria Escherichia coli and Staphylococcus aureus. Furthermore, AgNPs were applied to the indicator bacteria, which the minimum inhibitory concentration (MIC), time-inhibitory curve, and changes in extracellular conductivity, nucleic acids, proteins, ATP, and lactate dehydrogenase (LDH) levels were determined. The AgNPs inhibited the growth of E. coli and S. aureus and exhibited outstanding antimicrobial properties. With the increase of treatment time, the degree of cell membrane damage increased, the permeability enhanced, and the intracellular substances leaked. These results indicate that HDL-03 EPS has good potential for applications in the production of food packaging, antimicrobials, catheters, textiles and coatings.

Research progress on the functions, preparation and detection methods of l-fucose

l-fucose is a six-carbon sugar that has potential applications in many fields. It exerts antitumor effects and could relieve intestinal disease. It exhibits potential as an emulsifier in the food industry. It is also used as a functional food and in anti-aging skincare products. However, at present, it is not possible to prepare high-purity l-fucose on a large scale, and its preparation needs further development. This review summarizes the preparation methods of l-fucose including chemical synthesis, enzymatic synthesis, microbial fermentation, and separation and purification from algae. The detection methods of l-fucose are also introduced in detail, such as l-fucose-specific lectin, detection l-fucose dehydrogenase, cysteine-sulfuric acid method, high-performance liquid chromatography, gas chromatography, and biosensors. In this review, the properties and pharmacological effects of l-fucose; preparation methods, and the commonly used detection methods of l-fucose are reviewed to serve as a reference material.

Structural and functional characterization of exopolysaccharide from Leuconostoc citreum BH10 discovered in birch sap

In this study, Leuconostoc citreum BH10, an endophytic strain, was isolated from aseptically collected xylem sap of birch for the first time, and its exopolysaccharide (LCEPS) production was up to 46.31 g/L in glucan producing medium. The produced LCEPS was purified to obtain two water-soluble fractions, named as LCEPS-1 and LCEPS-2, respectively. The major fraction LCEPS-1 was characterized to be comprised of glucose with average molecular weight of 6.34 × 106 Da. The structure of LCEPS-1 was investigated by spectroscopy analysis, which revealed that LCEPS-1 was identified with containing 90.45 % α-(1,6) linkages in the main chains and 9.55 % α-(1,3) branch linkages. The scanning electron microscope results demonstrated that the dried LCEPS-1 appeared porous surface overlaid with an irregular glittering. The water solubility index (WSI) and water holding capacity (WHC) of LCEPS-1 were 88.02 ± 1.69 % and 241.43 ± 6.38 %, respectively. Besides, it exhibited high thermal stability as well as fine antioxidant activities. Taken together, the results indicated that LCEPS-1 could have good potentiality to be applied in fields of foods, cosmetics, nutraceuticals and pharmaceutical industries as the natural agent.

Structural Characterization and Immunomodulatory Activity of a Mannose-Rich Polysaccharide Isolated from Bifidobacterium breve H4-2

In this study, a novel homogeneous mannose-rich polysaccharide named EPS-1 from the fermentation broth of Bifidobacterium breve H4-2 was isolated and purified by anion exchange column chromatography and gel column chromatography. The primary structure of EPS-1 was analyzed by high-performance liquid chromatography, Fourier-transform infrared spectroscopy, gas chromatography-mass spectrometry, and nuclear magnetic resonance. The results indicated that EPS-1 had typical functional groups of polysaccharides. EPS-1 with an average molecular weight of 3.99 × 104 Da was mainly composed of mannose (89.65%) and glucose (5.84%). The backbone of EPS-1 was →2,6)-α-d-Manp-(1→2)-α-d-Manp-(1→2,6)-α-d-Manp-(1→2)-α-d-Manp-(1→2,6)-α-d-Manp-(1→6)-α-d-Glcp-(1→ simultaneously containing two kinds of branched chains (α-d-Manp-(1→3)-α-d-Manp-(1→ and α-d-Manp-(1→). Besides, EPS-1 had a triple-helical conformation and exhibited excellent thermal stability. Moreover, the immunomodulatory activity of EPS-1 was evaluated by RAW 264.7 cells. Results indicated that EPS-1 significantly enhanced the viability of RAW 264.7 cells. EPS-1 could also be recognized by toll-like receptor 4, thereby activating the nuclear factors-κB (NF-κB) signaling pathway, promoting phosphorylation of related nuclear transcription factors, improving cell phagocytic activity, and promoting the secretion of NO, IL-6, IL-1β, and TNF-α. Thus, EPS-1 could activate the TLR4-NF-κB signaling pathway to emerge immunomodulatory activity on macrophages. The above results indicate that EPS-1 can serve as a potential immune-stimulating polysaccharide.

Gene Expression, Structural Characterization, and Functional Properties of Exopolysaccharide Produced from Potential Probiotic Enterococcus faecalis NOC219 Strain

This study aimed to reveal the structural characterization and functional properties of microbial EPS-NOC219 material produced by the Enterococcus faecalis NOC219 strain with high EPS yield isolated from yogurt, with simultaneously, demonstrating the potential of this EPS for future industrial applications. According to the results of the analyses made for this aim, it was determined that the NOC219 strain contains the epsB, p-gtf-epsEFG, and p-gtf-P1 genes. In addition, it was also revealed that the EPS-NOC219 structure is expressed by the epsB, p-gtf-epsEFG, and p-gtf-P1 genes and has a heteropolymeric feature consisting of glucose, galactose, and fructose units. According to the results of the analyses made for this aim, it was determined that the EPS-NOC219 structure, which was produced from the NOC219 strain containing the epsB, p-gtf-epsEFG, and p-gtf-P1 genes, had a heteropolymeric structure consisting of glucose, galactose, and fructose units. On the other hand, it was shown that this structure had a thickener property, high heat stability exhibited a pseudoplastic flow behavior, and had a high melting point. This showed that the EPS-NOC219 had high heat stability and could be used as a thickener in heat treatment processes. In addition, it was revealed that it is suitable for plasticized biofilm production. On the other hand, the bioavailability of this structure was demonstrated with its high antioxidant activity (55.84%) against DPPH radicals and high antibiofilm activity against Escherichia coli (77.83%) and Listeria monocytogenes (72.14%) pathogens. These results suggest that the EPS-NOC219 structure may be an alternative natural resource for many industries as it has strong physicochemical properties and a healthy food-grade adjunct.

