Purification, characterization and antitumor activity of an exopolysaccharide produced by Bacillus velezensis SN-1

A glucomannan produced by Bacillus velezensis HY23 and its growth promoting effect on soybeans under salt stress

The Bacillus genus is widely distributed in nature, has bacteriostatic and growth-promoting activities, and has broad application potential in agriculture. An exopolysaccharide (EPS) was extracted and purified from Bacillus velezensis HY23. Structural characterisation of the EPS was performed by chemical and spectroscopic analyses. Methylation analysis showed that the EPS of HY23 was composed of mannose and glucose at a ratio of 82:18 and was identified as glucomannan. Combined with the nuclear magnetic resonance (NMR) analysis, EPS from HY23 had a backbone of →2)-α-D-Manp-(1 → and →2,6)-α-D-Manp-(1 → branched at C-6 with terminal α-(3-O-Me)-D-Manp-(1 → and →6)-α-D-Manp-(1 → residues as the side chain. A certain amount of β-D-Glcp residues were also present in backbone. Moreover, EPS significantly improved the nitrogen-fixing activity and salt resistance of soybean seedlings by regulating the antioxidant pool and expression of ion transporters. These findings indicate that EPS from B. velezensis HY23 is a potential biostimulant for enhancing plant resistance to salt stress.

Characterization and biological activities of a novel exopolysaccharide produced from Geobacillus thermodenitrificans HBB 111 strain

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.

Microbial exopolysaccharides: Unveiling the pharmacological aspects for therapeutic advancements

Microbial exopolysaccharides (EPSs) have emerged as a fascinating area of research in the field of pharmacology due to their diverse and potent biological activities. This review paper aims to provide a comprehensive overview of the pharmacological properties exhibited by EPSs, shedding light on their potential applications in various therapeutic areas. The review begins by introducing EPSs, exploring their various sources, significance in microbial growth and survival, and their applications across different industries. Subsequently, a thorough examination of the pharmaceutical properties of microbial EPSs unveils their antioxidant, immunomodulatory, antimicrobial, antidepressant, antidiabetic, antiviral, antihyperlipidemic, hepatoprotective, anti-inflammatory, and anticancer activities. Mechanistic insights into how different EPSs exert these therapeutic effects have also been discussed in this review. The review also provides comprehensive information about the monosaccharide composition, backbone, branches, glycosidic bonds, and molecular weight of pharmacologically active EPSs from various microbial sources. Furthermore, the factors that can affect the pharmacological activities of EPSs and approaches to improve the EPSs' pharmacological activity have also been discussed. In conclusion, this review illuminates the immense pharmaceutical promise of microbial EPS as versatile bioactive compounds with wide-ranging therapeutic applications. By elucidating their structural features, biological activities, and potential applications, this review aims to catalyze further research and development efforts in leveraging the pharmaceutical potential of microbial EPS for the advancement of human health and well-being, while also contributing to sustainable and environmentally friendly practices in the pharmaceutical industry.

Highly active probiotic hydrogels matrixed on bacterial EPS accelerate wound healing via maintaining stable skin microbiota and reducing inflammation

Skin microbiota plays an important role in wound healing, but skin injuries are highly susceptible to wound infections, leading to disruption of the skin microbiota. However, conventional antibacterial hydrogels eliminate both probiotics and pathogenic bacteria, disrupting the balance of the skin microbiota. Therefore, it is important to develop a wound dressing that can fend off foreign pathogenic bacteria while preserving skin microbiota stability. Inspired by live bacteria therapy, we designed a probiotic hydrogel (HAEPS@L.sei gel) with high viability for promoting wound healing. Lactobacillus paracasei TYM202 encapsulated in the hydrogel has the activity of promoting wound healing, and the hydrogel matrix EPS-M76 has the prebiotic activity that promotes the proliferation and metabolism of Lactobacillus paracasei TYM202. During the wound healing process, HAEPS@L.sei gel releases lactic acid and acetic acid to resist the growth of pathogenic bacteria while maintaining Firmicutes and Proteobacteria balance at the phylum level, thus preserving skin microbiota stability. Our results showed that live probiotic hydrogels reduce the incidence of inflammation during wound healing while promoting angiogenesis and increasing collagen deposition. This study provides new ideas for developing wound dressings predicated on live bacterial hydrogels.

