Exopolysaccharides produced by Pediococcus acidilactici MT41-11 isolated from camel milk: Structural characteristics and bioactive properties

Bacterial exopolysaccharide and metal-doped bioactive glass nanoparticles-based electrospun membranes for chronic wound healing

Healing of chronic wounds requires interactive dressings that not only meet basic biological criteria, of biocompatibility, but also offer additional functionalities such as antioxidant and antibacterial properties. In this study, three novel multifunctional nanofibrous membranes based on EPS, an α-glucan exopolysaccharide produced by Lacticaseibacillus rhamnosus P14, blended with PEO as a co-polymer were successfully developed using electrospinning. The membranes incorporated Cu or Ag-doped bioactive glass (BG) nanoparticles, to enhance their functionalities. The structural and thermal properties of the electrospun membranes were characterized using FT-IR, TGA, and DSC analysis. In addition, the surface morphology, fiber size, and porosity were examined by SEM analysis. Additionally, their biological properties, including antioxidant and antibacterial activities, were thoroughly investigated. SEM confirmed the effective electrospinning of the EPS-PEO and EPS-PEO-BG blends from aqueous solutions using optimized process parameters, resulting in the successful incorporation of the BG nanoparticles and uniform fibers with average diameter ranging from 270 to 352 nm. Moreover, DPPH RSA and FRAP assays showed a significant antioxidant capacity for all prepared membranes which is attributed to the EPS component. Moreover, the antibacterial activity revealed a notable inhibition against E. coli and S. aureus after 24 h exposure to the composite membranes. This work presents a novel synergistic approach to developing multifunctional wound dressing by combining the antioxidant properties of EPS, the antibacterial activity of ion-doped bioactive glass nanoparticles, and structural benefits of electrospinning.

Novel exopolysaccharide from Limosilactobacillus fermentum A10: Biosynthesis, physicochemical properties and antioxidant activity

In this study, the biosynthesis, physicochemical properties and antioxidant activity of novel EPS from Limosilactobacillus fermentum A10 were investigated. Whole genome sequencing and functional annotation were employed to identify genes involved in the EPS synthesis and the Wzx/Wzy-dependent pathway. After being purified by a DEAE-52 cellulose column, the main component EPS-1, which consisted of rhamnose, galactose, glucose, mannose, and glucuronic acid, was isolated and prepared. Structural analysis indicated that EPS-1 was a heteropolysaccharide containing a pyranose ring with a zeta potential of -18 mV and a particle size of 146 nm. EPS-1 had a loose, porous, crystalline structure and had thermal stability of up to 257.80 °C. EPS-1 exhibited high radical scavenging activity and cytoprotective effect against H2O2-induced HepG2 cellular oxidative damage and significantly increased the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT). Moreover, EPS-1 induced antioxidant mechanisms by activating the Keap1-Nrf2/ARE signaling pathway. Molecular docking results indicated that the main interactions between Keap1 protein and rhamnose, galactose, glucose, mannose, and glucuronic acid are hydrogen bonds (NH and OH) and electrostatic interactions (amide bonds). These results demonstrated that EPS-1 can potentially be used in functional food to target Keap1 inhibitors/Nrf2 activators.

Complete Genome Sequence and Probiotic Properties of Pediococcus acidilactici CLP03 Isolated from Healthy Felis catus

Probiotics are available from various sources, including the gastrointestinal tract of healthy animals. In this study, Pediococcus acidilactici was isolated for the first time from Felis catus and evaluated for its functionality. The findings revealed that P. acidilactici CLP03 exhibited inhibitory properties against pathogenic bacteria (E. coli, Salmonella, S. aureus, P. aeruginosa, and L. monocytogenes). Then, survival of strains exposed to pH 2.5, 0.3% bile salts, 0.5% bile salts, and gastrointestinal fluids was 63.97%, 98.84%, 87.95%, and 52.45%, respectively. Also, P. acidilactici CLP03 demonstrated high hydrophobicity (69.63-82.03%) and self-aggregation (73.51-81.44%), negative for hemolytic, and was susceptible to clindamycin. Finally, the scavenging rates of DPPH, ABTS, and O2- were 53.55%, 54.81%, and 85.13%, respectively, which demonstrated that the strain CLP03 has good oxidation resistance. All these characteristics contribute to the survival, colonization, and functionality of the strain in the gastrointestinal tract, indicating their excellent probiotic potential. On the other hand, animal experiments (KM mice, randomly assigned to four groups) showed that the gavage of CLP03 had no toxic effects on mice, increased the serum SOD content, and decreased the MDA and BUN contents, which revealed gavage of CLP03 significantly increased the antioxidant capacity of mice in vivo. In addition, complete genome annotation showed that P. acidilactici CLP03 had 1976 CDS genes, and the numbers of CRISPR, gene islands, and phages were 8, 3, and 6, respectively. In conclusion, P. acidilactici CLP03 could be a candidate functional cat probiotic to enhance animal health and welfare.

