Production, characterization and In vitro antioxidant activities of exopolysaccharide from Weissella cibaria GA44

Slowly hydrolyzable property of microbial dextrans at the small intestinal α-glucosidase levels leads to the modulated glycemic responses in the mouse model

Dextran-type α-glucans have been known as non-digestible ingredients that can be considered prebiotics to promote colon health. However, recent studies have revealed that various α-linked glucosyl units are hydrolyzed to glucose by small intestinal α-glucosidases. This study analyzed the structural characteristics of exopolysaccharides (EPSs) from Weissella species, and the hydrolysis properties at both in vitro/in vivo levels were investigated. Compared with a previous in vitro digestion model using fungal α-hydrolytic enzymes, dextrans, which mainly consist of α-1,6 linkages with small amounts of α-1,3 linked glucose units, were slowly hydrolyzed to glucose by mammalian mucosal α-glucosidases, resulting in attenuation of the initial glycemic response following administration of EPS samples to mice via oral gavage. The results of this study demonstrate the concept of dextran-type α-glucans as glycemic carbohydrates rather than dietary fibers or prebiotics. Slowly digestible dextrans can be applied as a functional ingredient to regulate postprandial glucose delivery throughout the gastrointestinal tract.

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

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

Genomic and functional evaluation of exopolysaccharide produced by Liquorilactobacillus mali t6-52: technological implications

BACKGROUND

This study explores the biosynthesis, characteristics, and functional properties of exopolysaccharide produced by the strain Liquorilactobacillus mali T6-52. The strain demonstrated significant EPS production with a non-ropy phenotype.

RESULTS

The genomic analysis unveiled genes associated with EPS biosynthesis, shedding light on the mechanism behind EPS production. These genes suggest a robust EPS production mechanism, providing insights into the strain's adaptability and ecological niche. Chemical composition analysis identified the EPS as a homopolysaccharide primarily composed of glucose, confirming its dextran nature. Furthermore, it demonstrated notable functional properties, including antioxidant activity, fat absorption capacity, and emulsifying activity. Moreover, the EPS displayed promising cryoprotective activities, showing notable performance comparable to standard cryoprotective agents. The EPS concentration also demonstrated significant freeze-drying protective effects, presenting it as a potential alternative cryoprotectant for bacterial storage.

CONCLUSIONS

The functional properties of L. mali T6-52 EPS reveal promising opportunities across various industrial domains. The strain's safety profile, antioxidant prowess, and exceptional cryoprotective and freeze-drying characteristics position it as an asset in food processing and pharmaceuticals.

Fermentative optimization and characterization of exopolysaccharides from Enterococcus faecium F58 isolated from traditional fresh goat cheese

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.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01424-9.

Exploration of Exopolysaccharide from Leuconostoc mesenteroides HDE-8: Unveiling Structure, Bioactivity, and Food Industry Applications

A strain of Leuconostoc mesenteroides HDE-8 was isolated from homemade longan fermentation broth. The exopolysaccharide (EPS) yield of the strain was 25.1 g/L. The EPS was isolated and purified, and the structure was characterized using various techniques, including X-ray diffraction (XRD), nuclear magnetic resonance (NMR) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, high-performance size exclusion chromatography (HPSEC), and scanning electron microscopy (SEM). The monosaccharide composition of the EPS was glucose, with a molecular weight (Mw) of 1.7 × 106 Da. NMR spectroscopy revealed that the composition of the HDE-8 EPS consisted of D-glucose pyranose linked by α-(1→4) and α-(1→6) bonds. The SEM analysis of the EPS showed an irregular sheet-like structure. Physicochemical analysis demonstrated that EPSs exhibit excellent thermal stability and high viscosity, making them suitable for fermentation in heat-processed and acidic foods. Additionally, milk coagulation tests showed that the presence of EPSs promotes milk coagulation when supplemented with sucrose. It suggests that EPSs have wide-ranging potential applications as food additives, improving the texture and taste of dairy products. This study provides practical guidance for the commercial use of HDE-8 EPSs in the food and related industries.