Characterization and bioactivities of exopolysaccharide produced from Azotobacter salinestris EPS-AZ-6

This study involved the extraction of an exopolysaccharide (EPS) from Azotobacter salinestris AZ-6, which was isolated from soil cultivated with leguminous plants. In a medium devoid of nitrogen, the AZ-6 strain displayed a maximum EPS yield of 1.1 g/l and the highest relative viscosity value of 3.4. The homogeneity of the polymer was demonstrated by the average molecular weight of 1.61 × 106 Da and a retention time of 17.211 min for levan. The presence of characteristic functional groups and structural units of carbohydrate polymers has been confirmed through spectroscopic analyses utilizing Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) techniques. Thermogravimetric analysis (TGA) revealed a noteworthy decrease in weight (74 %) in the temperature range spanning from 260 to 350 °C. X-ray diffraction (XRD) was utilized to verify the crystalline and amorphous characteristics of EPS-AZ-6. The EPS-AZ-6 exhibited significant cytotoxicity against the MCF-7 tumor cell line, as evidenced by an IC50 value of 6.39 ± 0.05 μg/ml. It also demonstrated a moderate degree of cytotoxicity towards HepG-2 cell line, as indicated by an IC50 value of 29.79 ± 0.41 μg/ml. EPS-AZ-6 exhibited potent antioxidant and in vitro antibacterial properties. These characteristics suggest the potential application value of EPS-AZ-6 in the food industry and pharmaceutical applications.

GAPDH Released from Lactobacillus johnsonii MG Enhances Barrier Function by Upregulating Genes Associated with Tight Junctions

Extracellular glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has multiple interactions with various gut epithelial components. For instance, GAPDH in Lactobacillus johnsonii MG cells interacts with junctional adhesion molecule-2 (JAM-2) in Caco-2 cells and enhances tight junctions. However, the specificity of GAPDH toward JAM-2 and its role in the tight junctions in Caco-2 cells remain unclear. In the present study, we assessed the effect of GAPDH on tight junction regeneration and explored the GAPDH peptide fragments required for interaction with JAM-2. GAPDH was specifically bound to JAM-2 and rescued H₂O₂-damaged tight junctions in Caco-2 cells, with various genes being upregulated in the tight junctions. To understand the specific amino acid sequence of GAPDH that interacts with JAM-2, peptides interacting with JAM-2 and L. johnsonii MG cells were purified using HPLC and predicted using TOF-MS analysis. Two peptides, namely ¹¹GRIGRLAF¹⁸ at the N-terminus and ³²³SFTCQMVRTLLKFATL³³⁸ at the C-terminus, displayed good interactions and docking with JAM-2. In contrast, the long peptide ⁵²DSTHGTFNHEVSATDDSIVVDGKKYRVYAEPQAQNIPW⁸⁹ was predicted to bind to the bacterial cell surface. Overall, we revealed a novel role of GAPDH purified from L. johnsonii MG in promoting the regeneration of damaged tight junctions and identified the specific sequences of GAPDH involved in JAM-2 binding and MG cell interaction.

Extraction and characterization of exopolysaccharides from Lactiplantibacillus plantarum strain PRK7 and PRK 11, and evaluation of their antioxidant, emulsion, and antibiofilm activities

Exopolysaccharides (EPS) are produced by probiotic bacteria Lactiplantibacillus plantarum PRK7 and L. plantarum PRK11. The structure of EPS-7 and EPS-11 was characterized by Fourier-transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), gas chromatography-mass spectroscopy (GCMS), and thermogravimetric analysis (TGA). Further, in in vitro studies antioxidant, emulsion, and antibiofilm activity were investigated. The FTIR spectrum confirmed the presence of polysaccharides in EPS-7 and EPS-11, with absorbance at 1654.93 and 1655.33 cm^-1, respectively. H¹ NMR further confirmed the presence of glucose, galactose, xylose, and mannose. Sugar derivatives in EPS-7 and EPS-11 were further confirmed with GCMS. The SEM analysis revealed that EPS-7 had a weblike structure and EPS-11 had a smooth porous layer. The result of the TGA revealed that EPS-7 and EPS-11 had greater thermal stability at 319.1 and 300.1 °C, respectively. Furthermore, EPS-7 and EPS-11 showed a good percentage of free radical scavenging in DPPH (89.77 % and 93.1 %), ABTS (57.65 % and 58.63 %), hydroxyl radical scavenging (44.46 % and 40.308 %), and reducing power assay. The emulsion activity was confirmed with edible oils such as coconut oil, sesame oil, almond oil, castor oil, and neem oil. The highest emulsion activity for EPS-7 and EPS-11 was found be with coconut and castor oil. In addition, the antibiofilm activity against pathogens revealed that EPS possess can prevent biofilm formation. Thus, it was found that EPS-7 and EPS-11 possess good structural characteristics and their biological activity makes them ideal for applications in the food and pharmaceutical industry.