Physicochemical Characterization, Antioxidant and Anticancer Activity Evaluation of an Acidic Polysaccharide from Alpinia officinarum Hance

AHP-3a, a triple-helix acidic polysaccharide isolated from Alpinia officinarum Hance, was evaluated for its anticancer and antioxidant activities. The physicochemical properties and structure of AHP-3a were investigated through gel permeation chromatography, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. The weight-average molecular weight of AHP-3a was 484 kDa, with the molar percentages of GalA, Gal, Ara, Xyl, Rha, Glc, GlcA, and Fuc being 35.4%, 21.4%, 16.9%, 11.8%, 8.9%, 3.1%, 2.0%, and 0.5%, respectively. Based on the results of the monosaccharide composition analysis, methylation analysis, and NMR spectroscopy, the main chain of AHP-3a was presumed to consist of (1→4)-α-D-GalpA and (1→2)-α-L-Rhap residues, which is a pectic polysaccharide with homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) structural domains containing side chains. In addition, the results of the antioxidant activity assay revealed that the ability of AHP-3a to scavenge DPPH, ABTS, and OH free radicals increased with an increase in its concentration. Moreover, according to the results from the EdU, wound healing, and Transwell assays, AHP-3a can control the proliferation, migration, and invasion of HepG2 and Huh7 hepatocellular carcinoma cells without causing any damage to healthy cells. Thus, AHP-3a may be a natural antioxidant and anticancer component.

Therapeutic Potential of Bacteroides fragilis SNBF-1 as a Next-Generation Probiotic: In Vitro Efficacy in Lipid and Carbohydrate Metabolism and Antioxidant Activity

This study explores the potential of aerotolerant Bacteroides fragilis (B. fragilis) strains as next-generation probiotics (NGPs), focusing on their adaptability in the gastrointestinal environment, safety profile, and probiotic functions. From 23 healthy infant fecal samples, we successfully isolated 56 beneficial B. fragilis strains. Notably, the SNBF-1 strain demonstrated superior cholesterol removal efficiency in HepG2 cells, outshining all other strains by achieving a remarkable reduction in cholesterol by 55.38 ± 2.26%. Comprehensive genotype and phenotype analyses were conducted, including sugar utilization and antibiotic sensitivity tests, leading to the development of an optimized growth medium for SNBF-1. SNBF-1 also demonstrated robust and consistent antioxidant activity, particularly in cell-free extracts, as evidenced by an average oxygen radical absorbance capacity value of 1.061 and a 2,2-diphenyl-1-picrylhydrazyl scavenging ability of 94.53 ± 7.31%. The regulation of carbohydrate metabolism by SNBF-1 was assessed in the insulin-resistant HepG2 cell line. In enzyme inhibition assays, SNBF-1 showed significant α-amylase and α-glucosidase inhibition, with rates of 87.04 ± 2.03% and 37.82 ± 1.36%, respectively. Furthermore, the cell-free supernatant (CFS) of SNBF-1 enhanced glucose consumption and glycogen synthesis in insulin-resistant HepG2 cells, indicating improved cellular energy metabolism. This was consistent with the observation that the CFS of SNBF-1 increased the proliferation of HepG2 cells by 123.77 ± 0.82% compared to that of the control. Overall, this research significantly enhances our understanding of NGPs and their potential therapeutic applications in modulating the gut microbiome.

Structural, rheological properties and antioxidant activities analysis of the exopolysaccharide produced by Rhizobium leguminosarum bv. viciae VF39

Microbial exopolysaccharide is an eco-friendly and non-toxic biopolymeric materials widely used in various industrial fields such as pharmaceutical, food and cosmetics based on its structural, rheological and physiochemical properties. A microbial exopolysaccharide (VF39-EPS) was directly isolated from Rhizobium leguminosarum bv. viciae VF39. Structural analysis using FTIR and 2D NMR spectroscopy confirmed the complete chemical structures of VF39-EPS as 3-hydroxybutanoylglycan with octasaccharide repeating units containing two pyruvyl, two acetyl, and one 3-hydroxybutanoyl group. VF39-EPS exhibited thermal stability up to 275 °C and showed characteristic rheological behaviors of structural fluid with weak gel-like properties above 4 % the aqueous solution, suggesting VF39-EPS as a potential effective thickener or hydrogel scaffolder. Flow behavior tests validated broad stability at a wide range of both pHs from 2 to 12 and temperatures from 25 to 75 °C, and even in the presence of various salts. Furthermore, VF39-EPS showed excellent antioxidant effects of 78.5 and 62.4 % (n = 3, p < 0.001) in DPPH scavenging activity and hydroxyl radical scavenging activity, respectively. Therefore, those structural, rheological and antioxidant properties suggest that VF39-EPS could be one of the excellent biomaterial candidates for cosmetic, food and pharmaceutical industries based on its characteristic rheological behaviors in various condition and excellent antioxidant activity.