Antimony precipitation and removal by antimony hyper resistant strain Achromobacter sp. 25-M

Microbes have been confirmed to play key role in biogeochemistry of antimony. However, the impact of indigenous bacteria (from active mines) on the behavior of dissolved antimony remained poorly understood. In current study, the hyper antimony-resistant strain, Achromobacter sp. 25-M, isolated from the world largest antimony deposit, Xikuangshan antimony deposit, was evaluated for its role in dissolved Sb(V) and Sb(III) precipitation and removal. Despite of the high resistance to Sb(III) (up to 50 mM), the facultative alkaliphile, 25-M was not capable of Sb(III) oxidation. Meanwhile 25-M can produce high amount of exopolymeric substance (EPS) with the presence of Sb, which prompted us to investigate the potential role of EPS in the precipitation and removal of Sb. To this end, 2 mM of Sb(III) and Sb(V) were added into the experimental systems with and without 25-M to discern the interaction mechanism between microbe and antimony. After 96 hrs' incubation, 88% [1.73 mM (210 mg/L)] of dissolved Sb(V) and 80% [1.57 mM (190 mg/L)] of dissolved Sb(III) were removed. X-ray diffraction and energy dispersive spectroscopy analysis confirmed the formation of valentinite (Sb2O3) in Sb(III) amended system and a solitary Sb(V) mineral mopungite [NaSb(OH)6] in Sb(V) amended group with microbes. Conversely, no precipitate was detected in abiotic systems. Morphologically valentinite was bowtie and mopungite was pseudo-cubic as indicated by scanning electronic microscopy. EPS was subjected to fourier transform infrared (FT-IR) analysis. FT-IR analysis suggested that -OH and -COO groups were responsible for the complexation and ligand exchange with Sb(III) and Sb(V), respectively. Additionally, the C-H group and N-H group could be involved in π-π interaction and chelation with Sb species. All these interactions between Sb and functional groups in EPS may subsequently favore the formation of valentinite and mopungite. Collectively, current results suggested that EPS play fundamental role in bioprecipitation of Sb, which offered a new strategy in Sb bioremediation.

Enhancing the Antioxidant Potential of Weissella confusa PP29 Probiotic Media through Incorporation of Hibiscus sabdariffa L. Anthocyanin Extract

Lactic acid bacteria (LAB) produce important metabolites during fermentation processes, such as exopolysaccharides (EPS), which represent powerful natural antioxidants. On the other hand, H. sabdariffa L. anthocyanin extracts protect LAB and support their development. This study uncovers for the first time, the antioxidant profile of Weissella confusa PP29 probiotic media and focuses on elevating its impressive antioxidant attributes by synergistically integrating H. sabdariffa L. anthocyanin extract. The multifaceted potential of this innovative approach is explored and the results are remarkable, allowing us to understand the protective capacity of the fermented product on the intestinal mucosa. The total phenolic content was much lower at the end of the fermentation process compared to the initial amount, confirming their LAB processing. The DPPH radical scavenging and FRAP of the fermented products were higher compared to ascorbic acid and antioxidant extracts, while superoxide anion radical scavenging and lipid peroxidation inhibitory activity were comparable to that of ascorbic acid. The antioxidant properties of the fermented products were correlated with the initial inoculum and anthocyanin concentrations. All these properties were preserved for 6 months, demonstrating the promising efficacy of this enriched medium, underlining its potential as a complex functional food with enhanced health benefits.

The Weissella and Periweissella genera: up-to-date taxonomy, ecology, safety, biotechnological, and probiotic potential

Bacteria belonging to the genera Weissella and Periweissella are lactic acid bacteria, which emerged in the last decades for their probiotic and biotechnological potential. In 2015, an article reviewing the scientific literature till that date on the taxonomy, ecology, and biotechnological potential of the Weissella genus was published. Since then, the number of studies on this genus has increased enormously, several novel species have been discovered, the taxonomy of the genus underwent changes and new insights into the safety, and biotechnological and probiotic potential of weissellas and periweissellas could be gained. Here, we provide an updated overview (from 2015 until today) of the taxonomy, ecology, safety, biotechnological, and probiotic potential of these lactic acid bacteria.

Improved production of lactiplantibacillus plantarum RO30 exopolysaccharide (REPS) by optimization of process parameters through statistical experimental designs

BACKGROUND

In investigating of (exopolysaccharide) EPS from unconventional sources, lactic acid bacteria have a vital role due to their generally recognized as safe (GRAS) status. EPSs have diverse applications such as drug delivery, antimicrobial activity, surgical implants, and many more in many sectors. Despite being important, the main hindrance to the commercial application of these significant biopolymers is low productivity. Therefore, this study primarily focuses on optimizing physio-chemical conditions to maximize the previously produced EPS from probiotic Lactiplantibacillus plantarum RO30 (L. plantarum RO30) using one factor at a time (OFAT) and method Response Surface Methodology (RSM).