Structural characterization, α-glucosidase inhibitory activity and antioxidant activity of neutral polysaccharide from apricot (Armeniaca Sibirica L. Lam) kernels

Screening for α-glucosidase inhibitors and antioxidants from natural sources that could reduce postprandial glucose in diabetic patients and reduce oxidative stress had attracted considerable interest. In this study, a neutral polysaccharide (AP-1) with a triple helix structure was isolated and purified from the residue of apricot (Armeniaca sibirica L. Lam.) kernels by using DEAE-52 and Sephadex G-100 columns. The molecular weight of AP-1 was 23.408 kDa and consisted mainly of glucose with trace amounts of arabinose, galactose, and mannose, which had molar percentages of 98.48, 0.63, 0.62 and 0.27 %, respectively. The main chain of AP-1 was composed of →4)-α-D-Glcp-(1 → interlinked, and α-D-Glcp-(1 → was attached as a branched chain at the O-6 position of →4,6)-α-D-Glcp-(1→. In addition, AP-1 exhibited stronger α-glucosidase inhibition and free radical scavenging ability compared to crude polysaccharides. Therefore, AP-1 could be used as a potential natural hypoglycemic agent and antioxidant in the treatment of diabetes mellitus.

The Profile of Exopolysaccharides Produced by Various Lactobacillus Species from Silage during Not-Fat Milk Fermentation

The exopolysaccharides (EPS) produced by lactic acid bacteria (LAB) and released into fermented milk play a protective role from stress factors as well as improve emulsifying and thickening properties of the product, reduce syneresis, and increase elasticity. Here we report the relationship between the properties, composition, and microstructure of EPS produced by six different strains of lactobacilli (L. bulgaricus and five strains isolated from silage). The presence of fructose together with negative-charged uronic acid was found to play a significant role in changing the EPS properties. Thus, the increased fraction of rhamnose and arabinose and a decrease in xylose leads to compaction of the EPS, decreased porosity and increased both OH- and superoxide scavenging and Fe-chelating activities. By contrast, increased xylose and low rhamnose and arabinose apparently leads to loss of large aggregates and high DPPH activity and FRAP. The high content of glucose, however, provides the formation of large pores. The increased fructan fraction (69.9 mol%) with a high fraction of galacturonic (18.2 mol%) and glucuronic acids (6.7 mol%) apparently determines the highly porous spongy-folded EPS microstructure. Taken together, our results indicate that both the quantitative characteristics of the individual components of the fraction and the structural features of EPS are important for the antioxidant potential of fermented milk and depend on the strain used for milk fermentation, suggesting the advantage of a multicomponent starter to achieve the optimal beneficial properties of fermented milk.

Optimization and cholesterol-lowering activity of exopolysaccharide from Lactiplantibacillus paraplantarum NCCP 962

Exopolysaccharides (EPSs) are biological polymers with unique structural features have gained particular interest in the fields of food, chemistry and medicine, and food industry. EPS from the food-grade lactic acid bacteria (LAB) can be used as a natural food additives to commercial ones in the processing and development of functional foods and nutraceuticals. The current study was aimed to explore the EPS-producing LAB from the dahi; to optimize the fermentation conditions through Plackett-Burman (PB) and response surface methodology (RSM); and to study its physicochemical, rheological, functional attributes, and cholesterol-lowering activity. Lactiplantibacillus paraplantarum NCCP 962 was isolated among the 08 strains screened at the initial stage. The PB design screened out four independent factors that had a significant positive effect, i.e., lactose, yeast extract, CaCl₂, and tryptone, while the remaining seven had a non-significant effect. The RSM exhibited lactose, yeast extract, and CaCl_2, significantly contributing to EPS yield. The maximum EPS yield (0.910 g/L) was obtained at 6.57% lactose, 0.047% yeast extract, 0.59% CaCl_2, and 1.37% tryptone. The R² value above 97% explains the higher variability and depicts the model's validity. The resulted EPS was a heteropolysaccharide in nature with mannose, glucose, and galactose monosaccharides. FTIR spectrum reflected the presence of functional groups, i.e., O-H, C-H, C = O, C-O-H, and CH₂. SEM revealed a porous and rough morphology of EPS, also found to be thermally stable and negligible weight loss, i.e., 14.0% at 257 °C and 35.4% at 292.9 °C was observed in the 1st and 2nd phases, respectively. Rheological attributes revealed that strain NCCP 962 had high viscosity by increasing the EPS concentration, low pH, and temperature with respectable water holding, oil capacities, foaming abilities, and stability. NCCP 962 EPS possessed up to 46.4% reduction in cholesterol concentration in the supernatant. Conclusively, these results suggested that strain NCCP 962 can be used in food processing applications and other medical fields. KEY POINTS: • The fermentation conditions affect EPS yield from L. paraplantarum and significantly increased yield to 0.910 g/L. • The EPS was heteropolysaccharide in nature and thermally stable with amorphous morphology. • Good cholesterol-lowering potential with the best rheological, emulsifying, and foaming capacities.

Exopolysaccharides from lactic acid bacteria, as an alternative to antibiotics, on regulation of intestinal health and the immune system

Over-use or misuse of antibiotics in livestock and poultry production contributes to the rising threat of antibiotic resistance in animals and has negative ecological effects. Exopolysaccharides from lactic acid bacteria (LAB-EPS) are a class of biological macromolecules which are secreted by lactic acid bacteria to the outside of the cell wall during their growth and metabolism. Numerous studies demonstrated that LAB-EPS have anti-inflammatory and antimicrobial activities and are able to regulate intestinal health and the immune system in livestock. They are biodegradable, nontoxic and bio-compatible, which are considered as ideal alternatives to antibiotics. This review aims to discuss and summarize recent research findings of LAB-EPS on regulation of intestinal health and the immune system in animals, and thus provide scientific justification for commercial applications of LAB-EPS in livestock.

