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In the present study, a novel exopolysaccharide EPS-BMD26 produced by cold-adapted yeast Rhodotorula glutinis was structurally examined, along with its rheological, antioxidant, and antibiofilm properties. High-performance liquid chromatography (HPLC) analysis revealed glucose and galactose as two monosaccharide constituents. The functional groups within the EPS-BMD26 structure were detected by Fourier transform infrared (FT-IR) spectroscopy. The 1H and 13C nuclear magnetic resonance (NMR) spectra of EPS-BMD26 also confirmed its β-D-glucan type with galactose residues with an average molecular weight of 118 kDa. Differential scanning calorimetry (DSC) analysis revealed that EPS-BMD26 had a high level of thermal stability, up to 326.16 °C. Scanning electron microscopy (SEM) analysis demonstrated that EPS-BMD26 had a porous microstructure with fissures. X-ray diffraction (XRD) analysis revealed its semi-crystalline nature. EPS-BMD26 showed moderate and concentration-dependent antioxidant potential recruiting different methods, including •OH, DPPH•, CUPRAC, and ABTS radical scavenging activities. Water-soluble EPS-BMD26 exhibited high water holding capacity of 190 ± 0.22% with a water solubility index of 60.6 ± 8.3%. At 1.25 mg mL-1, EPS-BMD26 inhibited biofilm formation of Staphylococcus aureus ATCC 25923 by 79.5%. Rheological characterization revealed that the aqueous solution of EPS-BMD26 had shear thinning and pseudoplastic behavior. Given these properties, EPS-BMD26 may be a promising bio-hydrocolloid, antibiofilm agent, and food additive for industrial applications. [ABSTRACT FROM AUTHOR]

Objective: Exopolysaccharide (EPS1-1) exhibits immunomodulatory and antitumor activities; however, its mechanism of action remains unknown. We determined the antitumor activity and whether EPS1-1 could enhance the shift of tumor-associated macrophages (TAMs) toward the M1 phenotype. Methods: The viability of MC-38 was assessed by the CCK-8 assay. The phagocytic activity of primary peritoneal macrophages (PEMs) was assayed by immunofluorescence microscopy and the levels of TNF-α, IL-6, and NO were tested by ELISA kits, and NO assay kit. M1 polarization was analyzed by flow cytometry and Immunofluorescence staining. Results and Discussion: The viability of MC-38 cells did not exhibit a significant difference (p > 0.05). EPS1-1 significantly upregulated IL-6, TNF-α, and NO production as well as phagocytic activity. Furthermore, it significantly inhibited tumor growth (85.32%), increased the spleen and thymus indices, and elevated the proportion of M1 cells in vitro and in vivo. Conclusions: It indicated that EPS1-1 had no direct inhibitory effect on MC-38 cell viability, exhibited remarkable anti-tumor activity against MC-38 transplanted tumors, reduced the volume of transplanted tumors, and significantly activated TAMs polarization to an immunostimulatory M1 phenotype to modulate antitumor immune responses in C57BL/6J mice. [ABSTRACT FROM AUTHOR]

Exopolysaccharides (EPSs) synthesized by probiotic bacteria have the potential to be used as food additives with health benefits. The goal of the present work was to investigate the production of EPSs by probiotic strains isolated from traditional dairy products in Kerman (Iran) and to characterize the produced EPS. The EPS production pattern was assessed by the pattern of bacterial growth as well as the effects of temperature and acidity changes on EPS production. To characterize the EPSs, FTIR spectroscopy was performed. The antibiofilm activity of the extracted EPS was evaluated by determining the pre- and post-adhesion treatments of EPS. Finally, the highest EPS-producing isolate was identified by molecular methods. Of the 15 selected isolates, the highest amount of EPS (0.53 g/L) was observed for the D-8 isolate. This isolate was identified as Enterococcus hirae strain D-8 by morphological, biochemical, and 16S rDNA gene sequencing analysis. The highest EPS production was observed at 30°C and pH 7.5 and started at the late logarithmic phase. FTIR analysis of the EPSs revealed diverse functional groups, including (O–H), (C–H), (C=O), and aldehyde groups. The results of this research showed that bacterial EPSs not only inhibited biofilm formation but also disrupted the established biofilms of some strains. These results highlight the importance of investigating strains that are able to produce EPS to deal with antibiotic resistance and biofilm disruption. [ABSTRACT FROM AUTHOR]

The present study investigates the low temperature tolerance strategies of thermophilic bacterium Anoxybacillus rupiensis TPH1, which grows optimally at 55 °C , by subjecting it to a temperature down-shift of 10 °C (45 °C) for 4 and 6 h followed by studying its growth, morphophysiological, molecular and proteomic responses. Results suggested that although TPH1 experienced increased growth inhibition, ROS production, protein oxidation and membrane disruption after 4 h of incubation at 45 °C yet maintained its DNA integrity and cellular structure through the increased expression of DNA damage repair and cell envelop synthesizing proteins and also progressively alleviated growth inhibition by 20% within two hours i.e., 6 h, by inducing the expression of antioxidative enzymes, production of unsaturated fatty acids, capsular and released exopolysaccharides and forming biofilm along with chemotaxis proteins. Conclusively, the adaptation of Anoxybacillus rupiensis TPH1 to lower temperature is mainly mediated by the synthesis of large numbers of defense proteins and exopolysaccharide rich biofilm formation. [ABSTRACT FROM AUTHOR]

In order to meet growing consumer demands in terms of naturalness, the pharmaceutical, food, and cosmetic industries are looking for active molecules of plant origin. In this context, hairy roots are considered a promising biotechnological system for the sustainable production of compounds of interest. Poplars (genus Populus, family Salicaceae) are trees of ecological interest in temperate alluvial forests and are also cultivated for their industrial timber. Poplar trees also produce specialized metabolites with a wide range of bioactive properties. The present study aimed to assess the hybrid poplar hairy root extracts for antimicrobial and antibiofilm activities against four main life-threatening strains of Gram-positive (Staphylococcus aureus, Bacillus subtilis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. Ethyl acetate extracts from two hairy root lines (HP15-3 and HP A4-12) showed significant antibacterial properties as confirmed by disc diffusion assay. Antibiofilm activities were found to be dose dependent with significant biofilm inhibition (75–95%) recorded at 1000 µg.mL−1 in all the bacterial strains tested. Dose-dependent enhancement in the release of exopolysaccharides was observed in response to treatment with extracts, possibly because of stress and bacterial cell death. Fluorescence microscopy confirmed loss of cell viability of treated bacterial cells concomitant with increased production of reactive oxygen species compared to the untreated control. Overall, this study demonstrates for the first time a high potential of poplar hairy root extracts as a natural and safe platform to produce antimicrobial agents in pharmaceutical, food, industrial water management, or cosmetic industries. [ABSTRACT FROM AUTHOR]

Bacterial exopolysaccharides (EPS) are an emerging class of biopolymers with extensive applications in different fields due to their versatile physico-chemical and biological properties. The role of EPS in healing of different wound types is gaining interest in the tissue engineering sector. Burn is one of the devitalizing injuries that causes greater physical harm and can be fatal. Appropriate treatment modalities have to be followed for faster healing outcomes and to minimize the risk. In this study, a bacterial EPS (EPS-H29) from the marine bacterium Halomonas malpeensis YU-PRIM-29 T was used to treat the burn wound in vivo. The biochemical and structural characterizations of EPS-H29 were carried out using standard methods. In addition, FE-SEM, conformational, rheological, and HP-GPC analyses were carried out. In vitro biocompatibility of EPS-H29 was studied in human dermal fibroblasts (HDFs) and keratinocytes (HaCaT). Scratch assay was used to study the wound healing in vitro. For in vivo evaluation, burn wound (second-degree) was created on Wistar albino rats and treated with EPS-H29 along with appropriate control groups. The total sugar and protein contents of EPS-H29 were 72.0 ± 1.4% and 4.0 ± 0.5%, respectively, with a molecular weight of 5.2 × 105 Da. The lyophilized samples exhibited porous surface features, and in solution, it showed triple helical conformation and shear thickening behavior. In vitro cell-based assays showed biocompatibility of EPS-H29 up to 200 μg/mL concentration. At a concentration up to 50 μg/mL, EPS-H29 promoted cell proliferation. Significant increase in the HDF cell migration was evident with EPS-H29 (15 μg/mL) treatment in vitro and induced significantly higher (p ≤ 0.0001) closure of the scratch area (90.3 ± 1.1%), compared to the control (84.3 ± 1.3%) at 24 h. Enhanced expression of Ki-67 was associated with the cell proliferative activities of EPS-H29. The animals treated with EPS-H29 showed improved healing of burn wounds with significantly higher wound contraction rate (80.6 ± 9.4%) compared to the positive control (54.6 ± 8.0%) and untreated group (49.2 ± 3.7%) with histopathological evidence of epidermal tissue formation at 15 days of treatment. These results demonstrate the biocompatibility and burn wound healing capability of EPS-H29 and its potential as an effective topical agent for the burn wound care. [ABSTRACT FROM AUTHOR]