RESULTS

The EPS obtained from L. plantarum RO30 named REPS. The medium formulation for REPS production using the OFAT method revealed that sucrose (20 g/L, beef extract (25 g/L), and ammonium sulfate at 4 g/L concentration were the optimum carbon, organic and inorganic nitrogen sources, and REPS yield was increased up to 9.11 ± 0.51 g/L. RSM experiments revealed that, a greatly significant quadratic polynomial attained from the Central Composite Design (CCD) model was fruitful for specifying the most favorable cultural conditions that have significant consequences on REPS yield. The maximal amount of REPS (10.32 g/L) was formed by: sucrose (40 g/L), beef extract (25 g/L), pH (5.5), incubation temperature (30 °C), and incubation period (72 h). A high closeness was obtained between the predicted and experimental values and it displayed the efficiency of the RSM.

CONCLUSION

This study was conducted to reinforce REPS production in the probiotic LAB L. plantarum RO30 by utilizing various experimental parameters. The maximum REPS yield of 10.32 g/L was attained under the circumstances optimized in the study.

Weissella confusa N17 Derived from Loach (Misgurnus anguillicaudatus) Exhibits Promising for Further Applications in Loach Aquaculture

The application of probiotics, in aquaculture, is becoming increasingly widespread and have had positive application effects. However, reports of loach-derived probiotics are quite limited. In this study, two representative strains of lactic acid bacteria with excellent traits, namely, Weissella confusa N17 and Lactobacillus saniviri N19, were screened from the intestine of healthy loaches. W. confusa N17 and L. saniviri N19 could inhibit different common various pathogenic bacteria, especially Aeromonas spp., and were sensitive to the most common antibiotics. The survival rate of the two strains exceeded 50% after 4 h of incubation in 10% loach bile. Moreover, the two strains showed significant tolerance to trypsin. Their autoaggregation capacity and hydrophobicity were greater than 30%. In addition, the aggregation ability of both strains was higher than 30% for both A. veronii TH0426 and A. hydrophila TPS. The two strains had a high biofilm-forming ability and strong adhesion to epithelioma papulosum cyprini (EPC) cells. Scanning electron microscopy results showed that the culture supernatants of the two strains had a significantly destructive effect on A. veronii TH0426 and A. hydrophila TPS. Overall, the traits of W. confusa N17 were better than those of L. saniviri N19. Genome sequencing and analysis demonstrated a lack of virulence factor-related or drug resistance-related genes in genome N17. The diet supplemented with the W. confusa N17 strain significantly improved the resistance of loaches to A. veronii infection, and the protection rate reached 57.1%. Therefore, W. confusa N17 exhibits promising for further applications in loach aquaculture.

Dextrans of Weissella cibaria DSM14295: Microbial production, structure and functionality

Lactic acid bacteria of the genus Weissella contribute to spontaneous fermentation in, e.g., sourdough or sauerkraut, but are not registered as starter cultures because of their pending safety assessment. Some strains are able to produce high amounts of exopolysaccharides. This study aims to demonstrate the techno-functionality of five dextrans from W. cibaria DSM14295, produced under varying cultivation conditions, with respect to structural and macromolecular properties. A maximum of 23.1 g/L dextran was achieved by applying the "cold shift" temperature regime. The dextrans differed in molecular mass (9-22∙108 Da, determined by HPSEC-RI/MALLS), intrinsic viscosity (52-73 mL/g), degree of branching (3.8-5.7 % at position O3, determined by methylation analysis) and their side chain length and architecture, determined by HPAEC-PAD after enzymatic hydrolysis. Stiffness of acid gels from milk spiked with these dextrans increased linearly with dextran concentration. Principal component analysis showed that dextrans produced in a semi-defined medium are primarily described by moisture sorption and branching properties, whereas dextrans produced in whey permeate were similar because of their functional and macromolecular properties. Overall, dextrans from W. cibaria DSM14295 have a high potential because of the high production yield and their functionality which can be tailored by the conditions during fermentation.