Exopolysaccharide from Bifidobacterium longum subsp. infantis E4: Structural analysis and immunoregulation activities

Exopolysaccharides (EPS) have the effects of anti-inflammatory, antimicrobial and immunomodulatory. This study described the structural characteristics of EPS-1 and EPS-2 and investigated their modulatory effects on immunity by cyclophosphamide (CTX)-induced immunocompromised mice. EPS-1 primarily consisted of glucose and mannose. EPS-2 was mostly comprised of galactose, glucose and mannose. Fourier-transform infrared (FT-IR) analysis revealed that EPS-1 and EPS-2 exhibited absorption peaks including CH and CO groups. Congo red test indicated that both of them had triple-helical conformations. Methylation and nuclear magnetic resonance (NMR) analyzed the main chain of EPS-1 comprising →4,6)-α-D-Glcp-(1→,→4)-α-D-Glcp-(1→,→4,6)-α-D-Glcp-(1→,2)-α-D-Manp-(1→,→6)-α-D-Manp-(1→. The main chain of EPS-2 was composed of α-D-Manp-(1→,→4)-α-D-Galp-(1→,→2,6)-α-D-Glcp-(1→,→2)-α-D-Manp-(1→,3)-α-D-Glcp-(1→. Additionally, EPS-1 and EPS-2 alleviated decreases in spleen and thymus index in mice subjected to CTX induction. Compared with the Model control (MC) group, the Splenic lymphocyte proliferations and NK cell activity in EPS-1 and EPS-2 groups were increased. Th1, Th2, Th17 and Treg cells in EPS-1 group were increased to 5.50 %, 0.36 %, 2.87 %, 3.53 %, respectively, and 5.39 %, 0.33 %, 2.40 %, 3.33 % in EPS-2 group. The levels of serum inflammatory cytokines (such as IFN-γ, IL-1β, IL-2, IL-6, IL-10 and TNF-α) were also increased in EPS-1 and EPS-2 groups to varying degree compare with the MC group. Therefore, the results unveiled that EPS has the potential to regulate the body immunity function.

Structural characterization and in vitro anti-inflammatory activity of exopolysaccharide produced by Pediococcus pentosaceus 4412

Probiotic-derived exopolysaccharides (EPSs) exert significant beneficial effects by regulating the human immune system. In this study, EPS-4412 was extracted from Pediococcus pentosaceus 4412, which was isolated from fermented Manilkara zapota juice. After purification by ion exchange and gel filtration chromatography, its average molecular mass and total carbohydrate content were measured to be 74 kDa and 95.6 ± 0.28 %, respectively. EPS-4412 was characterized as a neutral heteropolysaccharide, primarily composed of mannose with traces of glucose and rhamnose, in a molar ratio of 90.5: 3.48:1, as determined by ultra-high-performance liquid chromatography (UPLC). Fourier transform infrared spectroscopy (FTIR) analysis confirmed the presence of functional groups, OH, CH, CO, and C-O-C in EPS-4412. The existence of α- and β-glycosidic linkages, such as →2)-α-D-Manp-(1→, →3)-α-D-Manp-(1→, →6)-α-D-Manp-(1→, →5)-α-D-Manp-(1→, →4)-α-D-Manp-(1→, →6)-α-D-Glcp-(1 → and →2)-β-D-Rhap-(1 → was elucidated using nuclear magnetic resonance (NMR) spectroscopy. EPS-4412 was further characterized as smooth, glossy, irregular, compact, stacked flaky structures, semi-crystalline, and thermally stable at 252.86 °C using analytical techniques like scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). In vitro anti-inflammatory activity on LPS-stimulated macrophages of EPS-4412 manifested the inhibition of proinflammatory cytokines (IL-6 and TNF-α) and stimulation of the anti-inflammatory cytokine IL-10. Hence, EPS-4412 could be potentially used as a natural additive in the food and pharmaceutical industry.