Mushrooms of the genus Hericium spp. represent a series of delicious edible mushrooms with medicinal value. Here, for the first time, the species native to Iran, the mushroom Hericium coralloides, was collected in Mazandaran province, identified, and registered with the NCBI under accession number MW136052. The production of exopolysaccharides (EPS) in submerged culture was optimized using the response surface method. Among the physicochemical and culture medium conditions tested, rotation speed and concentration of maltose and peptone of soybean significantly affected the production of EPS. The proposed model predicts maximum EPS production (0.13 g/L) at 50 g/L maltose, 3 g/L soy peptone, and 1 g/L yeast extract, pH = 6.5, 200 rpm, inoculum at 5% v/v, and 22 °C. The molecular weight of the EPS chains was 413 and 1578 Da. EPS has antioxidant action (EC50 = 6.59 mg/mL) and cytotoxic activity against cancer cells. The viability of AGS and MKN-45 cancer cell lines declined to 20 and 30% after 48 h of the EPS treatment. H. coralloides EPS could be considered a natural dietary anti-cancer supplement. Further studies are necessary to understand the mechanism of the H. coralloides EPS activity on the cell cycle of cancer cells and to prove its action in vivo. [ABSTRACT FROM AUTHOR]

Green synthesis of nanoparticles is an effective, cost-effective, and environmentally friendly approach to produce biocompatible nanoparticles with broad-spectrum bioactivities. In the current study, lactic acid bacterium-derived exopolysaccharide (EPS) was explored to biologically synthesize green silver nanoparticles (EPS-AgNPs). The antibacterial and antioxidant activities of EPS-AgNPs were investigated by agar well diffusion and DPPH tests, respectively. Subsequently, EPS-AgNPs and chemical AgNPs were characterized, and their physicochemical properties were compared. According to 16 S rRNA gene sequencing, the EPS-producing lactic acid bacterium showed 97.77% similarity to Enterococcus faecium. EPS-AgNPs exhibited inhibitory effects on Gram-positive and Gram-negative bacterial pathogens. Additionally, EPS-AgNPs showed considerable ability (84%) to quench DPPH free radicals. Fourier-transform infrared spectroscopy (FT-IR) showed the involvement of EPS's functional groups, including hydroxyl, carbonyl, and aldehyde groups, in synthesizing nanoparticles. Scanning electron microscopy revealed a quasi-spherical morphology for both the EPS-AgNPs and chemically synthesized AgNPs, while X-ray diffraction (XRD) analysis confirmed their crystalline nature. The high metal content of chemical Ag-NPs (89.79%) was in good agreement with its high thermal stability in TGA results. Additionally, lower thermal stability and less Ag content (65.93%) of EPS-AgNPs, along with their smooth surfaces, indicated the capping role of EPS. EPS-AgNPs showed Z-average size, PI value, and zeta potential of 158.31 nm, 0.29, and − 17.75 mV, respectively. Collectively, the present study revealed that Enterococcus faecium-derived EPS acted as reducing, capping, and stabilizing agents in green synthesizing EPS-AgNPs with potential applications in medical and food-packaging industries. [ABSTRACT FROM AUTHOR]

This study aimed to determine the exopolysaccharide (EPS) production of Lactiplantibacillus pentosus KS27 depending on temperature, incubation time, and medium composition and to determine the optimum conditions. Characterization was carried out for the exopolysaccharide produced under optimum conditions. In the study, three different conditions (25 °C, 35 °C, 45 °C) were used for temperature, glycerol, and sucrose as media, and three different periods (24 h, 36 h, and 48 h) were used. It was determined that the solubility of EPS produced under optimal conditions had the highest water content (98 ± 0.01%), while the water binding capacity was also found to be as high as 1970 ± 0.01% and complied with common EPS characteristics. Differential scanning calorimeter analysis showed a gradual deterioration up to 191.88 °C and a slow decline up to 400 °C. FTIR analysis deciphered peak values between 3289 and 517 cm−1, and functional groups were detected. When the nuclear magnetic resonance (NMR) spectrum was examined, a heterogeneous structure appropriate to the structure of EPS was found by defining the peak entities in three separate regions. [ABSTRACT FROM AUTHOR]

Two alkaliphilic, Gram‐stain-negative bacterial strains (MEB004T and MEB108T) were isolated from water samples collected from Lonar lake, India. The phylogenetic analysis of their 16S rRNA gene sequences showed the highest similarity to A. delamerensis DSM 18314T (98.4%), followed by A. amylolytica DSM 18337T and A. collagenimarina JCM 14267T (97.9%). The genome sizes of strains MEB004T and MEB108T were determined to be 3,858,702 and 4,029,814 bp, respectively, with genomic DNA G + C contents of 51.4 and 51.9%. Average Nucleotide Identity, DNA–DNA Hybridization and Amino Acid Identity values between strains (MEB004T and MEB108T) and A. amylolytica DSM 18337T were (82.3 and 85.5), (25.0 and 29.2) and (86.7 and 90.2%). Both novel strains produced industrially important enzymes, such as amylase, lipase, cellulase, caseinase, and chitinase at pH 10 evidenced by the genomic presence of carbohydrate-active enzymes encoding genes. Genomic analyses further identified pH tolerance genes, affirming their adaptation to alkaline Lonar Lake. Dominant fatty acids were Summed feature 8 (C18:1ω7c and/or C18:1ω6c), C16:0, Summed feature 3, Sum In Feature 2 and C12:0 3OH. The prevalent polar lipids included phosphatidyl ethanolamine, phosphatidyl glycerol, and diphosphatidyl glycerol. The major respiratory quinone was ubiquinone-8. Based on the polyphasic data, we propose the classification of strains MEB004T and MEB108T as novel species within the genus Alkalimonas assigning the names Alkalimonas mucilaginosa sp. nov. and Alkalimonas cellulosilytica sp. nov., respectively. The type strains are MEB004T (= MCC 5208T = JCM 35954T = NCIMB 15460T) and MEB108T (= MCC 5330T = JCM 35955T = NCIMB 15461T). [ABSTRACT FROM AUTHOR]

Exopolysaccharides (EPS) are bioactive metabolites with high molecular weight and are produced by several microorganisms such as endophytic fungi. Thus, the aim of the present study was designed to explore the biosynthesis and characteristics of EPS by the endophytic fungus Neopestalotiopsis clavispora AUMC15969 and then investigate some environmental and nutritional factors that affect their production. Moreover, we estimated an additional value, namely the production of biodiesel. Maximum production of EPS was 7.86 g/L when N. clavispora was grown on lactose as the sole carbon source and peptone as the nitrogen source, respectively, and pH 7 at 35 °Cfor 10 days. The produced EPS had a total sugar content of 0.93 g/g where protein content was 0.076 g/g. It revealed a strong antioxidant activity that improved with increasing sample concentration, with the optimum concentration of 10 mg/mL producing 83.1% DPPH radical scavenging activity with an IC50 equal to 3.89 mg/mL. The extracted lipid from the fungal mycelia at the end of the fermentation process was 31.76% w/w. The biodiesel produced from the transesterification of lipids was 87.4% total fatty acid methyl esters. The present study demonstrated the potential production of EPS and lipid biopolymers in one-pot fermentation which could use as a resource for industrial technologies. [ABSTRACT FROM AUTHOR]