Utilization of exopolysaccharide produced by Leuconostoc lactis GW-6 as an emulsifier for low-fat mayonnaise production

This study aimed to investigate the potential usage of exopolysaccharide (EPS) produced by Leuconostoc lactis GW-6 species as an emulsifier in a low-fat mayonnaise by the formation of a complex with whey protein isolate (WPI) to improve rheological properties, emulsion, and oxidative stability. For the determination of rheological properties, the flow behavior, frequency sweep, and 3-ITT rheological properties of low-fat mayonnaise samples were studied. All samples showed shear thinning, viscoelastic solid-like, and recoverable character. The K and n values for the mayonnaise samples were determined as 24.529-174.403 Pa.sⁿ and 0.166-0.304, respectively, indicating that shear-thinning characters could be improved with WPI-EPS interaction. The higher K' and K″ values of all low-fat samples prepared with EPS-WPI than the low-fat control sample explained the synergistic effect of EPS and WPI. Importantly, no effect was observed when WPI was used as alone as an emulsifier. Oxidative stability was tested by OXITEST and IP values of samples prepared by WPI and EPS were compared to control samples. In conclusion, the results of this study showed that the EPS and WPI interaction can significantly affect the rheological properties and emulsion and oxidative stability of mayonnaise samples.

Characterization of Dextran Biosynthesized by Glucansucrase from Leuconostoc pseudomesenteroides and Their Potential Biotechnological Applications

Glucansucrase was purified from Leuconostoc pseudomesenteroides. The glucansucrase exhibited maximum activity at pH 5.5 and 30 °C. Ca²⁺ significantly promoted enzyme activity. An exopolysaccharide (EPS) was synthesized by this glucansucrase in vitro and purified. The molecular weight of the EPS was 3.083 × 10⁶ Da. Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy showed that the main structure of glucan was 97.3% α-(1→6)-linked D-glucopyranose units, and α-(1→3) branched chain accounted for 2.7%. Scanning electron microscopy (SEM) observation of dextran showed that its surface was smooth and flaky. Atomic force microscopy (AFM) of dextran revealed a chain-like microstructure with many irregular protuberances in aqueous solution. The results showed that dextran had good thermal stability, water holding capacity, water solubility and emulsifying ability (EA), as well as good antioxidant activity; thus it has broad prospects for development in the fields of food, biomedicine, and medicine.

Purification, structural characterization and antioxidant activities of two neutral polysaccharides from persimmon peel

Two neutral polysaccharides (PPP1-1 and PPP1-2) were purified from persimmon peel. PPP1-1 (21.84 kDa) was mainly composed of arabinose (22.92 %), galactose (21.09 %), glucose (35.13 %), and xylose (19.09 %), while PPP1-2 (10.42 kDa) mainly contained arabinose (32.98 %), galactose (20.81 %), glucose (26.86 %), xylose (10.46 %), and mannose (7.63 %). Methylation and NMR spectra analysis demonstrated that the backbone of PPP1-1 appeared to be →6)-α-D-Glcp-(1→, →2,6)-α-D-Glcp-(1→, →5)-α-L-Araf-(1→, and →3,5)-α-L-Araf-(1 → residues with branches consisting of →3)-α-L-Araf-(1→, →4)-α-D-Glcp-(1→, →3)-β-D-Galp-(1→, →4)-β-D-Galp-(1→, →4)-β-D-Xylp-(1→, →6)-β-D-Galp-(1→, →4)-β-D-Manp-(1→, and α-L-Araf-(1 → residues. The main chain of PPP1-2 was composed of →6)-α-D-Glcp-(1→, →5)-α-L-Araf-(1→, and →3,5)-α-L-Araf-(1 → residues with branches consisting of →3)-α-L-Araf-(1→, →1,2)-α-D-Glcp-(6→, →4)-α-D-Glcp-(1→, →3)-β-D-Galp-(1→, →4)-β-D-Galp-(1→, →6)-β-D-Galp-(1→, →4)-β-D-Xylp-(1→, →4,6)-α-D-Glcp-(1→, and →4)-β-D-Manp-(1 → residues and terminal of α-L-Araf-(1 → residue. PPP1-2 exhibited stronger antioxidant activities and better thermal stability than PPP1-1. Our results provided the foundation for further investigating the structure and biological activities of persimmon peel polysaccharides and highlighted their potential to become potential antioxidants in functional food.

Feeding Lactic Acid Bacteria with Different Sugars: Effect on Exopolysaccharides (EPS) Production and Their Molecular Characteristics

Exopolysaccharides (EPS) are complex molecules produced by some microorganisms and used in foods as texturizers and stabilizers, their properties depending on their chemical structure. In this work, three different lactic acid bacteria (LAB), were tested for their ability to produce EPS, by using five different mono- and disaccharides as their sole carbon source. The growth and acidifying ability were analysed, the EPSs were quantified by the official method AOAC 991.43, and their chemical structure was investigated. The amount of EPS varied from 0.71 g/L to 2.38 g/L, and maltose was the best sugar for EPS production by Lacticaseibacillus paracasei 2333. Lacticaseibacillus rhamnosus 1019 produced the highest amount when fed with lactose, whereas the EPS amount of Lactobacillus bulgaricus 1932 was not significantly different depending on the sugar type. The EPS chains consisted of fructose, galactose, glucose, mannose, ribose, glucosamine, galactosamine, and in some cases rhamnose in different proportions, depending on the strain and carbon source. The molecular weight of EPS ranged from <10 KDa to >500 KDa and was again highly dependent on the strain and the sugar used, suggesting the possibility of growing different strains under different conditions to obtain EPS with different potential applications in the food system.

Microbial exopolysaccharides-β-glucans-as promising postbiotic candidates in vaccine adjuvants

The urgent task of creating new, enhanced adjuvants is closely related to our comprehension of their mechanisms of action. A few adjuvants have shown sufficient efficacy and low toxicity to be allowed for use in human vaccines, despite the fact that they have a long history and an important function. Adjuvants have long been used without a clear understanding of how precisely they augment the immune response. The rational production of stronger and safer adjuvants has been impeded by this lack of information, which necessitates more mechanistic research to support the development of vaccines. Carbohydrate structures-polygalactans, fructans, β-D-glucans, α-D-glucans, D-galactose, and D-glucose-are desirable candidates for the creation of vaccine adjuvants and immunomodulators because they serve important functions in nature and are often biocompatible, safe, and well tolerated. In this review, we have discussed recent advances in microbial-derived carbohydrate-based adjuvants, their immunostimulatory activity, and the implications of this for vaccine development, along with the critical view on the microbial sources, chemical composition, and biosynthetic pathways.