Structural characterization of polysaccharide from an edible fungus Dictyophora indusiata and the remodel function of gut microbiota in inflammatory mice

Dictyophora indusiata is an edible fungus, which is known as bamboo fungus. D. indusiata polysaccharide is considered as the most important bioactive component. The aim of this study was to investigate the structure of a polysaccharide fraction from D. indusiata and the effects of D. indusiata polysaccharide on gut microbiota and metabolites in inflammatory mice. Here, the DIP1p, a polysaccharide fraction from D. indusiata, was obtained by isolation and purification using Cellulose DE-52 column and Sephadex G-200 gel column. The results showed that DIP1p is a heteropolysaccharide consisting of glucose, mannose, galactose and xylose in the ratio of 55.2 %, 28.6 %, 10.3 % and 5.9 %, which mainly linked by →3)-Glcp-(1 → glycosidic bonds. In addition, D. indusiata polysaccharide restored the colonic length reduction, modulated the secretion of cytokine and mitigated histological damage. It is remarkable that D. indusiata polysaccharide enhanced the abundance of beneficial bacteria Blautia and Roseburia, and increased the levels of short-chain fatty acids including acetic acid and propionic acid. Our findings indicated that D. indusiata polysaccharide remodeled gut microbiota and enhanced short-chain fatty acids levels to alleviate the inflammation.

In Vitro Cholesterol-Lowering Bioactivity, Synthetic Pathway, and Structural Characterization of Exopolysaccharide Synthesized by Schleiferilactobacillus harbinensis Z171

A strain identified as Schleiferilactobacillus harbinensis was isolated from Chinese sauerkraut, and its exopolysaccharide (EPS) exhibited excellent in vitro cholesterol-lowering bioactivity. Besides, the whole genome of this strain and the structure characteristics of the purified EPS were investigated in this study. S. harbinensis Z171 presented a strong EPS production capacity, with five nucleotide sugar biosynthesis pathways regulated by an EPS synthesis gene cluster. Structural characterization revealed that the purified fraction F-EPS1A was a neutral polysaccharide with a molecular weight of 6.4 × 104 Da. The structure of F-EPS1A contained a backbone that comprised blocks of four 1,2-linked and three 1,3-linked alpha mannose units. Some 1,2-linked alpha mannose residues were branched at C6 with side chains formed by single alpha mannose or a disaccharide consisting of 1,6-linked alpha mannose residues. The structural characteristics endowed F-EPS1A with a high level of cholesterol-lowering bioactivity. In addition, whole genome analysis indicated that S. harbinensis Z171 possessed a strong EPS production capacity. These findings suggested that the EPS produced by S. harbinensis Z171 could be applied as a potential cholesterol-lowering prebiotic agent or supplement in functional food.

A polysaccharide from Glycyrrhiza uralensis attenuates myocardial fibrosis via modulating the MAPK/PI3K/AKT signaling pathway

Myocardial fibrosis (MF) is a key factor endangering public health worldwide. Glycyrrhiza uralensis polysaccharide (GPS) exhibits various biological activities. However, its activity against MF has not been reported. Herein, a neutral polysaccharide (GPS-1-1) was isolated from GPS through column chromatography, its structure was characterized and potential mechanism regarding anti-MF activity was evaluated. Notably, the molecular weight of GPS-1-1 was 14.073 kDa, and the monosaccharides consist of glucose, arabinose and galactose, with a → 4)-α-d-glucopyranose (Glcp)-(1 → and →4, 6)-α-D-Glcp-(1 → backbone. Western blotting and immunofluorescence showed that GPS-1-1 inhibited the expression of fibrosis-related proteins, such as Collagen, Vimentin, Fibronectin and α-SMA in TGF-β1-induced fibrosis of cardiac fibroblasts (CFs), and inhibited the expression of TGF-β1-induced CFs migration ability and matrix metalloproteinases (MMP-2 and MMP-9), thus inhibiting the deposition of extracellular matrix in CFs. Additionally, in vivo analysis showed that GPS-1-1 reduced inflammatory cell infiltration and collagen deposition in cardiac tissues of mice with MF, and it inhibited the expression of serum lactate dehydrogenase, creatine kinase, and fibrosis-related factors. Combined transcriptomics, molecular docking and Western blotting analysis showed that platelet-derived growth factor subunit B (PDGFB) was involved in the anti-fibrosis process of GPS-1-1. Furthermore, qRT-PCR and Western blotting showed that GPS-1-1 inhibited the expression of MAPK/PI3K/AKT pathway related proteins, such as ERK, p-ERK, JNK, PI3K and p-PI3K in TGF-β1-induced CFs through PDGFB. Altogether, this study showed that GPS-1-1 inhibits the activation of the MAPK/PI3K/AKT pathway by down-regulating PDGFB expression to exert its anti-MF activity and its potential to be developed as a functional food and drug.