Structural properties and biological activities of the extracellular polysaccharide of Bacillus subtilis LZ13-4

The remarkable functional characteristics of Bacillus subtilis extracellular polysaccharides (BSPS) are of great interest. Therefore, in the present study, BSPS was isolated and characterized to obtain two fractions, BSPS-1 and BSPS-2, respectively, and to investigate their biological activities. BSPS-1 contained fructose, glucose, and galactose (molar ratio: 25.27:43.37:31.36), while BSPS-2 contained fructose with only trace amounts of glucose, galactose, and mannose (molar ratio: 55.08:19.03:19.21:6.68), and their respective average molecular weights were 16.9 kDa and 202.67 kDa. With a 93.55 % clearance of ABTS•+ at a concentration of 2 mg/mL of BSPS-1, the antioxidant activity revealed that BSPS-1 had greater antioxidant activity than BSPS-2 and that both were concentration-dependent. The inhibitory effect on HepG2 cells demonstrated that BSPS-1 and BSPS-2 significantly inhibited the proliferation of HepG2 and increased the expression of apoptotic proteins, causing apoptosis. The inhibition rate on HepG2 cells was dose-dependent and reached 52.7 % and 40.3 % after 48 h of action. BSPS-2 and 800 μg/mL BSPS-1 growth was inhibited in the G1/G0 phase, while 200 and 400 μg/mL BSPS-1 growth was inhibited in the S phase. In conclusion, the study of the BSPS's structure and properties can offer a theoretical foundation for real-world industrial applications.

Exopolysaccharides produced by Bacillus spp. inhibit biofilm formation by Staphylococcus aureus strains associated with bovine mastitis

Bovine mastitis is a costly disease in the dairy sector worldwide. Here the objective was to identify and characterize anti-biofilm compounds produced by Bacillus spp. against S. aureus associated with bovine mastitis. Results showed that cell-free supernatants of three Bacillus strains (out of 33 analysed) reduced S. aureus biofilm formation by approximately 40 % without affecting bacterial growth. The anti-biofilm activity was associated with exopolysaccharides (EPS) secreted by Bacillus spp. The EPS decreased S. aureus biofilm formation in a dose-dependent manner, inhibiting biofilm formation by 83 % at 1 mg/mL. The EPS also showed some biofilm disruption activity (up to 36.4 %), which may be partially mediated by increased expression of the aur gene. The characterization of EPS produced by Bacillus velezensis 87 and B. velezensis TR47II revealed macromolecules with molecular weights of 31.2 and 33.7 kDa, respectively. These macromolecules were composed mainly of glucose (mean = 218.5 μg/mg) and mannose (mean = 241.5 μg/mg) and had similar functional groups (pyranose ring, beta-type glycosidic linkage, and alkynes) as revealed by FT-IR. In conclusion, this study shows the potential applications of EPS produced by B. velezensis as an anti-biofilm compound that could contribute to the treatment of bovine mastitis caused by S. aureus.

Optimization and purification of bioproducts from Bacillus velezensis PhCL fermentation and their potential on industrial application and bioremediation