Characterization of Novel Exopolysaccharides from Enterococcus hirae WEHI01 and Its Immunomodulatory Activity

Exopolysaccharide (EPS) from probiotic Enterococcus hirae WEHI01 was isolated and purified by anion exchange chromatography and gel chromatography, the results of which show that the EPS consists of four fractions, namely I01-1, I01-2, I01-3, and I01-4. As the main purification components, I01-2 and I01-4 were preliminarily characterized for their structure and their immunomodulatory activity was explored. The molecular weight of I01-2 was 2.28 × 104 Da, which consists mainly of galactose, and a few other sugars including glucose, arabinose, mannose, xylose, fucose, and rhamnose, while the I01-4 was composed of galactose only and has a molecular weight of 2.59 × 104 Da. Furthermore, the results of an evaluation of immunomodulatory activity revealed that I01-2 and I01-4 could improve the viability of macrophage cells, improve phagocytosis, boost NO generation, and encourage the release of cytokines including TNF-α and IL-6 in RAW 264.7 macrophages. These results imply that I01-2 and I01-4 could improve macrophage-mediated immune responses and might be useful in the production of functional food and medications.

Chicken intestinal microbiota modulation of resistance to nephropathogenic infectious bronchitis virus infection through IFN-I

BACKGROUND

Mammalian intestinal microbiomes are necessary for antagonizing systemic viral infections. However, very few studies have identified whether poultry commensal bacteria play a crucial role in protecting against systemic viral infections. Nephropathogenic infectious bronchitis virus (IBV) is a pathogenic coronavirus that causes high morbidity and multiorgan infection tropism in chickens.

RESULTS

In this study, we used broad-spectrum oral antibiotics (ABX) to treat specific pathogen free (SPF) chickens to deplete the microbiota before infection with nephropathogenic IBV to analyze the impact of microbiota on IBV infections in vivo. Depletion of the SPF chicken microbiota increases pathogenicity and viral burden following IBV infection. The gnotobiotic chicken infection model further demonstrated that intestinal microbes are resistant to nephropathogenic IBV infection. In addition, ABX-treated chickens showed a severe reduction in macrophage activation, impaired type I IFN production, and IFN-stimulated gene expression in peripheral blood mononuclear cells and the spleen. Lactobacillus isolated from SPF chickens could restore microbiota-depleted chicken macrophage activation and the IFNAR-dependent type I IFN response to limit IBV infection. Furthermore, exopolysaccharide metabolites of Lactobacillus spp. could induce IFN-β.

CONCLUSIONS

This study revealed the resistance mechanism of SPF chicken intestinal microbiota to nephropathogenic IBV infection, providing new ideas for preventing and controlling nephropathogenic IBV. Video abstract.

Novel exopolysaccharide derived from probiotic Lactobacillus pantheris TCP102 strain with immune-enhancing and anticancer activities

Probiotics are gaining attention due to their functions of regulating the intestinal barrier and promoting human health. The production of exopolysaccharide (EPS) is one of the important factors for probiotics to exert beneficial properties. This study aimed to screen exopolysaccharides-producing lactic acid bacteria (LAB) and evaluate the probiotic potential. we obtained three exopolysaccharide fractions (EPS1, EPS2, and EPS3) from Lactobacillus pantheris TCP102 and purified by a combination of ion-exchange chromatography and gel permeation chromatography. The structures of the fractions were characterized by FT-IR, UV, HPLC, and scanning electron microscopy (SEM) analysis. The Mw of EPS1, EPS2, and EPS3 were approximately 20.3, 23.0, and 19.3 kDa, and were mainly composed of galactose, glucose, and mannose, with approximate molar ratios of 2.86:1:1.48, 1.26:1:1, 1.58:1.80:1, respectively. Furthermore, SEM analysis demonstrated that the three polysaccharide fractions differ in microstructure and surface morphology. Additionally, preliminary results for immune-enhancing and anticancer activities reveal that these EPSs significantly induced the production of nitric oxide (NO), TNF-α, and IL-6 in Ana-1 cells and peritoneal macrophage cells. Meanwhile, the EPSs also significantly suppressed the proliferation of HCT-116, BCG-803, and particularly A-2780 cells. The results suggest that the three novel EPSs isolated from Lactobacillus pantheris TCP102 can be regarded as potential application value in functional food and natural antitumor drugs.

Strain-specific regulative effects of Lactobacillus plantarum on intestinal barrier dysfunction are associated with their capsular polysaccharides

The intestinal barrier is integral to the host's defense, and disrupting its integrity contributes to gut and systemic diseases. Lactobacillus plantarum has been widely reported to exhibit a protective effect on the gut barrier. However, the strain-specific mechanism of this bacterium's function remains unclear. This study characterized the regulative effects of 55 L. plantarum strains on the intestinal barrier using TNF-α-induced Caco-2 cells and a dextran sulfate sodium-induced colitis animal model and found that the regulative effect is strain-specific. Comparative genomic analysis suggested that the ability of L. plantarum to regulate the intestinal barrier is exerted in part by genes encoding proteins associated with polysaccharide synthesis. This observation was verified using surface protein/capsular polysaccharides separation experiments. Structural analysis of capsular polysaccharides showed that molecular weight and mole ratios of monosaccharide compositions may play important roles in strain-specific protective effects on the gut barrier. This study identified different effects of L. plantarum strains on intestinal barrier dysfunction and proved that this regulative ability relies on the characteristic of the capsular polysaccharides of the strains. Thus, our data provided genetic targets and molecular for screening L. plantarum strains with the ability to protect the gut barrier, and suggested the capsular polysaccharides of L. plantarum may be explored as a potential functional food component against intestinal barrier dysfunction.