Exopolysaccharides or extracellular polymeric substances (EPS) has become an important resource and is being increasingly used in the biotechnology and biopharmaceutical industries. However, its production from glycerol under thermophilic conditions has not been reported. This study is aimed at isolating high-performance, EPS-producing bacteria under thermophilic conditions using glycerol as the substrate. Among the isolated microorganisms, Bacillus sonorensis strain NTV10 exhibited the highest EPS production. The optimum cultivation conditions in the enrichment medium (HS medium) were 1 g/L glycerol, 45 °C, and pH 7, with the highest EPS production of 15.97 mg/mL. We confirmed that NTV10 prefers thermophilic conditions for the highest EPS production. However, the utilization of glycerol was low because of the presence of yeast extracts and peptone in the HS medium. Therefore, the ability of glycerol conversion into EPS by NTV10 was evaluated using minimal medium (medium E*). We found that 15 g/L glycerol exhibited the highest EPS production (8.8 mg/mL). The monosaccharide composition of EPS from both media was similar, containing glucose, mannose, and rhamnose in a relative ratio of 5.1:2.2:1. The results of the IR spectrum showed the presence of mainly carboxyl and hydroxyl groups in the EPS product, which was in accordance with the monosaccharide composition. These properties can be applied in various industries such as food processing, cosmetics, and pharmaceuticals. The experimental knowledge derived from this study can be used to promote the use of glycerol as a renewable substrate for bioconversion into highly valuable products, such as EPS production. [ABSTRACT FROM AUTHOR]

Pullulan is a biopolymer produced by various strains of the fungi Aureobasidium pullulans. It is made up of maltotriose units consisting of α-(1,6) and α-(1,4) glycosidic bonds. Pullulan was discovered by Bauer in 1938, characterized by Bernier in 1958 and named as 'pullulan' by Bender in 1959. Submerged fermentation is widely employed for pullulan production followed by downstream processing for recovery of pullulan. Factors such as nutrients, minerals, pH, temperature, surfactants, light intensity, and melanin intermediate affect its production. Various optimization methods such as Plackett Burman design, response surface methodology, and artificial neural networks have been utilised for enhancing the yield of pullulan. Pullulan yield as high as 62.52 g/L can be achieved using a 5 L fermenter under optimised conditions. It can be characterized by techniques such as nuclear magnetic resonance, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy. The biopolymer has remarkable properties which makes it an ideal candidate to be used in various applications such as the biomedical and pharmaceutical sectors, cosmetics, food, and wastewater treatment. Pullulan's applications can be expanded by chemically modifying to obtain grafted pullulan, polymer blends, nanocomposites and hydrogels which have been gaining importance in recent years. Over the years, many patents using pullulan have been granted for different applications worldwide. This review sheds light on all these aspects of pullulan including its future scope. [ABSTRACT FROM AUTHOR]

The widespread occurrence of phytopathogenic fungi causes significant crop losses and poses a challenge for agricultural sustainability. Traditional fungicides are often harmful to the environment and human health, necessitating the search for safer, more effective alternatives. Previous studies have shown that metal nanoparticles have potential antifungal properties, but their stability and biocompatibility remain concerns. The exopolysaccharide (EPS) produced by Azotobacter chroococcum XH2018 offers a biocompatible matrix that could stabilize these nanoparticles and enhance their antifungal efficacy. The EPS, consisting of 73.3% glucose, 26.6% galactose, and 0.1% mannose (molar ratio of Glu:Gal:Man 0.407:0.147:0.0005) was used as a stabilizing dielectric matrix and nanocarrier for the electrochemically synthesized Cu/Cu2O-NPs. Before impregnation, Cu/Cu2O-NPs consisted of 27.2% Cu-NPs and 72.8% Cu2O-NPs. After impregnation, this ratio changed to 73.7% Cu-NPs and 26.3% Cu2O-NPs. This evidence suggests that Cu2O-NPs are actively reduced in the presence of the EPS matrix, first of all because of the glucose monomer in the polysaccharide macromolecule. EPS of A. chroococcum XH2018 donates electrons to copper (I)-oxide, leading to the reduction of copper (I)-oxide to copper metal. As-biofabricated Cu/Cu2O-NPs strongly limited the formation of fungal conidia. Low concentrations of Cu/Cu2O-NPs reduced the conidia formation of Fusarium solani and Fusarium oxysporum f.sp. vasinfectum up to 85–90%, Rhizoctania solani up to 95%, and Alternaria alternata up to 80%. [ABSTRACT FROM AUTHOR]

Objective: Colanic acid (CA) is a promising and actively studied polysaccharide, which geroprotective and stimulating properties have already been described in animal models. Different protocols are used to isolate and purify CA in research, some of which may result in contamination with proteins, DNA, and other polysaccharides. Methods: In order to effectively further investigate the biological properties of CA, we developed 5 protocols for CA isolation, differed in cultivation condition, protein precipitation, and polysaccharide precipitants. Results and Discussion: We found that the most suitable protocol for CA isolation includes protein removal with trichloroacetic acid and polysaccharide precipitation with ethanol (95%, 3 volumes). Conclusions: Such a simple protocol will serve to standardize CA studies and can be applied to obtain large volumes of polysaccharide. [ABSTRACT FROM AUTHOR]

In this study, EPS production conditions of Geobacillus thermodenitrificans HBB 111, a thermophilic microorganism, were optimized and the amount of produced EPS (EPS 111) was found to be 44.0 mg/L. EPS 111 was purified using ion exchange chromatography and gel filtration chromatography, and a single type of exopolysaccharide was obtained. The structure of the purified EPS 111 was evaluated by TLC, FTIR, NMR, and GC–MS, and it was observed that it contained hexose (glucose, fructose, galactose and mannose) and pentose sugars. From the SEM photographs, it was understood that EPS 111 had an amorphous, rough, and layered structure. It was found that purified EPS 111 had low cytotoxicity (2.3%) and exhibited high antioxidant activity and remarkable antidiabetic, prebiotic and fibrinolytic activities. It is very valuable that the purified EPS 111 in this study offers multiple biological activities compared to the thermophilic EPSs reported in the literature and has a high potential for use in biotechnological and biomedical fields. [ABSTRACT FROM AUTHOR]

The genus Erwinia includes plant-pathogenic, non-pathogenic and even opportunistic human pathogens. Among them, Erwinia amylovora is one of the most studied species, as the etiological agent of the relevant necrotic plant disease fire blight. Its most important pathogenicity factor is amylovoran, an exopolysaccharide essential in the formation of a protective biofilm used by the bacterium to escape the plant protection mechanisms. Amylovoran biosynthesis, regulation and secretion require the concerted action of twelve genes clustered in a region spanning 16 kb, the ams operon. Most of the encoded proteins build and polymerize the repeating oligosaccharide units of galactose, glucose, glucuronic acid and pyruvate, others have signalling, regulation and secretion functions. We compared the ams operon organisation, predicted 3D structure of the encoded proteins of Erwinia amylovora in eighteen Erwinia species. We detected the presence of a paralog (for the amsG gene) and some rearrangements in the EPS biosynthetic operon in specific taxa that could be connected to the species-specific pathogenicity profile. The present study adds fundamental information about the genomic determinants of exopolysaccharide secretion in the Erwinia genus, and clarifies the evolutionary relationships among the genes in the ams operon. [ABSTRACT FROM AUTHOR]

Biodegradable nanocarriers based on polysaccharide-derived amphiphilic copolymers are promising candidates to enhance drug solubility and stability. This study aimed to design a novel amphiphilic carrier based on enzymatic polymerization-derived exopolysaccharides, α-1,3-glucan. Glycosyltransferase I from Streptococcus mutans was used to synthesize α-1,3-glucan, and the amphiphilic α-1,3-glucan-graft-poly(ε-caprolactone) (Glucan-g-PCL) copolymer was synthesized via a homogeneous ring-opening polymerization (ROP) in ionic liquid, 1-butyl-3-methylimidazolium chloride. The chemical structures and physical properties of Glucan-g-PCL copolymer were characterized by FT-IR, 1H NMR, XRD, and TGA. The self-assembly behavior of the amphiphilic α-1,3-glucan derivative was investigated by fluorescence probe. The results showed that Glucan-g-PCL exhibited a low critical aggregation concentration (CAC) and formed core-shell structured nanostructure via self-assembly. Quercetin (Qu), a hydrophobic active component, was successfully encapsulated within the Glucan-g-PCL micelle-like nanostructure, showing efficient encapsulation and dispersion in water. Qu/Glucan-g-PCL micelle-like nanostructure (Qu/M) was characterized by DLS, TEM, FT-IR, and XRD. FT-IR and XRD analyses showed that Qu was present in an amorphous state in the formulation and without any chemical reactions during the sample preparation procedures. In addition, the antioxidant properties of the Qu/M were investigated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, and significantly improved antioxidant activity was observed for Qu/M compared to Qu/water. The utilization of Glucan-g-PCL nanostructure encapsulation opens up new possibilities for enhancing and expanding the practical applications of quercetin and α-1,3-glucan. [ABSTRACT FROM AUTHOR]