Bioproduction is considered a promising alternative way of obtaining useful and green chemicals. However, the downstream process of biomolecules has been one of the major difficulties in upscaling the application of bioproducts due to the high purification cost. Acid precipitation is the most common method for purifying biosurfactants from the fermentation broth with high purity. However, the use of strong acids and organic solvents in solvent extraction has limited its application. Hence, in this study, a new strain of Bacillus velezensis PhCL was isolated from phenolic waste, and its production of amylase had been optimized via response surface methodology. After that, amylase and biosurfactant were purified by sequential ammonium sulfate precipitation and the result suggested that even though the purified crude biosurfactant had a lower purification fold compared to the acid precipitation, the yield was higher and both enzymes and biosurfactant also could be recovered for lowering the purification cost. Moreover, the purified amylase and crude biosurfactant were characterized and the results suggested that the purified crude biosurfactant would have a higher emulsion activity and petroleum hydrocarbon removal rate compared to traditional surfactants. This study provided another approach for purifying bioactive compounds including enzymes and biosurfactants from the same fermentation broth and further explored the potential of the crude purified biosurfactant in the bioremediation of polycyclic aromatic hydrocarbons and petroleum hydrocarbons.

Evaluation of antioxidation, regulation of glycolipid metabolism and potential as food additives of exopolysaccharide from Sporidiobolus pararoseus PFY-Z1

At present, there are relatively few studies on the production of exopolysaccharide (EPS) by yeasts. Therefore, exploring the properties of EPS produced by yeast can not only enrich the source of EPS, but also play an important role in its future application in the food field. The aim of this study was to explore the biological activities of EPS (named SPZ) from Sporidiobolus pararoseus PFY-Z1, as well as the dynamic changes in physical and chemical properties that occur during simulated gastrointestinal digestion, and the effects of SPZ on microbial metabolites during fecal fermentation in vitro. The results revealed that SPZ had good water solubility index, water-holding capacity, emulsifying ability, coagulated skim milk, antioxidant properties, hypoglycemic activities, and bile acid-binding abilities. Furthermore, the content of reducing sugars increased from 1.20 ± 0.03 to 3.34 ± 0.11 mg/mL after gastrointestinal digestion, and had little effect on antioxidant activities. Moreover, SPZ could promote the production of short-chain fatty acids during fermentation for 48 h, in particular, propionic acid and n-butyric acid increased to 1.89 ± 0.08 and 0.82 ± 0.04 mmol/L, respectively. Besides this, SPZ could inhibit LPS production. In general, this study can help us to better understand the potential bioactivities, and the changes in bio-activities of compounds after digestion of SPZ.

Exopolysaccharide from Lactococcus hircilactis CH4 and Lactobacillus delbrueckii GRIPUMSK as new therapeutics to treat biofilm pathogens, oxidative stress and human colon adenocarcinoma

Naturally occurring biopolymers like exopolysaccharides (EPS) secreted by lactic acid bacteria (LAB) has gained significant attention as they are cost effective, renewable and safe. In order to prevent the rapid increase in antibiotic resistant bacteria, the EPS of LAB offers novel approach of targeting the antibiotic resistant pathogens by limiting their effects on environment. Accordingly, in this study, the production, purification, characterization and biological properties of exopolysaccharides from Lactococcus hircilactis strain CH4 and Lactobacillus delbrueckii strain GRIPUMSK were performed. The optimization of lactic acid bacterial strains for exopolysaccharide production was done by response surface methodology and changing the carbon sources in the growth media. The carbohydrate and protein of exopolysaccharide 1 were 79.7 % and 8.7 % respectively and exopolysaccharide 2 were 75.2 % and 9.3 % respectively. When compared with the commercial emulsifier sodium dodecyl sulfate, both the exopolysaccharides have shown good emulsifying activity. Both the exopolysaccharides were linear homo-polysaccharide as determined by Fourier transform infrared spectroscopy and Nuclear magnetic resonance spectra. Scanning electron microscopy showed that the exopolysaccharides were porous and capable of holding water. The exopolysaccharides were partially crystalline as confirmed by X-ray diffraction spectra. Exopolysaccharides from L. hircilactis and L. delbrueckii exhibited significant antimicrobial activity against H. pylori, S. flexneri, S. pyogenes, E. faecalis and C. albicans. Both the exopolysaccharides revealed significant 2,2-diphenyl-1-picrylhydrazyl and hydrogen peroxide scavenging ability with the IC50 value of 100 μg/ml and 80 μg/ml respectively. Exopolysaccharides from L. hircilactis and L. delbrueckii at 100 μg/ml showed significant anticancer activity on HT-29 cells with 58.4 % and 58.7 % respectively. These findings proved that exopolysaccharides from the two selected lactic acid bacterial strains could be explored as natural bioactive carbohydrate polymer for biomedical applications.