Structural characteristics and biological activity of lactic acid bacteria exopolysaccharides separated by ethanol/(NH4)2SO4 ATPS

Exopolysaccharides (EPS) from lactic acid bacteria (LAB) as edible and safe bioproducts with health benefits have become an interesting topic. In this study, aqueous two-phase system (ATPS) was established using ethanol and (NH₄)₂SO₄ as phase-forming substances to separate and purify LAB EPS from Lactobacillus plantarum 1.0665. The operating conditions were optimized by a single factor and response surface method (RSM). The results indicated that an effectively selective separation of LAB EPS was achieved by the ATPS consisted of 28 % (w/w) ethanol and 18 % (w/w) (NH₄)₂SO₄ at pH 4.0. Under optimized conditions, the partition coefficient (K) and recovery rate (Y) were well matched with the predicted value of 3.83 ± 0.019 and 74.66 ± 1.05 %. The physicochemical properties of purified LAB EPS were characterized by various technologies. According to the results, LAB EPS was a complex polysaccharide with a triple helix structure mainly composed of mannose, glucose and galactose in the molar ratio of 1.00: 0.32: 0.14, and it proved that the ethanol/(NH₄)₂SO₄ system had good selectivity for LAB EPS. In addition, LAB EPS displayed excellent antioxidant activity, antihypertension activity, anti-gout capacity and hypoglycemic activity in vitro analysis. The results suggested that LAB EPS could be a dietary supplement applied in functional foods.

Impact of exopolysaccharides-producing lactic acid bacteria on the chemical, rheological properties of buckwheat sourdough and the quality of buckwheat bread

Exopolysaccharides (EPS) produced in situ by lactic acid bacteria (LAB) during sourdough fermentation have the potential to replace hydrocolloids in gluten-free sourdoughs. This study investigated effects of an EPS-producing Weissella cibaria NC516.11 fermentation on chemical, rheological properties of sourdough and the quality of buckwheat bread. Results indicate that the buckwheat sourdough fermentation by W. cibaria NC516.11 had lower pH (4.47) and higher total titrable acidity (8.36 mL) compared with other groups, and the polysaccharide content reached 3.10 ± 0.16 g/kg. W. cibaria NC516.11 can significantly improve the rheological properties and viscoelastic properties of sourdough. Compared with control group, the baking loss of NC516.11 group bread decreased by 19.94%, specific volume increased by 26.03%, and showed good appearance and cross-sectional morphology. Scanning electron micrograph revealed an intact and less porous cell structure. Meanwhile, W. cibaria NC516.11 significantly improved the texture of the bread and reduced the hardness and moisture loss during storage.

Optimization, Probiotic Characteristics, and Rheological Properties of Exopolysaccharides from Lactiplantibacillus plantarum MC5

This study optimized the exopolysaccharides (EPS) production for Lactiplantibacillus plantarum MC5 (Lp. plantarum MC5) and evaluated the resistance to human simulated digestive juices, antioxidant activity in vitro, and rheological properties of EPS-MC5. The results showed that maximum EPS production of 345.98 mg/L (about 1.5-old greater than the initial production) was obtained at optimal conditions of inoculum size (4.0%), incubation time (30 h), incubation temperature (34.0 °C), and initial pH value (6.40). Furthermore, the resisting-digestion capacity of EPS-MC5 after 180 min in α-amylase, simulated gastric juice (pH 2.0, 3.0, 4.0), and simulated intestinal juice (pH 6.8) was 98.59%, 98.62%, 98.78%, 98.86%, and 98.74%, respectively. In addition, the radical scavenging rates of DPPH•, ABTS•, •OH, and ferric-iron reducing power (OD700) of EPS-MC5 were 73.33%, 87.74%, 46.07%, and 1.20, respectively. Furthermore, rheological results showed that the EPS-MC5 had a higher apparent viscosity (3.01 Pa) and shear stress (41.78 Pa), and the viscoelastic modulus (84.02 and 161.02 Pa at the shear frequency of 100 Hz). These results provide a new insight into the application of EPS in human health and functional foods, which could also improve theoretical guidance for the industrial application of EPS.