The current study assessed the levels of exopolysaccharides (EPS) and indole-3-acetic acid (IAA) and the impacts of halophilic bacteria Oceanobacillus oncorhynchi W4 under Cr (VI). The effects of W4 were tested for its ability to remove Cr (VI) at several concentrations, the removal rate was reached after 48 h at 58.4%, 53.3%, 49.2%, and 43.1%). After 12–48 h, the maximum removal rate of 29–58% was found at an initial concentration of 50 mg/L (Cr (VI)). The Box–Behnken design based on response surface methodology was utilized to optimize the EPS, including pH, sucrose concentration, and incubation period. The highest EPS yield (314.5 mg/L) was obtained under 96 h at pH 7.0, with 5% sucrose concentration. The strain Oceanobacillus oncorhynchi W4 was tested for its ability to create EPS at various concentrations of Cr (VI). After 96 h, it generated the maximum amount of EPS (216.3 mg/L) at a concentration of 50 mg/L. By using FT-IR spectrum measurements, it was confirmed that hexavalent chromium and EPS had surface chemical interactions. At various Cr (VI) concentrations, the isolate W4 was tested for its ability to secrete Indole-3 acetic acid. IAA secretion (control) without Cr (VI) achieved a maximum of 1.45 mg/ml at 120 h. At 200 mg/L Cr (VI) concentration, 1.65 mg/ml of IAA was also produced after 48 h. According to the findings, Oceanobacillus oncorhynchi W4 was a promising isolate in a stressful environment. [ABSTRACT FROM AUTHOR]

Drought stress is a significant environmental challenge affecting global agriculture, leading to substantial reductions in crop yields and overall plant productivity. It induces a cascade of physiological and biochemical changes in plants, including reduced water uptake, stomatal closure, and alterations in hormonal balance, all of which contribute to impaired growth and development. Drought stress diminishes crop production by impacting crucial plant metabolic pathways. Plants possess the ability to activate or deactivate specific sets of genes, leading to changes in their physiological and morphological characteristics. This adaptive response enables plants to evade, endure, or prevent the effects of drought stress. Drought stress triggers the activation of various genes, transcription factors, and signal transduction pathways in plants. In this context, imposing plant growth-promoting rhizobacteria (PGPR) emerges as a promising strategy. PGPR, employing diverse mechanisms such as osmotic adjustments, antioxidant activity, and phytohormone production, not only ensures the plant's survival during drought conditions but also enhances its overall growth. This comprehensive review delves into the various mechanisms through which PGPR enhances drought stress resistance, offering a thorough exploration of recent molecular and omics-based approaches to unravel the role of drought-responsive genes. The manuscript encompasses a detailed mechanistic analysis, along with the development of PGPR-based drought stress management in plants. [ABSTRACT FROM AUTHOR]

In our present study, the evaluation was done on immunostimulatory activity of the exopolysaccharide (EPS) derived from a marine actinobacterium, Streptomyces sp. SRT21. The average molecular weight (Mw) of purified SRT21-EPS was estimated to be 2.86 × 105 Da. NMR analysis demonstrated the incidence of α-(1–3) glycosidic linkage of glucose and frequency of mannose with α-(1–6) glycosidic linkage. The structural pattern of SRT21-EPS was peaked in the range of 22.8° and 43.5° at 2θ in XRD, while the ZP value was detected as −11.7 mV. The thermal behaviour of SRT21-EPS was characterized by DTA and TGA. In SEM, the morphology of SRT21-EPS were observed as irregular, branchy and flake-based polymeric matrix. With optimal dosage, SRT21-EPS promoted the cell proliferation, Nitric oxide (NO) levels induction, phagocytosis index and ROS production in macrophage cells. As a result, the key pro-inflammatory cytokines secretion, IκB-α degradation and nuclear localization of p65 was accomplished through TLR receptor/NF-κB signaling. [ABSTRACT FROM AUTHOR]

Heavy metal accumulation is one of the major agronomic challenges that has seriously threatened food safety. As a result, metal-induced phytotoxicity concerns require quick and urgent action to retain and maintain the physiological activities of microorganisms, the nitrogen pool of soils, and the continuous yields of wheat in a constantly worsening environment. The current study was conducted to evaluate the plant growth-promoting endophytic Aspergillus flavus AUMC 16,068 and its EPS for improvement of plant growth, phytoremediation capacity, and physiological consequences on wheat plants (Triticum aestivum) under lead stress. After 60 days of planting, the heading stage of wheat plants, data on growth metrics, physiological properties, minerals content, and lead content in wheat root, shoot, and grains were recorded. Results evoked that lead pollution reduced wheat plants' physiological traits as well as growth at all lead stress concentrations; however, inoculation with lead tolerant endophytic A. flavus AUMC 16,068 and its respective EPS alleviated the detrimental impact of lead on the plants and promoted the growth and physiological characteristics of wheat in lead-contaminated conditions and also lowering oxidative stress through decreasing (CAT, POD, and MDA), in contrast to plants growing in the un-inoculated lead polluted dealings. In conclusion, endophytic A. flavus AUMC 16,068 spores and its EPS are regarded as eco-friendly, safe, and powerful inducers of wheat plants versus contamination with heavy metals, with a view of protecting plant, soil, and human health. [ABSTRACT FROM AUTHOR]

Spider silk is a promising material with great potential in biomedical applications due to its incredible mechanical properties and resistance to degradation of commercially available bacterial strains. However, little is known about the bacterial communities that may inhabit spider webs and how these microorganisms interact with spider silk. In this study, we exposed two exopolysaccharide-secreting bacteria, isolated from webs of an orb spider, to major ampullate (MA) silk from host spiders. The naturally occurring lipid and glycoprotein surface layers of MA silk were experimentally removed to further probe the interaction between bacteria and silk. Extensibility of major ampullate silk produced by Triconephila clavata that was exposed to either Microbacterium sp. or Novosphigobium sp. was significantly higher than that of silk that was not exposed to bacteria (differed by 58.7%). This strain-enhancing effect was not observed when the lipid and glycoprotein surface layers of MA silks were removed. The presence of exopolysaccharides was detected through NMR from MA silks exposed to these two bacteria but not from those without exposure. Here we report for the first time that exopolysaccharide-secreting bacteria inhabiting spider webs can enhance extensibility of host MA silks and silk surface layers play a vital role in mediating such effects. [ABSTRACT FROM AUTHOR]

Fermented eggplant is a traditional fermented food, however lactic acid bacteria capable of producing exopolysaccharide (EPS) have not yet been exploited. The present study focused on the production and protective effects against oxidative stress of an EPS produced by Lacticaseibacillus paracasei NC4 (NC4-EPS), in addition to deciphering its genomic features and EPS biosynthesis pathway. Among 54 isolates tested, strain NC4 showed the highest EPS yield and antioxidant activity. The maximum EPS production (2.04 ± 0.11 g/L) was achieved by culturing in MRS medium containing 60 g/L sucrose at 37 °C for 48 h. Under 2 mM H2O2 stress, the survival of a yeast model Saccharomyces cerevisiae treated with 0.4 mg/mL NC4-EPS was 2.4-fold better than non-treated cells, which was in agreement with the catalase and superoxide dismutase activities measured from cell lysates. The complete genome of NC4 composed of a circular chromosome of 2,888,896 bp and 3 circular plasmids. The NC4 genome comprises more genes with annotated function in nitrogen metabolism, phosphorus metabolism, cell division and cell cycle, and iron acquisition and metabolism as compared to other reported L. paracasei. Of note, the eps gene cluster is not conserved across L. paracasei. Pathways of sugar metabolism for EPS biosynthesis were proposed for the first time, in which gdp pathway only present in few plant-derived bacteria was identified. These findings shed new light on the cell-protective activity and biosynthesis of EPS produced by L. paracasei, paving the way for future efforts to enhance yield and tailor-made EPS production for food and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