Structure of Extracellular Vesicles and Their Effect on Bacterial Biofilms Change with the Development of Antibiotic Resistance in the Probiotic Strain Lactiplantibacillus plantarum 8p-a3

Significant changes in lactobacillus-derived extracellular membrane vesicles, which transfer lipids, polysaccharides, proteins, and nucleic acids, were for the first time observed to accompany the development of resistance to antibiotics (amoxicillin and clarithromycin) in vitro in the probiotic strain Lactiplantibacillus plantarum 8p-a3. The changes occur together with large-scale genome rearrangements, changes in the profile of phenotypic sensitivity to antimicrobials of various groups, and evolution of virulence. Changes in vesicles affected their structure, composition, and activity against biofilms of opportunistic bacteria. The data provide for a better understanding of the molecular mechanisms of microbial survival under selective pressure of antimicrobials, the functional potential of probiotic vesicles, and probiotic safety assessments.

Antioxidant potential of exopolysaccharides from lactic acid bacteria: A comprehensive review

Exopolysaccharides (EPSs) from lactic acid bacteria (LAB) have multifunctional capabilities owing to their diverse structural conformations, monosaccharide compositions, functional groups, and molecular weights. A review paper on EPS production and antioxidant potential of different LAB genera has not been thoroughly reviewed. Therefore, the current review provides comprehensive information on the biosynthesis of EPSs, including the isolation source, type, characterization techniques, and application, with a primary focus on their antioxidant potential. According to this review, 17 species of Lactobacillus, five species of Bifidobacterium, four species of Leuconostoc, three species of Weissella, Enterococcus, and Lactococcus, two species of Pediococcus, and one Streptococcus species have been documented to exhibit antioxidant activity. Of the 111 studies comprehensively reviewed, 98 evaluated the radical scavenging activity of EPSs through chemical-based assays, whereas the remaining studies documented the antioxidant activity using cell and animal models. Studies have shown that different LAB genera have a unique capacity to produce homo- (HoPs) and heteropolysaccharides (HePs), with varied carbohydrate compositions, linkages, and molecular weights. Leuconostoc, Weissella, and Pediococcus were the main HoPs producers, whereas the remaining genera were the main HePs producers. Recent trends in EPSs production and blending to improve their properties have also been discussed.

Exopolysaccharides of lactic acid bacteria as protective agents against bacterial and viral plant pathogens

In this study, 25 exopolysaccharides produced by lactic acid bacteria (LAB) were screened for their effect on plant pathogens. The molecular masses of EPS were found to be 3,8-5,0 × 104 Da. The GC-MS analysis revealed that EPSs were majorly composed of glucose (85.85-97.98 %). The FT-IR spectra of EPSs were in agreement with the typical absorption peaks of polysaccharides. EPSs showed a hydroxyl radical scavenging ability. The scavenging rate of EPS ranged from 20 to 50 % at a concentration of 5.0 mg/mL. Significant growth delay of phytopathogenic bacteria was observed after 3-6 h of cultivation. Optical density values of indicator cultures growing in the medium with EPS (1 mg/mL) were lower compared to the control by 24-100 % for Pseudomonas fluorescens, 9-46 % for P. syringae, 47-79 % for Pectobacterium carotovorum, 14-90 % for Clavibacter michiganensis, 9-100 % for Xantomonas campestris, and 45-100 % for X. vesicatorium. EPS retained their inhibitory effect on the growth of X. campestris, X. vesicatorium and C. michiganensis strains after 24-48 h of cultivation, but stimulating effect on the growth of some strains also was observed. LAB EPS showed antibiofilm activity against P. carotovorum, P. syringae, and P. fluorescent, decreasing their biofilm formation by 16-50 %, 14-39 %, and 29-59 %, respectively. Also, stimulation of biofilm formation by X. campestris (by 8-29 %), X. vesicatorium (by 3-32 %) and C. michiganensis (by 31-41 %) strains was observed. EPSs showed antiviral activity against tobacco mosaic virus (TMV). At a concentration of 100 μg/mL, they decreased the infective ability of TMV by 61-92 %. This is the first study demonstrating that LAB EPS exhibited in vitro antibacterial and antibiofilm activity against phytopathogenic bacteria and anti-viral activity against TMV. Thus, LAB EPSs could have great potential for plant protection strategies.