Diet Diversification and Priming with Kunu: An Indigenous Probiotic Cereal-Based Non-Alcoholic Beverage in Nigeria

Kunu is a fermented non-alcoholic beverage consumed all over Nigeria. The drink is served as an alternative to alcohol due to its perceived extreme nourishing and therapeutic properties. Varieties of this beverage are determined mostly by the type of grain, the supplements, sensory additives used, and the process employed during its production. Dietary quality is paramount in nutritional well-being and a key factor in human overall health development. The nutritional quality of grains utilised for Kunu production makes the drink more appealing to a large growing population when compared to some other drinks. Some use Kunu drink as an infant weaning drink, thus serving as a priming beverage for infants due to its rich probiotic and nutritional properties. However, this beverage’s short shelf-life has limited its production scale. This review therefore elaborates succinctly on the diverse therapeutic nutritional properties of the Kunu beverage and the effect of additives and fermentation on the microbial dynamics during Kunu production, as well as the prospect of Kunu in diet diversification and priming for weaning infants.

The Weissella Genus: Clinically Treatable Bacteria with Antimicrobial/Probiotic Effects on Inflammation and Cancer

Weissella is a genus earlier considered a member of the family Leuconostocaceae, which was reclassified into the family Lactobacillaceae in 1993. Recently, there have been studies emphasizing the probiotic and anti-inflammatory potential of various species of Weissella, of which W. confusa and W. cibaria are the most representative. Other species within this genus include: W. paramesenteroides, W. viridescens, W. halotolerans, W. minor, W. kandleri, W. soli, W. ghanensis, W. hellenica, W. thailandensis, W. fabalis, W. cryptocerci, W. koreensis, W. beninensis, W. fabaria, W. oryzae, W. ceti, W. uvarum, W. bombi, W. sagaensis, W. kimchi, W. muntiaci, W. jogaejeotgali, W. coleopterorum, W. hanii, W. salipiscis, and W. diestrammenae. Weissella confusa, W. paramesenteroides, W. koreensis, and W. cibaria are among the few species that have been isolated from human samples, although the identification of these and other species is possible using metagenomics, as we have shown for inflammatory bowel disease (IBD) and healthy controls. We were able to isolate Weissella in gut-associated bacteria (post 24 h food deprivation and laxatives). Other sources of isolation include fermented food, soil, and skin/gut/saliva of insects/animals. With the potential for hospital and industrial applications, there is a concern about possible infections. Herein, we present the current applications of Weissella on its antimicrobial and anti-inflammatory mechanistic effects, the predisposing factors (e.g., vancomycin) for pathogenicity in humans, and the antimicrobials used in patients. To address the medical concerns, we examined 28 case reports focused on W. confusa and found that 78.5% of infections were bacteremia (of which 7 were fatal; 1 for lack of treatment), 8 were associated with underlying malignancies, and 8 with gastrointestinal procedures/diseases of which 2 were Crohn’s disease patients. In cases of a successful resolution, commonly administered antibiotics included: cephalosporin, ampicillin, piperacillin-tazobactam, and daptomycin. Despite reports of Weissella-related infections, the evolving mechanistic findings suggest that Weissella are clinically treatable bacteria with emerging antimicrobial and probiotic benefits ranging from oral health, skin care, obesity, and inflammatory diseases to cancer.

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.

Peptides, Exopolysaccharides, and Short-Chain Fatty Acids from Fermented Milk and Perspectives on Inflammatory Bowel Diseases

Crohn's disease and ulcerative colitis are characterized by chronic inflammatory processes and an imbalanced immune response along the gastrointestinal (GI) tract. Pharmacological treatments have been widely used, although their long-term application has adverse side effects. On the other hand, milks fermented with specific lactic acid bacteria (LAB) have been shown to be useful as alternative or complementary aids. Many metabolites such as peptides, exopolysaccharides, and short-chain fatty acids are produced during milk fermentation. These components have been shown to change the pH of the gastrointestinal lumen, aid intestine mucosal recovery, modulate the microbiota, and reduce the inflammatory response (innate and adaptive immune system), both in vitro and in vivo. Therefore, the objective of the present review is to describe how these bioactive compounds from fermented milk by specific LAB can decrease the deleterious symptoms of inflammatory bowel disease.