Structural characterization and hepatoprotective activity of exopolysaccharide from Bacillus velezensis SN-1

BACKGROUND

Exopolysaccharide biopolymers produced by microorganisms are crucial to the environment. They contribute to areas such as the health and bionanotechnology sectors, food and cosmetic industries as gelling agents, and environmental sector as flocculants owing to their biodegradability and non-toxic nature. The current study aimed to isolate the fraction of released exopolysaccharide (rEPS) by Bacillus velezensis SN-1 from Chinese Da-Jiang.

RESULTS

The weighted average molecular weight of the major isolated component, rEPS-2, was 202 kDa, and its monosaccharide composition included mannose, glucose, and galactose at a molar ratio of 0.38:0.30:0.32. Further, the rEPS-2 was characterized using methylation analysis and one-dimensional/two-dimensional nuclear magnetic resonance (1D/2D NMR) spectroscopy. In vivo hepatoprotective effects indicated that rEPS-2 could alleviate carbon tetrachloride (CCl₄ )-induced liver injury in mice by lowering the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and the malondialdehyde (MDA) levels. Furthermore, rEPS-2 can increase the expression of antioxidant genes HO-1, GCLC and NQO1 in the Nrf2/ARE signaling pathway, thereby increasing the activity of antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and reduced catalase (CAT) in liver cells. Furthermore, the rEPS-2 can be used and modulate the gut microbiota of mice with liver injury caused by CCl₄ .

CONCLUSIONS

These results suggest that rEPS-2 has promising potential to serve as hepatoprotective agents. © 2022 Society of Chemical Industry.

Effect of fermentation pH on the structure, rheological properties, and antioxidant activities of exopolysaccharides produced by Alteromonas australica QD

The pH value was essential for the growth and metabolism of microorganisms. Acidic pH exopolysaccharide (AC-EPS) and alkaline pH exopolysaccharide (AL-EPS) secreted by A. australica QD mediated by pH were studied in this paper. The total carbohydrate content and molecular weight of AC-EPS (79.59% ± 2.24% (w/w), 8.374 × 10⁵ Da) and AL-EPS (82.48% ± 1.46% (w/w), 6.182 × 10⁵ Da) were estimated and compared. In AC-EPS, mannose (3.78%) and galactose (3.24%) content was more, while the proportion of glucuronic acid was less in comparison to AL-EPS. The scanning electron microscopy revealed the structural differences among the AC-EPS and AL-EPS. Thermogravimetric analysis showed degradation temperatures of 272.8 °C and 244.9 °C for AC-EPS and AL-EPS, respectively. AC-EPS was found to exhibit better rheological properties and emulsifying capabilities, while AL-EPS had superior antioxidant activities. Overall, both AC-EPS and AL-EPS have the potential to be used as emulsifiers and biological antioxidants.

Isolation of a New Polysaccharide from Dandelion Leaves and Evaluation of Its Antioxidant, Antibacterial, and Anticancer Activities

Dandelion, in China, has a long history as a medicinal and edible plant, and possesses high nutritional and medical value. The present study aimed to isolate a new polysaccharide (DLP-3) from dandelion leaves and to evaluate its antioxidant, antibacterial, and anticancer activities. The structure of DLP-3 was analyzed using HPLC, FT-IR, SEM, GC-MS, and NMR spectroscopy. DLP-3 mainly consisted of Man, Rha, GlcA, Glc, Gal, and Ara with molar ratios of 2.32, 0.87, 1.21, 3.84, 1.00, and 1.05, respectively, with a molecular weight of 43.2 kDa. The main linkages of DLP-3 contained (1→4)-α-d-Glc, (1→4,6)-α-d-Glc, (1→6)-α-d-Gal, (1→2)-α-d-Man, (1→4)-α-d-Man, β-l-Ara-(1→, and α-l-Rha-(1→. DLP-3 exhibited a smooth surface, purely flake-like structure, and a triple helix conformation. Moreover, DLP-3 presented obvious antioxidant and antibacterial activities in a concentration-dependent manner. DLP-3 showed significant anticancer activities by inhibiting tumor cell proliferation. These findings provide a theoretical basis for the application of DLP-3 as a natural functional active substance in functional foods.