As one of the most promising groups of microbes, lactic acid bacteria (LAB) can synthesize metabolites that can be used in different industries over the world, mainly in the pharmaceutical, food, and dairy industries. In this study, a novel exopolysaccharide was extracted and isolated from the probiotic strain Lactobacillus reuteri B2, and assessed on biological activity and its possible application as a biosorbent for the removal of Ni2+ ions from contaminated water. New exopolysaccharide was characterized using FTIR, SEM, XRD, NMR, MALDI-TOF MS, and TGA/DTG analysis. Biological assays included antioxidative activity, cytotoxic assay, and adhesion assay of L. reuteri B2 to HT29 cells. Our hypothesis was that if this exopolysaccharide is nontoxic, it can be used as a novel biomaterial for the possible application of the removal of Ni2+ ions from contaminated water. The scavenging effect of nontoxic exopolysaccharide was 76% at 2 mg/mL using ABTS assay, in biological assays, while the removal efficiency of nickel from the aqueous solution was 92.96% in biosorption study. According to these results, this exopolysaccharide can be considered a very promising biomaterial for potential application in different industries, from pharmacy to wastewater treatments. [ABSTRACT FROM AUTHOR]

Aspartyl dipeptidase (dipeptidase E) can hydrolyze Asp-X dipeptides (where X is any amino acid), and the enzyme plays a key role in the degradation of peptides as nutrient sources. Dipeptidase E remains uncharacterized in Streptomyces. Orf2 from Streptomyces sp. 139 is located in the exopolysaccharide biosynthesis gene cluster, which may be a novel dipeptidase E with "S134-H170-D198" catalytic triad by sequence and structure comparison. Herein, recombinant Orf2 was expressed in E. coli and characterized dipeptidase E activity using the Asp-ρNA substrate. The optimal pH and temperature for Orf2 are 7.5 and 40 ℃; Vmax and Km of Orf2 are 0.0787 mM·min−1 and 1.709 mM, respectively. Orf2 exhibits significant degradation activities to Asp-Gly-Gly, Asp-Leu, Asp-His, and isoAsp-Leu and minimal activities to Asp-Pro and Asp-Ala. Orf2 contains a Ser-His-Asp catalytic triad characterized by point mutation. In addition, the Asp147 residue of Orf2 is also proven to be critical for the enzyme's activity through molecular docking and point mutation. Transcriptome analysis reveals the upregulation of genes associated with ribosomes, amino acid biosynthesis, and aminoacyl-tRNA biosynthesis in the orf2 mutant strain. Compared with the orf2 mutant strain and WT, the yield of crude polysaccharide does not change significantly. However, crude polysaccharides from the orf2 mutant strain exhibit a wider range of molecular weight distribution. The results indicate that the Orf2 links nutrient stress to secondary metabolism as a novel dipeptidase E. Key points: • A novel dipeptidase E with a Ser-His-Asp catalytic triad was characterized from Streptomyces sp. 139. • Orf2 was involved in peptide metabolism both in vitro and in vivo. • Orf2 linked nutrient stress to mycelia formation and secondary metabolism in Streptomyces. [ABSTRACT FROM AUTHOR]

There is a great scientific curiosity to discover all environments sheltering microalgae, especially those with exceptional characteristics from coldest to hottest ones, the purpose remains to explore the potential of the native microalgae flora and the research for new bioactive compounds. This study aimed to isolate a polysaccharide-producing microalga from an extreme ecosystem and to evaluate its capacity to inhibit the α-d-glucosidase enzyme. Chlorella strain is isolated from hypersaline Lake in the Algerian desert. The exopolysaccharide extraction was performed by the concentration of free-cell supernatant in a rotary evaporator. The infrared analysis showed a characteristic footprint of carbohydrates with particular functional groups, such as sulfate. Gas chromatography–mass spectrometry has revealed a hetero-exopolysaccharide composed of galactose 35.75%, glucose 21.13%, xylose 16.81%, fructose 6.96%, arabinose 5.10%, and glucuronic acid 2.68%. The evaluation of the anti-hyperglycemic activity demonstrated a significant α-d-glucosidase inhibition of 80.94 ± 0.01% at 10 mg mL−1 with IC50 equal to 4.31 ± 0.20 mg mL−1. This study opens a vast prospect to use exopolysaccharides as natural nutraceutical or food additive. [ABSTRACT FROM AUTHOR]

This study focused on optimizing the fermentation-based production of Exopolysaccharides (EPS) from Enterococcus faecium F58 initially isolated from traditional Moroccan Jben, a fresh goat cheese. Using the central composite design, yeast extract, MnSO4, and time affect EPS concentration. The highest experimental and predicted EPS production yields were 2.46 g/L ± 0.38 and 2.86 g/L, respectively. Optimal concentrations of yeast extract (4.46 g/L) and MnSO4 (0.011 g/L) were identified after 26 h at 30 °C. Characterization of EPS was conducted using SEM with EDX, XRD, and FTIR analyses. These tests revealed a specific morphology and an amorphous structure. Additionally, thermogravimetric analysis indicated adequate EPS stability up to 200 °C with anti-adhesion properties against different pathogens. This study offers valuable insights into the optimized production of EPS from Enterococcus faecium F58, which exhibits significant structural and functional properties for various applications in the food and biotechnology industries. [ABSTRACT FROM AUTHOR]

It was tested the production of a viscous exopolysaccharide (EPS) by Lelliottia amnigena using different concentrations (10, 15, 25, 50 and 100%) of produced water (PW) and Dialyzed PW (DPW) at 100% concentration, with a nutrient medium based on glycerin and sucrose as carbon sources in 44 h batches. There was an increase in EPS recovery when used PW up to a concentration of 25%. The viscosity of the EPS solutions was maintained with DPW and up to 15% of PW, such a condition resulted in 9.34 gL− 1 of EPS, representing an increase of 84.9% compared to the control (P < 0.0001). The PW 15% increased the viscosity per produced liter by 114.3% (P < 0.0001). Scanning electron microscopy and Energy-dispersive X-ray spectroscopy analysis showed that EPS adsorbed mineral constituents of the substrate and its characterization by Fourier Transform Infrared Spectroscopy was similar to an external control of a commercial EPS produced by an Enterobacter A47 strain. PW at 15% becomes an alternative to increase the EPS production process and can contribute to the mitigation of environmental damage through sustainable PW management in the oilfield chain. [ABSTRACT FROM AUTHOR]

Lactic acid been the most widespread bacteria extensively used in food industry. Functional lactic acid bacteria have been extensively studied for widespread beneficial properties in food industry. The exopolysaccharides (EPS) from Pediococcus acidilactici BCB1H studied for physiochemical and microbiological effects as well as the functional properties of the yogurt. This work indicated that addition of BCB1H-EPS improved microrheological properties of yogurt during fermentation. Further quality improvement of yogurt during twenty-one days of cold was also observed, including decreased post acidification, increased viable bacterial counts, and improved water holding capacity, texture characteristics and antioxidant activity of yogurt. Untargeted metabolomics analysis by UPLC-QTOF MS revealed, 72 differential metabolites affected by BCB1H-EPS, including amino acids, nucleotides, organic acids, etc., which were found to be involved mainly in citrate cycle, metabolism of d-glutamate and d-glutamine, biosynthesis of tyrosine, phenylalanine, and tryptophan. These changes of metabolisms provided more energy for the metabolism of EPS, and positively affected physical, functional, and nutritional properties of yogurt. The results indicated that the BCB1H-EPS important roles and applications in functional dairy products with higher additional value. [ABSTRACT FROM AUTHOR]