Characterization of exopolysaccharide produced by Levilactobacillus brevis HDE-9 and evaluation of its potential use in dairy products

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

Structure of a unique fucose-containing exopolysaccharide from Sayram ketteki yoghurt and its anti-MRSA biofilm effect

In this work, we reported an in situ exopolysaccharide (in situ-EPS1) containing rare fucose produced by Lactobacillus helveticus MB2-1 in Sayram ketteki yoghurt, which made it unique. Its fine structure was characterized by GPC, HPLC, FT-IR, GC-MS,¹HNMR and ¹³CNMR together with two-dimensional (2D) NMR spectra. The results revealed that in situ-EPS1 was a new heteropolysaccharide with molecular weight of 1.06 × 10⁵ Da, and was composed of mannose, rhamnose, glucose, galactose and fucose with the following repeating units. Furthermore, the in situ-EPS1 exhibited significant antibiofilm effect against Methicillin-resistant Staphylococcus aureus (MRSA). Notably, the in situ-EPS1 did not interfere with the planktonic growth of MRSA strain, whereas inhibited its cell metabolic activity and the transcription of genes related to biofilm formation. This unique antibiofilm but non-antibacterial mechanism supposedly prevented the development of bacterial drug resistance, which may open a new door to fight against these drug-resistant microorganisms.

Exopolysaccharide Produced by Pediococcus pentosaceus E8: Structure, Bio-Activities, and Its Potential Application

The novel exopolysaccharide EPS-E8, secreted by Pediococcus pentosaceus E8, was obtained by anion-exchange and gel filtration chromatography. Structural analyses identified EPS-E8 as a heteropolysaccharide containing mannose, glucose, and galactose. Its major backbone consists of →2)-α-D-Manp-(1→2,6)-α-D-Glcp-(1→6)-α-D-Manp-(1→, and its molecular weight is 5.02 × 10⁴ g/mol. Using atomic force microscopy and scanning electron microscopy, many spherical and irregular reticular-like shapes were observed in the microstructure of EPS-E8. EPS-E8 has outstanding thermal stability (305.7°C). Both the zeta potential absolute value and average particle diameter increased gradually with increasing concentration. Moreover, at a concentration of 10 mg/ml, the antioxidant capacities of, 1-Diphenyl-2-picrylhydrazyl (DPPH), ABTS and hydroxyl radical were 50.62 ± 0.5%, 52.17 ± 1.4%, and 58.91 ± 0.7%, respectively. EPS-E8 possesses excellent emulsifying properties against several food-grade oils, and its activity is retained under various conditions (temperature, pH, and ionic strength). Finally, we found that EPS-E8 as a polysaccharide-based coating could reduce the weight loss and malondialdehyde (MDA) content of strawberry, as well as preserving the vitamin C and soluble solid content during storage at 20°C. Together, the results support the potential application of EPS-E8 as an emulsifier, and a polysaccharide-based coating in fruit preservation.

Biopolymer from Water Kefir as a Potential Clean-Label Ingredient for Health Applications: Evaluation of New Properties

The present work aimed to characterize the exopolysaccharide obtained from water kefir grains (EPSwk), a symbiotic association of probiotic microorganisms. New findings of the technological, mechanical, and biological properties of the sample were studied. The EPSwk polymer presented an Mw of 6.35 × 10⁵ Da. The biopolymer also showed microcrystalline structure and characteristic thermal stability with maximum thermal degradation at 250 °C. The analysis of the monosaccharides of the EPSwk by gas chromatography demonstrated that the material is composed of glucose units (98 mol%). Additionally, EPSwk exhibited excellent emulsifying properties, film-forming ability, a low photodegradation rate (3.8%), and good mucoadhesive properties (adhesion Fmax of 1.065 N). EPSwk presented cytocompatibility and antibacterial activity against Escherichia coli and Staphylococcus aureus. The results of this study expand the potential application of the exopolysaccharide from water kefir as a potential clean-label raw material for pharmaceutical, biomedical, and cosmetic applications.

Characterization on structure and bioactivities of an exopolysaccharide from Lactobacillus curvatus SJTUF 62116

This study aimed to investigate the chemical structure, physicochemical properties, antioxidant capacity, antibacterial ability and anti-biofilm formation activity of an exopolysaccharide (EPS) produced by Lactobacillus curvatus SJTUF 62116 from the fish Gymnocypris przewalskii. The purified EPS, denoted as EPS-1, was mainly composed of glucose and mannose at a relative molar ratio of 1:1.05 with molecular weight of 31.9 kDa. The chemical structure of EPS-1 was consisted of →2)-α-D-Manp-(1→, →4)-α-D-Manp-(1→, →3,6)-α-D-Manp-(1→, T-β-D-Glcp-(1→, →6)-β-D-Glcp-(1→, and →3)-β-D-Glcp-(1→ glycosidic bonds. A sheet-like structure of dried EPS-1 was determined by scanning electron microscope (SEM), whilst a peak-shaped structure of EPS-1 was observed by atomic force microscope (AFM). The degradation temperature of EPS-1 was determined as 300.21 °C using thermogravimetric analysis (TGA). Moreover, the antioxidant capacity of EPS-1 at a concentration of 5.0 mg/mL against DPPH and ABTS was 84.50% and 92.53%, respectively. Furthermore, EPS-1 exhibited acceptable bacteriostatic efficacy against S. Enteritidis, E. coli, and S.aureus with significant inhibition of S. Enteritidis biofilm formation.

Screening, optimization and characterization of exopolysaccharides produced by novel strains isolated from Moroccan raw donkey milk

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EPS producing bacteria was isolated and identified as Leuconostoc mesenteroides SL and Enterococcus viikkiensis N5.

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Optimization was carried out by Response Surface Methodology using Box Behnken Design.