Potential Applications of an Exopolysaccharide Produced by Bacillus xiamenensis RT6 Isolated from an Acidic Environment

The Bacillus xiamenensis RT6 strain was isolated and identified by morphological, biochemical and molecular tests from an extreme acidic environment, Rio Tinto (Huelva). Optimisation tests for exopolysaccharide (EPS) production in different culture media determined that the best medium was a minimal medium with glucose as the only carbon source. The exopolymer (EPS_t) produced by the strain was isolated and characterised using different techniques (GC-MS, HPLC/MSMS, ATR-FTIR, TGA, DSC). The molecular weight of EPS_t was estimated. The results showed that the average molecular weight of EPS_t was approximately 2.71 × 10⁴ Da and was made up of a heteropolysaccharide composed of glucose (60%), mannose (20%) and galactose (20%). The EPS_t showed antioxidant capabilities that significantly improved cell viability. Metal chelation determined that EPS_t could reduce the concentration of transition metals such as iron at the highest concentrations tested. Finally, the emulsification study showed that EPS_t was able to emulsify different natural polysaccharide oils, reaching up to an 80% efficiency (olive and sesame oil), and was a good candidate for the substitution of the most polluting emulsifiers. The EPS_t was found to be suitable for pharmaceutical and industrial applications.

Exopolysaccharides from Marine Microbes: Source, Structure and Application

The unique living environment of marine microorganisms endows them with the potential to produce novel chemical compounds with various biological activities. Among them, the exopolysaccharides produced by marine microbes are an important factor for them to survive in these extreme environments. Up to now, exopolysaccharides from marine microbes, especially from extremophiles, have attracted more and more attention due to their structural complexity, biodegradability, biological activities, and biocompatibility. With the development of culture and separation methods, an increasing number of novel exopolysaccharides are being found and investigated. Here, the source, structure and biological activities of exopolysaccharides, as well as their potential applications in environmental restoration fields of the last decade are summarized, indicating the commercial potential of these versatile EPS in different areas, such as food, cosmetic, and biomedical industries, and also in environmental remediation.

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

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

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

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

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Both EPSs has high thermal stability.

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EPS exhibited appreciable antibacterial and antioxidant activity.

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

Preparation, chemical structure, and immunostimulatory activity of a water-soluble heteropolysaccharide from Suillus granulatus fruiting bodies

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A water-soluble heteropolysaccharide (SGP2-1) was purified from Suillus granulatus.

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SGP2-1with Mw of 150.75 kDa had the (1 → 4)-α-Glcp backbone structure.

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SGP2-1 could be recognized by toll-like receptor 2 in RAW 264.7 macrophages.

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SGP2-1 enhanced pinocytic capacity and promoted ROS, NO, and cytokine production.

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SGP2-1 exerted immunoregulatory activity through MAPKs, PI3K/Akt and NF-κB pathways.

A water-soluble heteropolysaccharide (SGP2-1) was purified from Suillus granulatus fruiting bodies by anion-exchange chromatography and gel permeation chromatography. The structural characteristics were analyzed by high-performance gel permeation chromatography, high-performance liquid chromatography, Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy. The immunostimulatory activity was investigated using RAW 264.7 macrophages. Results showed that SGP2-1 with weight average molecular weight of 150.75 kDa was composed of mannose, glucose, and xylose. The backbone of SGP2-1 was mainly composed of → 4)-α-Glcp-(1→, and the terminal group α-d-Glcp → was linked to the main chain by O-6 position. SGP2-1 could significantly enhance pinocytic capacity, reactive oxygen species production, and cytokines secretion. SGP2-1 exerted immunomodulatory effects through interacting with toll-like receptor 2, and activating mitogen-activated protein kinase, phosphatidylinositol-3-kinase/protein kinase B, and nuclear factor-kappa B signaling pathways. These findings indicated that SGP2-1 could be explored as a potential immunomodulatory agent for application in functional foods.