Exopolysaccharides of Lactic Acid Bacteria: Production, Purification and Health Benefits towards Functional Food

Lactic acid bacteria (LAB) are capable of synthesising metabolites known as exopolysaccharides (EPS) during fermentation. Traditionally, EPS plays an important role in fermented dairy products through their gelling and thickening properties, but they can also be beneficial to human health. This bioactivity has gained attention in applications for functional foods, which leads them to have prebiotic, immunomodulatory, antioxidant, anti-tumour, cholesterol-lowering and anti-obesity activity. Understanding the parameters and conditions is crucial to optimising the EPS yields from LAB for applications in the food industry. This review provides an overview of the functional food market together with the biosynthesis of EPS. Factors influencing the production of EPS as well as methods for isolation, characterisation and quantification are reviewed. Finally, the health benefits associated with EPS are discussed.

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.

Broad-spectrum antimicrobial activity of cinnamoyl esterase-producing Lactobacilli and their application in fermented rice bran

BACKGROUND

Cinnamoyl esterase (CE) can release antioxidant phenolic acids from its non-digestible ester-linked form. Fermentation using CE-producing lactic acid bacteria (LAB) can be useful in the food industry because of its ability to produce bioactive compounds and antibacterial metabolites. The purpose of this study was to confirm the food applicability of LAB with CE-producing ability and broad-spectrum antibacterial activity.

RESULTS

Among the 219 bacterial strains identified in infant feces, five Lactobacillus gasseri and six Limosilactobacillus fermentum with a high CE activity were isolated. The survival rate of all selected LABs was > 95% at pH 2.5 for 3 h and > 70% when treated with 0.3% bile salt for 4 h. Moreover, cell-free supernatants of all strains strongly inhibited five food-borne bacterial pathogens (Listeria monocytogenes, Salmonella enterica, Escherichia coli O157:H7, Bacillus cereus, and Staphylococcus aureus) and three toxin-producing fungal pathogens (Aspergillus niger, Penicillium sp., and Fusarium oxysporum). To improve phenolic acid content and rice bran preservation, Limosilactobacillus fermentum J2 with the strongest CE activity and Lactobacillus gasseri N2 with the strongest antibacterial activity were used in rice bran fermentation, respectively. FRB-J2 (fermented rice bran with Limosilactobacillus fermentum J2) and FRB-N2 (fermented rice bran with Lactobacillus gasseri N2) significantly increased caffeic acid and ferulic acid (P < 0.01). FRB-J2 and FRB-N2 artificially inoculated with F. oxysporum showed no visible fungal growth during the test period (21 days).

CONCLUSION

Fermentation by Limosilactobacillus fermentum J2 and Lactobacillus gasseri N2 can help extend the shelf life of rice bran-based products and produce bioactive compounds. © 2021 Society of Chemical Industry.

Evaluation of the Probiotic Potential of Lactobacillus delbrueckii ssp. indicus WDS-7 Isolated from Chinese Traditional Fermented Buffalo Milk In Vitro

The present study aimed to evaluate the probiotic potential of lactic acid bacteria (LAB) isolated from Chinese traditional fermented buffalo milk. Out of 22 isolates, 11 were putatively identified as LAB preliminarily. A total of six LAB strains displayed strong adhesion to HT-29 cells and all these strains showed preferable tolerance to artificially simulated gastrointestinal juices. WDS-4, WDS-7, and WDS-18 exhibited excellent antioxidant capacities, including DPPH radical, ABTS⁺ radical, and superoxide anion scavenging activities. Compared with the other two LAB strains, WDS-7 had a stronger inhibition effect on four pathogens. Based on the 16S rRNA gene sequencing and phylogenetic analysis, WDS-7 was identified as Lactobacillus delbrueckii ssp. indicus and selected to assess the potential and safety of probiotics further. The results revealed that WDS-7 strain had a strong capacity for acid production and good thermal stability. WDS-7 strain also possessed bile salt hydrolase (BSH) activity. Compared to LGG, WDS-7 was a greater biofilm producer on the plastic surface and exhibited a better EPS production ability (1.94 mg/ml as a glucose equivalent). WDS-7 was proved to be sensitive in the majority of tested antibiotics and absence of hemolytic activity. Moreover, no production of biogenic amines and β-glucuronidase was observed in WDS-7. The findings of this work indicated that L. delbrueckii ssp. indicus WDS-7 fulfilled the probiotic criteria in vitro and could be exploited for further evaluation in vivo.