Antilisterial and antioxidant exopolysaccharide from Enterococcus faecium PCH.25 isolated from cow butter: characterization and probiotic potential

Exopolysaccharides produced by lactic acid bacteria have gained attention for their potential health benefits and applications in functional foods. This study explores the isolation and characterization of a novel exopolysaccharide-producing strain from dairy products. The aim was to evaluate its probiotic potential and investigate the properties of the produced exopolysaccharide. A strain identified as Enterococcus faecium PCH.25, isolated from cow butter, demonstrated exopolysaccharide production. The study's novelty lies in the comprehensive characterization of this strain and its exopolysaccharide, revealing unique properties with potential applications in food, cosmetic, and pharmaceutical industries. The E. faecium PCH.25 strain exhibited strong acid tolerance, with a 92.24% viability rate at pH 2 after 2 h of incubation. It also demonstrated notable auto-aggregation (85.27% after 24 h) and co-aggregation abilities, antibiotic sensitivity, and absence of hemolytic activity, suggesting its probiotic potential. The exopolysaccharide produced by this strain showed bactericidal activity (MIC and MBC = 1.8 mg/ml) against Listeria monocytogenes and antioxidant properties (22.8%). Chemical analysis revealed a heteropolysaccharide composed of glucose and fructose monomers, with various functional groups contributing to its bioactivities. Physical characterization of the exopolysaccharide indicated thermal stability up to 270 °C, a negative zeta-potential (-27 mV), and an average particle size of 235 nm. Scanning electron microscopy and energy dispersive X-ray analysis revealed a smooth, nonporous structure primarily composed of carbon and oxygen, with an amorphous nature. These findings suggest that the exopolysaccharide from E. faecium PCH.25 has potential as a natural antibacterial and antioxidant polymer for use in functional foods, cosmetics, and pharmaceuticals.

Impact of Pediococcus acidilactici GLP06 supplementation on gut microbes and metabolites in adult beagles: a comparative analysis

There is growing interest in the potential health benefits of probiotics for both humans and animals. The study aimed to investigate the effects of feeding the canine-derived probiotic Pediococcus acidilactici GLP06 to adult beagles by analysing the microbiome and metabolome. Twenty-four healthy adult beagles were randomly assigned to four groups. The CK group received a standard diet, while the three probiotic groups, the LG group (2 × 108 CFU/day/dog), MG group (2 × 109 CFU/day/dog), and HG group (2 × 1010 CFU/day/dog), received the standard diet supplemented with varying amounts of probiotics. The results show that, compared to the CK group, total antioxidant capacity was significantly increased in the MG and HG groups (p < 0.05), and superoxide dismutase and catalase were significantly increased in the HG group (p < 0.05). Compared to the CK group, malondialdehyde and blood urea nitrogen content were significantly decreased in the MG and HG groups (p < 0.05). Additionally, secretory immunoglobulin A activity was significantly increased in the HG group compared to the CK and LG groups (p < 0.05), and immunoglobulin G activity was significantly increased in the HG group compared to the CK, LG, and MG groups (p < 0.05). In addition, compared with the CK group, the abundance of Faecalitalea and Collinsella increased in the LG group, and the relative abundance of Tyzzerella and Parasutterella increased in the MG group. The α diversity and the relative abundances of beneficial bacteria (Faecalibacterium, Lachnospiraceae_NK4A1316, and Ruminococcaceae_UCG-005) were higher in the HG group than in the CK group. Furthermore, acetic acid content was significantly increased in the HG group compared to the CK, LG, and MG groups (p < 0.05). Butyric acid, isobutyric acid, and the total SCFA content were significantly increased in the HG group compared to the CK group (p < 0.05). Moreover, metabolome analysis revealed 111 upregulated and 171 downregulated metabolites in the HG group. In conclusion, this study presents evidence that supplementing with P. acidilactici GLP06 can have a positive impact on antioxidant activity, immunoproteins, SCFAs, and gut microbiota in adult beagles. These findings highlight the potential of probiotics as a dietary intervention to enhance gut health and overall wellbeing in companion animals.