Exopolysaccharide Produced by Probiotic Bacillus albus DM-15 Isolated From Ayurvedic Fermented Dasamoolarishta: Characterization, Antioxidant, and Anticancer Activities

An exopolysaccharide (EPS) was purified from the probiotic bacterium Bacillus albus DM-15, isolated from the Indian Ayurvedic traditional medicine Dasamoolarishta. Gas chromatography-mass spectrophotometry and nuclear magnetic resonance (NMR) analyses revealed the heteropolymeric nature of the purified EPS with monosaccharide units of glucose, galactose, xylose, and rhamnose. Size-exclusion chromatography had shown the molecular weight of the purified EPS as around 240 kDa. X-ray powder diffraction analysis confirmed the non-crystalline amorphous nature of the EPS. Furthermore, the purified EPS showed the maximum flocculation activity (72.80%) with kaolin clay and emulsification activity (67.04%) with xylene. In addition, the EPS exhibits significant antioxidant activities on DPPH (58.17 ± 0.054%), ABTS (70.47 ± 0.854%) and nitric oxide (58.92 ± 0.744%) radicals in a concentration-dependent way. Moreover, the EPS showed promising cytotoxic activity (20 ± 0.97 μg mL^–1) against the lung carcinoma cells (A549), and subsequent cellular staining revealed apoptotic necrotic characters in damaged A549 cells. The EPS purified from the probiotic strain B. albus DM-15 can be further studied and exploited as a potential carbohydrate polymer in food, cosmetic, pharmaceutical, and biomedical applications.

Characterization of the physicochemical properties, antioxidant activity, and antiproliferative activity of natural melanin from S. reiliana

This study aimed to characterize the physicochemical properties and stability of L-25 melanin extracted from Sporisorium reilianum (S. reiliana). The results showed that the maximum absorption wavelength of melanin was 215 nm. Reducing agents, heat, light, microwaving, oxidants, and common food additives did not affect the melanin. Additionally, it has a good metal stability except Mn²⁺. The IR spectra revealed the presence of O–H, N–H, C=O, and C=C bonds as well as carboxyl, alcohol hydroxyl, and phenolic hydroxyl groups and a pyran ring. L-25 melanin could be defined as DL-hydroxy phenylalanine (DOPA)-melanin. The antioxidant and antiproliferative were also measured. The melanin has a specific stability and high antioxidant activity, including a strong DPPH free radical scavenging ability, and protected damaged HepG2 cells by reducing reactive oxygen species, malondialdehyde, and lactate dehydrogenase content. In conclusion, S. reilianum represents a novel source of melanin, that could be applied to health food or food additives. Our results show that melanin from S. reilianum is a natural pigment with good stability that has a great prospect of development and application, providing a theoretical basis and methods for its further processing and development as a functional food.

Temperature mediates metabolism switching of Bacillus sp. ZT-1: Analysis of the properties and structure of exopolysaccharides

Microorganism was very sensitive to external temperature change, which also affected its normal metabolism and secretion. Low temperature exopolysaccharides (LT-EPS) and normal temperature exopolysaccharides (NT-EPS) secreted by Bacillus sp. ZT-1 mediated by temperature were studied in this paper. The total carbohydrate in the LT-EPS and NT-EPS were found to be 82.54 ± 2.56 % and 94.23 ± 1.59 % (w/w). The High Performance Liquid Chromatography (HPLC) revealed the mannose and galacturonic acid accounted for 45.52 and 23.49 % in LT-EPS, respectively. In like manner, mannose and galacturonic acid contained 43.99 and 25.24 % in NT-EPS. One-dimensional nuclear magnetic resonance (NMR) revealed the connection mode of sugar chains. NT-EPS exhibited higher viscosity, better emulsification properties and the larger molecular weight than LT-EPS. Scanning electron microscopy (SEM) showed that LT-EPS was sheet-like with sugar chain branches while NT-EPS was showed as network structure. Furthermore, the 2812 differentially expressed genes (DEGs) were analyzed by Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and located 739 biological pathways. Finally, transcriptome analysis revealed differences in gene expression of the pentose phosphate pathway of carbohydrate metabolism might be the main reason for this difference.