Oxidative stress alleviating potential of galactan exopolysaccharide from Weissella confusa KR780676 in yeast model system

In the present study, galactan exopolysaccharide (EPS) from Weissella confusa KR780676 was evaluated for its potential to alleviate oxidative stress using in vitro assays and in vivo studies in Saccharomyces cerevisiae (wild type) and its antioxidant (sod1∆, sod2∆, tsa1∆, cta2∆ and ctt1∆), anti-apoptotic (pep4∆ and fis1∆) and anti-aging (sod2∆, tsa1∆ and ctt1∆)) isogenic gene deletion mutants. Galactan exhibited strong DPPH and nitric oxide scavenging activity with an IC₅₀ value of 450 and 138 µg/mL respectively. In the yeast mutant model, oxidative stress generated by H₂O₂ was extensively scavenged by galactan in the medium as confirmed using spot assays followed by fluorescencent DCF-DA staining and microscopic studies. Galactan treatment resulted in reduction in the ROS generated in the yeast mutant cells as demonstrated by decreased fluorescence intensity. Furthermore, galactan exhibited protection against oxidative damage through H₂O₂ -induced apoptosis inhibition in the yeast mutant strains (pep4∆ and fis1∆) leading to increased survival rate by neutralizing the oxidative stress. In the chronological life span assay, WT cells treated with galactan EPS showed 8% increase in viability whereas sod2∆ mutant showed 10–15% increase indicating pronounced anti-aging effects. Galactan from W. confusa KR780676 has immense potential to be used as a natural antioxidant for nutraceutical, pharmaceutical and food technological applications. As per our knowledge, this is the first report on in-depth assessment of in vivo antioxidant properties of a bacterial EPS in a yeast deletion model system.

Exopolysaccharides Produced by Lactic Acid Bacteria: From Biosynthesis to Health-Promoting Properties

The production of exopolysaccharides (EPS) by lactic acid bacteria (LAB) has attracted particular interest in the food industry. EPS can be considered as natural biothickeners as they are produced in situ by LAB and improve the rheological properties of fermented foods. Moreover, much research has been conducted on the beneficial effects of EPS produced by LAB on modulating the gut microbiome and promoting health. The EPS, which varies widely in composition and structure, may have diverse health effects, such as glycemic control, calcium and magnesium absorption, cholesterol-lowering, anticarcinogenic, immunomodulatory, and antioxidant effects. In this article, the latest advances on structure, biosynthesis, and physicochemical properties of LAB-derived EPS are described in detail. This is followed by a summary of up-to-date methods used to detect, characterize and elucidate the structure of EPS produced by LAB. In addition, current strategies on the use of LAB-produced EPS in food products have been discussed, focusing on beneficial applications in dairy products, gluten-free bakery products, and low-fat meat products, as they positively influence the consistency, stability, and quality of the final product. Highlighting is also placed on reports of health-promoting effects, with particular emphasis on prebiotic, immunomodulatory, antioxidant, cholesterol-lowering, anti-biofilm, antimicrobial, anticancer, and drug-delivery activities.

Structural characterization of exopolysaccharides from Weissella cibaria NC516.11 in distiller grains and its improvement in gluten-free dough

In this study, an exopolysaccharide (EPS) was produced by Weissella cibaria NC516.11 isolated from distiller grains of Chinese Baijiu. The structural characterization of EPS determined using fourier transform infrared spectra and nuclear magnetic resonance spectra demonstrated that W. cibaria NC516.11 had α-(1 → 6) (93.46%) d-glucose linkages with a few α-(1 → 3) (6.54%) d-glucose linked branches. The monosaccharide composition of the EPS was glucose, and its molecular weight was 2.82 × 10⁶ Da. Scanning electron microscopy showed that the microstructure of EPS had a three-dimensional structure at low magnification and a particle structure that protruded from the surface at high magnification. The addition of EPS into dough can promote the cross-linking of starch molecules and increase the water-holding capacity. Dynamic rheology indicated that the aqueous solution of EPS is a pseudoplastic fluid, and the higher the concentration of EPS, the greater the viscosity. The addition of EPS to the gluten-free dough showed G' > G", which could increase the viscoelastic properties of the dough and enhance the gluten network.