Structural Characterization and Functional Studies of Exopolysaccharide by Native Lacticaseibacillus rhamnosus P14 Isolated from the Moroccan Region

Exopolysaccharides (EPS) are natural polymers synthesized by several microorganisms, including lactic acid bacteria (LAB). They are characterized by a great structural diversity, which gives them interesting biological and pharmacological properties. This work investigates the physicochemical and biological characterization of a new exopolysaccharide (EPS) produced by a wild Lacticaseibacillus rhamnosus P14. The functional groups, chemical bonds, and thermal and morphological properties of the purified EPS-P14 were determined using Fourier Transform Infrared, Nuclear Magnetic Resonance, and X-ray diffraction spectroscopies, as well as Thermo-gravimetric analysis, Differential Scanning Calorimetry and Scanning Electron Microscopy. The functional properties, namely antioxidant and emulsifying activities, were also assessed. The physicochemical analysis revealed that EPS-P14 is a porous and thermally stable polysaccharide with a degradation temperature of 307 °C. NMR and FT-IR studies identified it as a homogeneous α-D-glucan with mainly α-(1 → 6) glycosidic linkage and some α-(1 → 3) branching. EPS-P14 was highly water-soluble and exhibited strong emulsifying and stabilizing properties in a concentration-dependent manner. Furthermore, EPS-P14 demonstrated significant DPPH scavenging and ferric-reducing capacities. These findings suggest that EPS-P14 is a bioactive polysaccharide with potential effects, which could be a promising natural candidate for prospective application.

Exopolysaccharides of lactic acid bacteria: Structure, biological activity, structure-activity relationship, and application in the food industry: A review

Over the past few decades, researchers have discovered that probiotics play an important role in our daily lives. With the further deepening of research, more and more evidence show that bacterial metabolites have an important role in food and human health, which opens up a new direction for the research of lactic acid bacteria (LAB) in the food and pharmaceutical industry. Many LAB have been widely studied because of the ability of exopolysaccharides (EPS). Lactic acid bacteria exopolysaccharides (LAB EPS) not only have great potential in the treatment of human diseases but also can become natural ingredients in the food industry to provide special qualitative structure and flavor. This paper has organized and summarized the biosynthesis, strain selection, production process parameters, structure, and biological activity of LAB EPS, filling in the monotony and incompleteness of previous articles' descriptions of LAB EPS. Therefore, this paper focuses on the general biosynthetic pathway, structural characterization, structure-activity relationship, biological activity of LAB EPS, and their application in the food industry, which will help to deepen people's understanding of LAB EPS and develop new active drugs from LAB EPS. Although the research results are relatively affluent, the low yield, complex structure, and few clinical trials of EPS are still the reasons that hinder its development. Therefore, future knowledge expansion should focus on the regulation of structure, physicochemical properties, function, higher production of EPS, and clinical trial applications, which can further increase the commercial significance and value of EPS. Furthermore, better understanding the structure-function relationship of EPS in food remains a challenge to date.

Effects of different stress conditions on the production, bioactivities, physicochemical and structural characteristics of exopolysaccharides synthetized by Schleiferilactobacillus harbinensis Z171