A neutral polysaccharide from Ophiocordyceps lanpingensis restrains cisplatin-induced nephrotoxicity

Ophiocordyceps lanpingensis is an edible mushroom distributed over the south-eastern part of the Tibet Plateau, which is also recognized as an effective ethnomedicine to alleviate diseases. This study explored the effects of a kind of Ophiocordyceps lanpingensis neutral polysaccharide (ONP) on RAW264.7 macrophages and cisplatin-induced nephrotoxicity. The results showed that ONP relieved the inflammatory response of RAW264.7 macrophages by increasing the expression level of anti-inflammatory factor IL-10. Furthermore, ONP treatment significantly prolonged the survival of the mice treated by cisplatin through decelerating pathological progress and alleviating damaged functions of the kidneys. Compared with the cisplatin group, ONP reduced the oxidative stress of the renal cells and the expression levels of pro-inflammatory factors. Apoptosis of renal cells was also weakened in the ONP treatment group. These findings indicated that ONP alleviated cisplatin nephrotoxicity mainly by inhibiting oxidative stress, inflammation, and apoptosis in the kidneys, underscoring the potential of ONP supplementation to alleviate the side effects of cisplatin chemotherapy.

Structure characterization, antioxidant and emulsifying capacities of exopolysaccharide derived from Pantoea alhagi NX-11

Pantoea alhagi exopolysaccharides (PAPS) have been shown to enhance crop resistance to abiotic stress. However, physicochemical properties and structure of PAPS have not yet been analyzed. In this study, two PAPSs, named PAPS1 and PAPS2, were isolated and purified from the P. alhagi NX-11. The results showed PAPS1 and PAPS2 were composed of glucose, galactose, glucuronic acid, glucosamine and mannose with average molecular weight of 1.326 × 10⁶ Da and 1.959 × 10⁶ Da, respectively. Moreover, the structure of PAPS1 and PAPS2 was investigated by FT-IR and NMR analysis. PAPS1 was identified to have the backbone structure of →4)-β-D-GlcpA-(1→2)-α-D-Galp-(1→3)-β-D-Galp-(1→3)-β-D-GlcpN- (1→3)-α-D-Galp-(1→3)-β-D-Galp-(1→. PAPS2 had the backbone structure of →4)-β-D-GlcpA-(1→2)-α-D-Galp-(1→3)-β-D-Glcp-(1→3)-β-D-GlcpN-(1→3)-α-D-Galp-(1→3)-α-D-GlcpN-(1→. In addition, PAPS1 and PAPS2 had moderate antioxidant and emulsifying capacities. Overall, the structure analysis of PAPS may point out the direction for the subsequent study of PAPS-mediated microbial and plant interactions, and further exploration of the application of PAPS.

Purification, Structural Characteristics, and Biological Activities of Exopolysaccharide Isolated From Leuconostoc mesenteroides SN-8

In this study, a novel exopolysaccharide (EPS) was extracted from Leuconostoc mesenteroides Shen Nong's (SN)-8 which can be obtained from Dajiang. After the purification step, EPS-8-2 was obtained with molecular weights of 1.46 × 105 Da. The structural characterization of EPS indicated that the EPS belonged to the class polysaccharide, mainly composed of glucan and also contained certain mannose residues that were found to be connected by α-1,6 glycosidic bonds. Moreover, the results demonstrated that EPS displayed a significant capacity to scavenge free radical to some extent, and this anti-oxidant potential was found to be concentration dependent. The results further revealed that EPS displayed a significant inhibitory potential on the growth of HepG2 cells by promoting apoptosis and induced cell cycle arrest in G1 and G2 phases. Overall, these results suggested that EPS can be explored as a possible anti-cancer agent.

Efficient biosynthesis of exopolysaccharide from Jerusalem artichoke using a novel strain of Bacillus velezensis LT-2

This study focused on the non-grain biorefining of Jerusalem artichoke (JA) for exopolysaccharide (EPS) efficient production by using Bacillus velezensis LT-2. Results showed that LT-2 could directly utilize JA tuber power (JATP) for EPS production, and its EPS yield reached 11.47 ± 0.33 g/L in the simultaneous saccharification and fermentation (SSF) mode. Furthermore, the SSF mode shortened the fermentation period by 26.67% and reduced the fermentation cost by 79.41% due to the improved substrate utilization and the avoidance of inhibition effects of a high fructose concentration. Transcriptome sequencing results showed that inulin could accelerate nucleotide-sugars biosynthesis, induce EPS synthetic gene cluster transcription, and strengthen the electron transport respiratory chain and the transporter systems, thereby ensuring EPS efficient synthesis. This work exhibited a productive non-grain and environmentally friendly fermentation strategy for EPS biosynthesis, which promoted the JA industry development and created new prospects for high-value industrial products biosynthesis by using JATP.