Nowadays, exopolysaccharides (EPS) produced from bacterial cells are manufactured for their use in different industries in the world, mainly in the food, pharmaceutical, and wastewater industries. The characteristics of EPS, such as being biodegradable, safe, high adsorption capacity, and reusable, make them significant and potential applications in the purification of contaminated water of heavy metals. In this study, the possible application in biosorption Ni2+ ions from contaminated water was assessed using this exopolysaccharide as a biosorbent. The new exopolysaccharide from the bacterial strain K. oxytoca J7 was extracted, isolated, and characterized using SEM, FTIR, XRD, TGA/DTG, and MALDI-TOF MS analysis. Likewise, the cytotoxic activity was performed for EPS from K. oxytoca J7 strain. The aim of this study was to investigate the possible application of non-toxic exopolysaccharide in the purification of contaminated water by removing Ni2+ ions. The results obtained from the biosorption study showed that the Langmuir model is well suited to describe the adsorption process of Ni2+ ions by EPS from K. oxytoca J7, with a maximum adsorption capacity of 269.97 mg g–1. The importance of this study is the possible use of natural nontoxic exopolysaccharide extracted from the pathogen microorganism, K. oxytoca J7, for the removal of Ni2+ ions from the contaminated water. [ABSTRACT FROM AUTHOR]

The present study aimed at developing an exopolysaccharide based nanoemulsion with increased kinetic stability, solubility, and availability. The nanoformulation was fabricated employing ultrasonication, a high energy fabrication method and constituted of flaxseed oil, tween 80, ethanol, and exopolysaccharide (extracted from Ganoderma gibbosum). The resultant formulation was found to have an average droplet size of 101.5 nm, with a PDI of 0.189, and a zeta potential of -8.2 mV. The particle size was further confirmed via the high resolution transmission electron microscopy which reported the nanoemulsion droplets to be round, uniform in size, with particle size ranging between 10 to 115 nm. In terms of the thermodynamic and storage stability the formulation was found to be highly stable and resistant to creaming, phase separation, and changes in pH. Further, the results in-vivo antioxidant assay revealed an increase in the activity of serum superoxide dismutase and catalase and a decrease in the serum level of thiobarbituric acid reactive substances suggesting that the formulation is capable of ameliorating the effect of reactive oxygen species in biological system. [ABSTRACT FROM AUTHOR]

This study investigates the antibacterial activity of exopolysaccharides (EPS) produced by the marine bacterium Bacillus halotolerans against clinical strains of Pseudomonas aeruginosa and Serratia marcescens. EPS production was optimized by exploring different carbon sources with glucose, peptone, and calcium chloride identified as significant factors for enhanced production. The optimized medium achieved a production rate of 0.612 g/L, surpassing the unoptimized medium's production of 0.556 g/L. The EPS exhibited noteworthy hydroxyl scavenging activity and demonstrated hydrogen-donating ability by scavenging DPPH radicals. Fourier-transform infrared spectroscopy analysis revealed characteristic peaks representing hydroxyl and carboxyl groups, glycosidic linkages, and sulfate groups within the EPS structure. Nuclear magnetic resonance analysis confirmed the complex and heterogeneous nature of the EPS, with glucose and galactose residues and the presence of polysaccharides identified. Monomer units of the EPS structure were identified as glucose and galactose, and a prominent peak at 7.942 min indicated the presence of beta-1,5-O-Dibenzoyl-ribofuranose. This study provides valuable insights into optimizing EPS production, characterizing its properties, and evaluating its antibacterial activity against Pseudomonas sp. strains. Further investigations are necessary to explore the potential applications and underlying mechanisms of these antibacterial EPS, contributing to advancements in microbiology and biotechnology. [ABSTRACT FROM AUTHOR]

The exopolysaccharides (EPSs) of lactic acid bacteria (LAB) have presented various bioactivities and beneficial characteristics, rendering their vast commercial value and attracting a broad interest of researchers. The diversity of EPS structures contributes to the changes of EPS functions. However, the low yield of EPS of LAB has severely limited these biopolymers' comprehensive studies and applications in different areas, such as functional food, health and medicine fields. The clarification of biosynthesis mechanism of EPS will accelerate the synthesis and reconstruction of EPS. In recent years, with the development of new genetic manipulation techniques, there has been significant progress in the EPS biosynthesis mechanisms in LAB. In this review, the structure of LAB-derived EPSs, the EPS biosynthesis basic pathways in LAB, the EPS biosynthetic gene cluster, and the regulation mechanism of EPS biosynthesis will be summarized. It will focus on the latest progress in EPS biosynthesis regulation of LAB and provide prospects for future related developments. [ABSTRACT FROM AUTHOR]

Microorganisms produce a diverse group of biomolecules having amphipathic nature (amphiphiles). Microbial amphiphiles, including amyloids, bio-surfactants, and other exo-polymeric substances, play a crucial role in various biological processes and have gained significant attention recently. Although diverse in biochemical composition, these amphiphiles have been reported for common microbial traits like biofilm formation and pathogenicity due to their ability to act as surface active agents with active interfacial properties essential for microbes to grow in various niches. This enables microbes to reduce surface tension, emulsification, dispersion, and attachment at the interface. In this report, the ecological importance and biotechnological usage of important amphiphiles have been discussed. The low molecular weight amphiphiles like biosurfactants, siderophores, and peptides showing helical and antimicrobial activities have been extensively reported for their ability to work as quorum-sensing mediators. While high molecular weight amphiphiles make up amyloid fibers, exopolysaccharides, liposomes, or magnetosomes have been shown to have a significant influence in deciding microbial physiology and survival. In this report, we have discussed the functional similarities and biochemical variations of several amphipathic biomolecules produced by microbes, and the present report shows these amphiphiles showing polyphyletic and ecophysiological groups of microorganisms and hence can 'be replaced in biotechnological applications depending on the compatibility of the processes. [ABSTRACT FROM AUTHOR]

Purpose: The modification of clay minerals by exopolysaccharides (EPS) may significantly increase their adsorption capacity for heavy metals. Therefore, this study focused on the characterization of two typical clay minerals, montmorillonite, and kaolinite modified with EPS (produced by Rhizobium tropici), their impact on the adsorption of uranium, U(VI), and the influence of pH, sulfate, and phosphate. Materials and methods: The characterization of clays, EPS, and clay-EPS composites were carried out using X-ray power diffraction (XRD), fourier transform infrared spectroscopy (FTIR), atomic force microscope (AFM), and scanning electron microscopy (SEM)/energy dispersive X-ray (EDX) analysis. Results: Results showed that EPS partially entered and dehydrated cations in the interlayers of montmorillonite, resulting in the decrease in interlayer d-spacing, which were confirmed by XRD and FTIR. Montmorillonite had better EPS adsorption capacity than kaolinite. The EPS-clay mineral composites significantly increased U(VI) adsorption capacity by 650% and 60% for montmorillonite and kaolinite, respectively. The adsorption capacity for U(VI) was ordered as montmorillonite-EPS > EPS > montmorillonite > kaolinite-EPS > kaolinite. Montmorillonite-EPS modification for U(VI) was maximized at pH 4, while the high pH such as pH 9 inhibited the U(VI) adsorption. Sulfate or phosphate has a negligible effect on the adsorption of UO22+ on montmorillonite-EPS. Conclusion: The current study provides a new insight for the application of biopolymers in remediation of U(VI) contaminated area. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study aimed to production, optimization, and characterization of an exopolysaccharide (EPS) by Bacillus coagulans IBRC-M10807. The maximum EPS production (234.21 ± 4.83 mg/L) was obtained under optimal incubation temperature 54.95 °C, incubation time 31.36 h, initial pH 5.73, casein peptone concentration 3.93%, and lactose concentration 1.33%. The monosaccharide compositions of EPS were mannose, rhamnose, glucose, and galactose, with an average molecular weight of 4.22 × 105 Da. Differential scanning calorimetry and thermogravimetric analysis showed that the EPS had high thermal stability with a melting point of 262.5 °C and degradation temperature of 276.29 °C. DPPH radical scavenging, hydroxyl radical scavenging, and reducing power of EPS were 85.25% ± 0.55%, 80.08% ± 0.31%, and 0.824 ± 0.008 at 2 mg/mL concentration, respectively. These results indicated that the EPS produced by B. coagulans IBRC-M10807 could be a promising candidate for use as a safe and natural antioxidant as well as a functional ingredient in the pharmacy and food industry. [ABSTRACT FROM AUTHOR]