This study systematically investigated the effects of stress conditions including temperature, pH, H2O2, NaCl, antibiotics on the production and in vitro cholesterol-lowering activity of the exopolysaccharide (EPS) synthetized by Schleiferilactobacillus harbinensis Z171. Additionally, the influences of the optimal stress condition combined with different carbon sources on EPS production were examined, shedding light on the structural characteristics, physicochemical properties and bioactivities of EPSs. The results demonstrated that the EPS produced under H2O2 stress was optimal and presented excellent resistance to simulated gastric juice and α-amylase. Three main fractions, denoted as G-EPS1, F-EPS1 and S-EPS1, were isolated by cellulose DEAE-52 chromatography from crude EPSs synthetized using glucose, fructose and sucrose as carbon sources, respectively. Among them, F-EPS1 possessed the highest cholesterol-lowering, antioxidant and hypoglycemic activities, with the highest molecular weight 91.03 kDa, largest particle size 40.14 nm and apparent viscosity 288.2 mPa·s. Three EPSs exhibited irregular sheet-like and granular structures with good thermal stability. Structural characterization of F-EPS1a (a purified fraction from F-EPS1) revealed that it was a mannan mainly composed of →2)-α-D-Manp-(1→, →3)-α-Manp-(1→ and →2,6)-α-D-Manp-(1→ with branch chains containing α-D-Manp-(1→. F-EPS1a has more potential to be a natural cholesterol-lowering, hypoglycemic and antioxidant supplements in the food industry.

In vivo functional effects of Weissella confusa VP30 exopolysaccharides on loperamide-induced constipation in rats

In this work, the in vivo functionalities of milk fermented with Weissella confusa VP30 (VP30-EPS) and purified exopolysaccharide (pEPS) from the milk fermented with Weissella confusa VP30 were evaluated for their effect on constipation using an experimental constipated rat model. Rats were randomly divided into four groups: (i) control group (PBS administered normal group), (ii) loperamide treated group (constipation group), (iii) constipation with loperamide plus VP30-EPS (1 g/kg), and (iv) constipation with loperamide plus pEPS (0.6 g/kg) groups. Loperamide treatment induced animal constipation and significantly reduced the frequency of defecation, intestinal transit ratio, and water content of feces. However, all four fecal parameters were improved in both the loperamide plus VP30-EPS and pEPS administered groups as compared to the loperamide group. These results suggest that the addition of VP30-EPS potentially improves the functional laxative effects of commercial products. This study suggests the possibility that VP30-EPS can be applied to fermented and/or functional foods to relieve constipation.

Production, characterization and antioxidant activity of exopolysaccharide from Sporidiobolus pararoseus PFY-Z1

At present, the study on exopolysaccharid is mainly focused on lactic acid bacteria, and the research on exopolysaccharide produced by yeast, especially Sporidiobolus pararoseus, is relatively few. Therefore, the aim of this study was to explore the characterization and antioxidant activities of a novel neutral exopolysaccharide SPZ, which was isolated and purified from S. pararoseus PFY-Z1. The results showed that SPZ was mainly composed of mannose, followed by glucose, with a molecular weight was 24.98 kDa, had O-glycosidic bonds, no crystalline, and no triple helix structure. Based on fourier transform-infrared, high-performance liquid chromatography and nuclear magnetic resonance analyses, SPZ was identified to be a exopolysaccharide with some side chains, presence of α-, β-pyranose ring and nine sugar residues. Furthermore, the morphology features of SPZ have performed a relatively rough and uneven surface, covered with small pores and fissures. Moreover, SPZ had higher antioxidant activities and the maximum scavenging abilities of ⋅OH, NO₂^- and reducing power were 28.05 ± 0.73%, 92.76 ± 1.86% and 0.345 ± 0.024, respectively. Hence, SPZ could be used as a potential antioxidant application in the food and pharmaceutical industries.

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.

Exopolysaccharides synthesized by lactic acid bacteria: biosynthesis pathway, structure-function relationship, structural modification and applicability

Probiotics and their fermentation products are increasingly been focused on due to their health-boosting effects. Exopolysaccharides (EPS) synthetized by lactic acid bacteria (LAB) are widely applied as texture modifiers in dairy, meat and bakery products owning to their improved properties. Moreover, LAB-derived EPS have been confirmed to possess diverse physiological bioactivities including antioxidant, anti-biofilm, antiviral, immune-regulatory or antitumor. However, the low production and high acquisition cost hinder their development. Even though LAB-derived EPS have been extensively studied for their production-improving, there are only few reports on the systematic elucidation and summary of the relationship among biosynthesis pathway, strain selection, production parameter, structure-function relationship. Therefore, a detailed summary on biosynthesis pathway, production parameter and structure-function relationship of LAB-derived EPS is provided in this review, the structural modifications together with the current and potential applications are also discussed in this paper.