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The GC–MS, FTIR, and NMR analysis showed that the EPS-SL and EPS-N5 are heteropolysaccharides connected by α-(1 → 6) and -(1 → 3) linkages.

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Both EPSs has high thermal stability.

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EPS exhibited appreciable antibacterial and antioxidant activity.

Two exopolysaccharides (EPS) producing strains, isolated from raw donkey milk were identified as Leuconostoc mesenteroides SL and Enterococcus viikkiensis N5 using 16S rDNA sequencing. The Box Benheken design exhibited the highest yield of EPS-SL (672.342 mg/L) produced by SL and of EPS-N5 (901 mg/L) produced by N5. The molecular weight was 1.68×10⁴ for EPS-SL and 1.55×10⁴ Da for EPS-N5. FTIR, NMR and GC–MS analysis showed that the EPS are heteropolysaccharides. The SEM image showed that the EPS-SL was smooth and represented a lotus leaf shape and EPS-N5 revealed a stiff-like, porous appearance and was more compact than EPS-SL. The TGA analyses showed high thermal stability and degradation temperature. Additionally, the two EPSs possessed antibacterial and antioxidant activity, and the EPS-SL had the stronger antioxidant activity. Consequently, these results suggest that the functional and biological properties of EPS-SL and EPS-N5 imply the potential application in the food and pharmaceutical industries.

Physicochemical and Anti-UVB-Induced Skin Inflammatory Properties of Lacticaseibacillus paracasei Subsp. paracasei SS-01 Strain Exopolysaccharide

The exopolysaccharide secreted by Lacticaseibacillus paracasei subsp. paracasei SS-01 strain (LP-EPS) is isolated and purified from yogurt. It is a polysaccharide with a branched and multi-stranded structure, which exists in a smooth rod-like or cloud-like state, and possesses a good thermal stability and a molecular weight of 49.68 kDa (±4.436%). LP-EPS shows a high antioxidant capacity, anti-inflammatory and anti-sensitizing activity during in vitro experimental studies, with half clearance (IC50) rates of 0.449, 1.314, and 2.369 mg/mL for the ABTS, DPPH, and OH radicals, respectively, and a half inhibition rate (IC50) of hyaluronidase of 1.53 mg/mL. A cell-based assay, enzyme-linked immunosorbent assay (ELISA), and quantitative real-time fluorescence PCR (qRT-PCR) show that LP-EPS effectively treats or ameliorates the skin inflammatory responses triggered by UVB irradiation, as evidenced by a highly significant decrease in the secretion of inflammatory factors by human skin keratinocytes (HaCaT), and a highly significant downregulation of the mRNA expression of MAPK/AP-1 pathway cytokines.

Fucose-containing bacterial exopolysaccharides: Sources, biological activities, and food applications

Bacterial exopolysaccharides are high molecular weight polysaccharides that are secreted by a wide range of bacteria, with diverse structures and easy preparation. Fucose, fucose-containing oligosaccharides (FCOs), and fucose-containing polysaccharides (FCPs) have important applications in the food and medicine fields, including applications in products for removing Helicobacter pylori and infant formula powder. Fucose-containing bacterial exopolysaccharide (FcEPS) is a prospective source of fucose, FCOs, and FCPs. This review systematically summarizes the common sources and applications of FCPs and FCOs and the bacterial strains capable of producing FcEPS reported in recent years. The repeated-unit structures, synthesis pathways, and factors affecting the production of FcEPS are reviewed, as well as the degradation methods of FcEPS for preparing FCOs. Finally, the bioactivities of FcEPS, including anti-oxidant, prebiotic, anti-cancer, anti-inflammatory, anti-viral, and anti-microbial activities, are discussed and may serve as a reference strategy for further applications of FcEPS in the functional food and medicine industries.

Functional and health-promoting properties of probiotics' exopolysaccharides; isolation, characterization, and applications in the food industry

Exopolysaccharides (EPS) are extracellular sugar metabolites/polymers of some slim microorganisms and, a wide variety of probiotics have been broadly investigated for their ability to produce EPS. EPS originated from probiotics have potential applications in food, pharmaceutical, cosmetology, wastewater treatment, and textiles industries, nevertheless slight is recognized about their function. The present review purposes to comprehensively discuss the structure, classification, biosynthesis, extraction, purification, sources, health-promoting properties, techno-functional benefits, application in the food industry, safety, toxicology, analysis, and characterization methods of EPS originated from probiotic microorganisms. Various studies have shown that probiotic EPS used as stabilizers, emulsifiers, gelling agents, viscosifiers, and prebiotics can alter the nutritional, texture, and rheological characteristics of food and beverages and play a major role in improving the quality of these products. Numerous studies have also proven the beneficial health effects of probiotic EPS, including antioxidant, antimicrobial, anti-inflammatory, immunomodulatory, anticancer, antidiabetic, antibiofilm, antiulcer, and antitoxin activities. Although the use of probiotic EPS has health effects and improves the organoleptic and textural properties of food and pharmaceutical products and there is a high tendency for their use in related industries, the production yield of these products is low and requires basic studies to support their products in large scale.

Structural and bioactive characteristics of a dextran produced by Lactobacillus kunkeei AK1

In this study, structural and techno-functional characteristics of an exopolysaccharide (EPS) produced by Lactobacillus kunkeei AK1 were determined. High-performance liquid chromatography (HPLC) analysis demonstrated that EPS AK1 was composed of only glucose units. 1H and 13C Nuclear magnetic resonance (NMR) analysis revealed that EPS AK1 was a dextran type EPS containing 4.78% (1 → 4)-linked α-d-glucose branches. The molecular weight of EPS AK1 was determined to be 45 kDa by Gel Permeation Chromatography (GPC) analysis. A high level of thermal stability up to 280 °C was determined for dextran AK1 detected by Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA). Dextran AK1 appeared as regular spheres with compact morphology and as irregular particles in the solution with no clear cross-linking between the chains of the polysaccharide observed by Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) analysis, respectively. X-ray diffraction analysis (XRD) analysis demonstrated that dextran AK1 had a crystalline structure. A relatively strong antioxidant activity was observed for dextran AK1 determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging and cupric reducing antioxidant capacity (CUPRAC) tests. Finally, only a digestion ratio of 3.1% was observed for dextran AK1 following the in vitro simulated gastric digestion test.