The optimization of culture conditions for the production of bioactive exopolysaccharide (EPS) by Ganoderma gibbosum, employing response surface methodology has been carried out in the present study. Initially, Plackett–Burman design was applied to identify different factors affecting the EPS yield and among these factors FeSO4, almond oil and glucose were found to be the most significant. The interaction between these factors was analyzed using a central composite design which predicted the optimum values for FeSO4, almond oil, and glucose to be 0.635 g/L, 2.286%, and 30.05 g/L, respectively. The determined (R2) value was 0.9848 which indicated that the model was in a good agreement with the experimental results. In order to validate the conditions subsequent verification experiment was also carried out, as there was no significant difference between the predicted value (3.36 g/L) and actual value (3.41 g/L), the model was considered to be a good fit for EPS production. The EPS produced was further evaluated for its anti-oxidant potential. The in-vitro results suggested that the EPS exhibited remarkable scavenging properties on 2, 2-diphenylpicrylhydrazyl (DPPH) and 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) ions at a dosage of 1 mg/mL suggesting potent anti-oxidant activity. [ABSTRACT FROM AUTHOR]

Background: Exopolysaccharides are extremely powerful molecules with a wide range of uses in pharmaceuticals due to their structural and compositional complexity. Marine microorganisms often produce bioactive substances with novel functions and structures because of their special living conditions. Polysaccharides from marine microorganisms are of interest to new drug discovery. Results: The current research focused on the isolation of bacteria from Red Sea, Egypt, that have the ability to produce a new natural exopolysaccharide in order to be examined in treating Alzheimer's illness to obviate side effects of synthetic drugs. Properties of exopolysaccharide (EPS) produced by an isolated Streptomyces strain were investigated for its capability to play as anti-Alzheimer. This strain was identified morphologically, physiologically, and biochemically and actually was confirmed by molecularly 16S rRNA analysis as Streptomyces sp. NRCG4 with accession number MK850242. The produced EPS was fractionated by precipitation 1:4 volumes of chilled ethanol and the third major fraction (1:3) listed as NRCG4, and then the functional groups, MW, and chemical evaluation have been detected via Fourier-transform infrared (FTIR), high-performance gel permeation chromatography (HPGPC), and high-performance liquid chromatography (HPLC). The findings showed that NRCG4 was an acidic EPS composed of mannuronic acid, glucose, mannose, and rhamnose in a molar ratio of 1.2:1.5:2.8:1.0, respectively. NRCG4 Mw was determined to be 4.25 × 105 gmol−1 and the Mn to be 1.97 × 105 gmol−1. Also, the NRCG4 included uronic acid (16.0%) and sulfate (0.0%), but no protein was found. In addition, antioxidant and anti-inflammation activity was measured through various methods. This study confirmed that NRCG4 exopolysaccharide exerted anti-Alzheimer's characters via inhibition of cholinesterase and tyrosinase as well as anti-inflammatory and antioxidant abilities. Additionally, it occurred a potential role in the suppression of Alzheimer's disease risk factors through its antioxidant (metal chelation, radical scavenging capability), anti-tyrosinase and anti-inflammatory characteristics. The anti-Alzheimer's disease efficacy of NRCG4 exopolysaccharide may be assigned to its unique determined chemical composition. Conclusions: The present study highlighted those exopolysaccharides could be harnessed to improve pharmaceutical industry (anti-Alzheimer, anti-tyrosinase, anti-inflammatory, and antioxidant agents). [ABSTRACT FROM AUTHOR]

Microbial exopolysaccharides, especially from thermophiles, are gaining attention due to their thermostability and reduced viscosity at elevated temperatures which make them suitable candidates for pharmaceutical, cosmetics and food industries. This study aims to identify potential of a novel thermophile for the production of high amounts of exopolysaccharide. It also reports suitable process parameters for growth of novel thermophile in exopolysaccharide production medium and determination of optimum glucose concentration as its production generally requires high amount of glucose making the process cost intensive. Thermophilic bacteria, from a local hot spring, were screened for the production of exopolysaccharide, and growth kinetics of the best producer, Brevibacillus borstelensis MK878423, was studied. The growth study of bacterium revealed optimum time of production as 40 h, and maximum product was formed at 30 g/l glucose. The logistic growth curve of the bacterium was analysed, and kinetic rate constants for substrate utilization were estimated by modified Luedeking-Piret kinetic model. The specific growth rate of the bacterium was calculated to be 0.0166 h−1 with kinetic rate constants as − 18.953 (α) and 90.655 (β) for Luedeking-Piret substrate. This is the first report on the production of exopolysaccharide by a strain of Brevibacillus borstelensis. Understanding the kinetic rate constants for substrate consumption will help in extrapolating the system of microbial exopolysaccharide production from agricultural wastes with high glucose content. The determination of optimal glucose concentration will also help in utilizing biowastes as substrates for exopolysaccharide production following biorefinery concept as wastes are utilized for the production of value-added chemicals. [ABSTRACT FROM AUTHOR]

Exopolysaccharides (EPSs) are naturally occurring high-molecular-weight carbohydrates that have been widely studied for their biological activities, including antioxidant, immunomodulatory, anticancer and gut microbiota regulation activities. Polysaccharides are abundant in nature and can be derived from animals, plants, algae, and microorganisms, but among polysaccharides with potential uses, EPSs from microorganisms have the advantages of a short production cycle, high yield, and independence of production from season and climate and thus have broad prospects. While the safety of the producing microorganism can represent a problem in application of microbial EPSs, lactic acid bacteria (LAB) have been used by humans for thousands of years, and they and their products are generally recognized as safe. This makes LAB excellent sources for exopolysaccharides. EPS-producing LAB are readily found in nature. Through screening of strains, optimization of culture conditions, and improvement of the growth medium, the yield of EPSs from LAB can be increased and the scope of application broadened. This review summarizes EPSs from LAB in terms of structure, function and applications, as well as yield optimization, and introduces recent research on the biological activities and practical applications of LAB EPSs, aiming to provide references for researchers in related areas. [ABSTRACT FROM AUTHOR]

Exopolysaccharides (EPSs) are polysaccharides produced by microbes in the form of slime or as a capsular material. Their chemical composition and structure lend themselves to fine-tuned properties and the possibility of metabolic engineering and applications in various industries. Among the archaebacteria, halophiles are a group of bacteria that are well known to produce EPS for forming biofilm so that they can withstand adverse conditions like salinity and osmotic pressure. In this work, seven bacterial strains were isolated from the Ennore Salt pan, and the highest EPS-producing strain SSVRVG7 (Paenibacillus alvei) identified by 16s rRNA sequencing showed highest antibacterial activity. The physicochemical parameters that have an effect on EPS production for the isolate SSVRVG7—carbon source (fructose), cheaper carbon source (glucose), nitrogen source (peptone), NaCl concentration (15%), and pH (8)—were optimized to enhance the EPS production and the EPS produced was characterized using ultra violet-visible spectroscopy, Fourier transfer infrared spectroscopy, thin layer chromatography, scanning electron microscopy (SEM), and proton nuclear magnetic resonance. The antibacterial activity of the strain showed the highest activity against S. faecalis. The characterized EPS was then applied for nanofiber synthesis by electrospinning at different polymer concentrations. The produced electrospun fibers were characterized morphologically by SEM. [ABSTRACT FROM AUTHOR]

The selenium nanoparticles (SeNPs) linked with exopolysaccharide (EPS) of E. faecium MC-5 were successfully produced. UV–Vis spectra, DLS, zeta potential, SEM, TEM, FT-IR, thermogravimetric analysis-DSC, and X-ray diffraction measurements were used to characterize the SeNPs in terms of formation, size, stability, and functional group attachment, morphology, distribution, and phase. The spectral resonance of SeNPs was validated by seeing a peak at 383 nm in UV-Vis, demonstrating their synthesis. The SeNPs conjugated to EPS were found to be amorphous and well distributed in the size range of 76 nm. The interactions between the –OH groups of EPS and SeNPs have resulted in new C–O–Se bonds and excellent SeNP scattering distribution in the EPS matrix. The SeNPs were found to have good thermal stability (a strong resistance to thermal processes over 245 °C). The SeNPs displayed good antimicrobial properties with different pathogens at various concentrations. This work not only reveals the critical role of EPS as a biocompatible polymer template for SeNP dispersion, stability, and size control but also acts as an effective antioxidant against DPPH, and hydroxyl radicals and also showed better antibiofilm properties. SeNPs also had a greater survival rate of up to 100 μg/mL in the in vivo study and had no cytotoxicity on larvae of Artemia salina. Hence, the potential SeNPs act as a unique contender to tackle the biofilm challenge in aquaculture sectors and can be implemented in the medical and cosmetic industries. [ABSTRACT FROM AUTHOR]