High-Efficiency Production of Auricularia polytricha Polysaccharides Through Yellow Slurry Water Fermentation and Its Structure and Antioxidant Properties

Yellow slurry water is a kind of nutrient-rich wastewater of tofu. Firstly, the medium of yellow slurry was optimized. Then, APP40, APP60, and APP80 were obtained by sedimentation with different concentration of ethanol (40, 60, and 80%). The physicochemical properties and primary structures of the three polysaccharides were studied by high performance anion exchange chromatography (HPAEC), high performance gel filtration chromatography (HPGFC), scanning electron microscope (SEM), atomic force microscope (AFM), and Fourier transform infrared (FT-IR) spectrometer. Finally, the effects of three polysaccharides on antioxidation activity were studied. According to the experimental optimization the results, the biomass and the production of Auricularia polytricha Polysaccharides (APPS) reached the peak, and they were 13.5 ± .655 and 9.42 ± .253 g/L (p < .05). The SEM and the AFM showed that the height of APP80 gradually increased from 31.1 to 46.7 nm and from APP40 to APP80. The particle size of APP80 increased, the pores decrease or even disappear, and the molecules begin to aggregate. The FT-IR spectrum analysis showed that the three polysaccharides possessed key functional groups. The carbohydrate content of APP40, APP60, and APP80 was 20.2, 34.25, and 31.73%. The molecular weights of APP40, APP60, and APP80 are 9.462 × 10⁴, 8.742 × 10⁴, and 8.091 × 10⁴ Da, respectively. The three polysaccharides were composed of rhamnose, galactose, glucose, mannose, and xylose but with different molar ratio. APP80 showed strong reducing ability and scavenging activity of 2,2–diphenyl–1–picrylhydrazyl (DPPH) and hydroxyl radicals through antioxidant activities evaluated in vitro. This study introduces a way for the effective use of yellow slurry water.

Exopolysaccharides from a Scandinavian fermented milk viili increase butyric acid and Muribaculum members in the mouse gut

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Bioactivity of viili exopolysaccharide (VEPS) were determined in young male mice.

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Mice drank daily tap water supplemented with VEPS, stressless administration.

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A low dose VEPS modified mildly but significantly the gut microbiota.

Starter culture of viili contains lactic acid bacteria belonging to Lactococcus lactis. These bacteria secrete large polysaccharides (EPSs) into milk, resulting in a ropy texture of viili. In mouse experiments, a large dose of EPS (5–140 mg/day) has been shown to alleviate severity of artificially induced illness through modulation of the gut microbiota. The present study investigated whether supplementary amounts of EPS affects the gut microbiota of normal mouse. EPS with high glucosamine content (VEPS) was isolated from home-made viili. C57BL/6J male mice fed ordinary diet took 49 ± 1 μg VEPS/day for 28 days by drinking ad libitum tap water containing 8 μg/mL VEPS. The relative abundance of Muribaculum increased significantly by VEPS supplementation. The relative abundance of fecal butyric acid decreased in control mice, and VEPS prevented this decrease. These findings indicated that the gut microbiota can be modulated by a small dose of VEPS.

Structural Characterization and Antioxidant Activity of Exopolysaccharide from Soybean Whey Fermented by Lacticaseibacillus plantarum 70810

Soybean whey is a high-yield but low-utilization agricultural by-product in China. In this study, soybean whey was used as a substrate of fermentation by Lacticaseibacillus plantarum 70810 strains. An exopolysaccharide (LPEPS-1) was isolated from soybean whey fermentation by L. plantarum 70810 and purified by ion-exchange chromatography. Its preliminary structural characteristics and antioxidant activity were investigated. Results show that LPEPS-1 was composed of mannose, glucose, and galactose with molar ratios of 1.49:1.67:1.00. The chemical structure of LPEPS-1 consisted of →4)-α-D-Glcp-(1→, →3)-α-D-Galp-(1→ and →2)-α-D-Manp-(1→. Scanning electron microscopy (SEM) revealed that LPEPS-1 had a relatively rough surface. In addition, LPPES-1 exhibited strong scavenging activity against DPPH and superoxide radicals and chelating ability on ferrous ion. This study demonstrated that soybean whey was a feasible fermentation substrate for the production of polysaccharide from L. plantarum 70810 and that the polysaccharide could be used as a promising ingredient for health-beneficial functional foods.

Anti-Helicobacter pylori Activity of a Lactobacillus sp. PW-7 Exopolysaccharide

Helicobacter pylori is a cause of gastric cancer. We extracted the exopolysaccharide (EPS) of Lactobacillus plajomi PW-7 for antibacterial activity versus H. pylori, elucidating its biological activity and structural characteristics. The minimum inhibitory concentration (MIC) of EPS against H. pylori was 50 mg/mL. Disruption of the cell membranes of pathogenic bacteria by EPS was indicated via the antibacterial mechanism test and confirmed through electron microscopy. EPS also has antioxidant capacity. The IC₅₀ of EPS for 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide anions, and hydroxyl radicals were 300 μg/mL, 180 μg/mL, and 10 mg/mL, respectively. The reducing power of EPS was 2 mg/mL, equivalent to 20 μg/mL of ascorbic acid. EPS is a heteropolysaccharide comprising six monosaccharides, with an approximate molecular weight of 2.33 × 10⁴ Da. Xylose had a significant effect on H. pylori. EPS from L. plajomi PW-7 showed potential as an antibacterial compound and antioxidant, laying a foundation for the development of EPS-based foods.