Objective: Its eps gene cluster, the antioxidant activity and monosaccharide composition of exopolysaccharides, the expression levels of related genes at different fermentations were analyzed for clarifying the exopolysaccharide biosynthesis mechanism of Lactobacillus delbrueckii subsp. bulgaricus LDB-C1. Results: The comparison analysis of eps gene clusters indicated that the gene clusters present diversity and strain specificity. The crude exopolysaccharides from LDB-C1 exhibited a good antioxidant activity. Compared with glucose, fructose, galactose, and fructooligosaccharide, inulin significantly improved the exopolysaccharide biosynthesis. The structures of EPSs were significantly different under different carbohydrate fermentation conditions. Inulin obviously increased the expressions of most EPS biosynthesis related genes at fermentation 4 h. Conclusion: Inulin accelerated the beginning of the exopolysaccharide production in LDB-C1, and the enzymes promoted by inulin was beneficial for the accumulation of exopolysaccharide at the whole fermentation process. [ABSTRACT FROM AUTHOR]

Biofilm formation and resistance to antibiotics in pathogenic bacteria are important concerns in the treatment of infectious diseases. A new rapid, eco-friendly and cost-effective strategy to overcome these problems is the use of microbial exopolysaccharides (EPS) for green synthesis of various metal nanoparticles (NPs). This study used EPS from a native probiotic Lactobacillus isolate to synthesize silver nanoparticles (AgNPs) with effective antimicrobial, antibiofilm and antioxidant properties. AgNPs were synthesized by 10 mg of EPS of Lactobacillus paracasei (L. paracasei MN809528) isolated from a local yogurt. The characteristics of EPS AgNPs were confirmed using UV–VIS, FT-IR, DLS, XRD, EDX, FE-SEM, and zeta potential. Antimicrobial, antibiofilm and antioxidant activities of EPS AgNPs were evaluated by the agar well diffusion, microtiter dilution, SEM electron microscopy, and DPPH radical absorption methods, respectively. Spectroscopy data indicated the presence of a 466-nm peak as a feature of AgNPs. FT-IR confirmed the presence of biological agents in the synthesis of AgNPs. FE-SEM results showed that the synthesized AgNPs had a spherical shape with the size of 33–38 nm. Synthesized AgNPs at a concentration of 100 mg/ml demonstrated a significant inhibitory activity compared to chemically synthesized AgNPs. These NPs, exhibited the greatest effect of inhibiting the Escherichia coli and Pseudomonas aeruginosa biofilm formation at sub-MIC concentration, and the best effect of DPPH radical as antioxidant activity was determined at 50-μg/ml concentration. Our findings reveal that EPS AgNPs synthesized by the native isolate of L. paracasei (MN809528) is an inexpensive and environment-friendly candidate for application in pharmaceuticals fields. [ABSTRACT FROM AUTHOR]

Probiotic-derived exopolysaccharides are considered as promising sources of carbohydrate with extensive applications in many industries. In the current study, yeast strains were isolated from chicken ingluvies and gizzard samples. According to molecular identification, EPS-producing yeast (Pichia sp. DU2) showed the most similarity to Pichia cactophila (99.67%). Pichia sp. DU2 showed probiotic properties. EPS of Pichia sp. DU2 showed emulsifying activity. The formed emulsions showed 53% (colza oil) and 100% (p-xylene) stability after 24 h. These emulsions were oil-in-water and have stability in the presence of NaCl, KCl, and also acidic and basic conditions. Also, the EPS showed anti-biofilm (29.7–47.6% and 19.06–55.26% against B. cereus and Y. enterocolitica, respectively) and flocculating activities (31.4%). FT-IR showed the presence of various functional groups in EPS structure. Also, its heteropolysaccharide nature was revealed in 1H-NMR and HPLC analysis. This emulsifying EPS showed significant thermal stability and negative zeta potential, which make it a promising carbohydrate for various industries. Finally, according to the predicted model, the maximal EPS production was achieved at reaction time 36 h, pH 6, yeast extract concentration 1.0%, and sucrose concentration 5%. Pichia sp. DU2 with probiotic properties and producing EPS with emulsifying, anti-biofilm, and flocculating activities can be considered as promising yeast strain in various industries like food and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Mushrooms possess wide array of biologically active secondary metabolites and have been traditionally used for their medicinal properties. Exopolysaccharide (EPS) is one of such bioactive metabolites. The bioactive attributes and emulsification capabilities of the exopolysaccharides produced by a novel brown-rot fungus Fomitopsis meliae AGDP-2 under submerged fermentation has been thoroughly investigated in the present study. Exopolysaccharide displayed anti-oxidant activities in dose dependent manner with the maximum scavenging of ABTS radicals (42.45%), DPPH radicals (75.34%), Hydroxyl radicals (63.64%), Superoxide anion radical (76.54%) and Ferric Reducing Antioxidant Power with IC50 value of 231 µg/mL. Additionally, evaluation of anti-proliferative properties revealed that EPS significantly inhibited the proliferation of HepG2 and HT-29 cancer cells followed by moderate inhibition of HeLa and MCF-7 cancer cell lines and quite less inhibition of L-132 and KB cell lines. The IC50 values of EPS for the abovementioned cell lines are 9.465 µg/mL, 11.25 µg/mL, 38.98 µg/mL, 87.78 µg/mL, 2061 µg/mL and 2361 µg/mL respectively. Moreover EPS also possess good anti-microbial as well as anti-biofilm properties. The studies on emulsification potential described that EPS is good emulsifier of different vegetable oils and the emulsion formed was quite stable up to 144 h. [ABSTRACT FROM AUTHOR]

A biocidal level of hydrogen peroxide (H2O2), far beyond the natural level, is widely used to control bloom-forming cyanobacteria in freshwater. The extracellular polymeric substance of these cyanobacteria is a key factor in determining the applied H2O2 dosage. The exopolysaccharide (EPS) in the extracellular polymer shows H2O2 scavenging capability. However, the scavenging capabilities of EPSs from other cyanobacteria against biocidal levels of H2O2 as well as their protective roles against cyanobacterial cells are not well known. In this study, we used four nonbloom-forming cyanobacteria as target organisms, two with rich EPS envelopes (EPS-rich strains) and two with thin EPS envelopes (EPS-thin strains), to assess the roles of EPS. It was found that the two EPS-rich strains were much more tolerant to a high dose of exogenous H2O2 than the two EPS-thin strains. The EPSs extracted from the four strains exhibited similar but rapid H2O2 scavenging activity. Additionally, the EPSs from the EPS-rich strains could improve the tolerance of the EPS-thin strains to H2O2 stress, implying potentially nonselective protection against oxidative stress. In addition, all the cell lysates of the four strains showed H2O2 decomposition ability, with the efficiency being slightly different between the two types of strains. This study suggests that cyanobacterial EPS plays a generally crucial role against external strong oxidative stress and may provide a useful reference for the application of H2O2 in environmental management. [ABSTRACT FROM AUTHOR]

Exopolysaccharide (EPS)-producing Bifidobacterium bifidum EPS DA-LAIM was isolated from healthy human feces, the structure of purified EPS from the strain was analyzed, and its prebiotic activity was evaluated. The EPS from B. bifidum EPS DA-LAIM is a glucomannan-type heteropolysaccharide with a molecular weight of 407–1007 kDa, and its structure comprises 2-mannosyl, 6-mannosyl, and 2,6-mannosyl residues. The purified EPS promoted the growth of representative lactic acid bacteria and bifidobacterial strains. Bifidobacterium bifidum EPS DA-LAIM increased nitric oxide production in RAW 264.7 macrophage cells, indicating its immunostimulatory activity. Bifidobacterium bifidum EPS DA-LAIM also exhibited high gastrointestinal tract tolerance, gut adhesion ability, and antioxidant activity. These results suggest that EPS from B. bifidum EPS DA-LAIM is a potentially useful prebiotic material, and B. bifidum EPS DA-LAIM could be applied as a probiotic candidate. [ABSTRACT FROM AUTHOR]