Investigation on exopolysaccharide production by Lacticaseibacillus rhamnosus P14 isolated from Moroccan raw cow's milk

Twenty-four strains were isolated from 50 samples of raw cow's milk originated from different regions of Morocco. After different screening methods, one strain was selected as the highest exopolysaccharide (EPS)-producing isolate and was identified by 16S rDNA sequencing as Lacticaseibacillus rhamnosus P14. Moreover, the EPS-producing ability, bacterial growth, and pH of the medium were monitored. The optimization of culture conditions indicated that the high yield of EPS was 685.14 mg/L obtained at 42°C, with lactose as a carbon source. The characterization study showed that the purified EPS consisted of one main fraction that contained 97.67% of carbohydrates. Furthermore, the EPS was identified as a homogeneous polysaccharide, mainly composed of glucose. These results demonstrated the high EPS production ability of the selected L. rhamnosus P14, representing a promising candidate to improve the textural and sensory properties of fermented food.

Antioxidant Potential of the Bio-Based Fucose-Rich Polysaccharide FucoPol Supports Its Use in Oxidative Stress-Inducing Systems

Reactive oxygen species (ROS) are dangerous sources of macromolecular damage. While most derive from mitochondrial oxidative phosphorylation, their production can be triggered by exogenous stresses, surpassing the extinction capacity of intrinsic antioxidant defense systems of cells. Here, we report the antioxidant activity of FucoPol, a fucose-rich polyanionic polysaccharide produced by Enterobacter A47, containing ca. 17 wt% of negatively charged residues in its structure. Ferric reducing antioxidant power (FRAP) assays coupled to Hill binding kinetics fitting have shown FucoPol can neutralize ferricyanide and Fe3+-TPTZ species at an EC50 of 896 and 602 µg/mL, respectively, with positive binding cooperativity (2.52 ≤ H ≤ 4.85). This reducing power is greater than most polysaccharides reported. Moreover, an optimal 0.25% w/v FucoPol concentration shown previously to be cryo- and photoprotective was also demonstrated to protect Vero cells against H2O2-induced acute exposure not only by attenuating metabolic viability decay, but also by accentuating post-stress proliferation capacity, whilst preserving cell morphology. These results on antioxidant activity provide evidence for the biopolymer's ability to prevent positive feedback cascades of the radical-producing Fenton reaction. Ultimately, FucoPol provides a biotechnological alternative for implementation in cryopreservation, food supplementation, and photoprotective sunscreen formula design, as all fields benefit from an antioxidant functionality.

Characterization and Antioxidant Activity of Released Exopolysaccharide from Potential Probiotic Leuconostoc mesenteroides LM187

A released exopolysaccharide (rEPS)-producing strain (LM187) with good acid resistance, bile salt resistance, and cholesterol-lowering properties was isolated from Sichuan paocai and identified as Leuconostoc mesenteroides subsp. mesenteroides. The purified rEPS, designated as rEPS414, had a uniform molecular weight of 7.757 × 10⁵ Da. Analysis of the monosaccharide composition revealed that the molecule was mainly composed of glucose. The Fourier transform-infrared spectrum showed that rEPS414 contained both α-type and β-type glycosidic bonds. ¹H and ¹³C nuclear magnetic resonance spectra analysis showed that the purified rEPS contained arabinose, galactose, and rhamnose, but less uronic acid. Scanning electron microscopy demonstrated that the exopolysaccharide displayed a large number of scattered, fluffy, porous cellular network flake structures. In addition, rEPS414 exhibited strong in vitro antioxidant activity. These results showed that strain LM187 and its rEPS are promising probiotics with broad prospects in industry.

Antioxidants: Classification, Natural Sources, Activity/Capacity Measurements, and Usefulness for the Synthesis of Nanoparticles

Natural extracts are the source of many antioxidant substances. They have proven useful not only as supplements preventing diseases caused by oxidative stress and food additives preventing oxidation but also as system components for the production of metallic nanoparticles by the so-called green synthesis. This is important given the drastically increased demand for nanomaterials in biomedical fields. The source of ecological technology for producing nanoparticles can be plants or microorganisms (yeast, algae, cyanobacteria, fungi, and bacteria). This review presents recently published research on the green synthesis of nanoparticles. The conditions of biosynthesis and possible mechanisms of nanoparticle formation with the participation of bacteria are presented. The potential of natural extracts for biogenic synthesis depends on the content of reducing substances. The assessment of the antioxidant activity of extracts as multicomponent mixtures is still a challenge for analytical chemistry. There is still no universal test for measuring total antioxidant capacity (TAC). There are many in vitro chemical tests that quantify the antioxidant scavenging activity of free radicals and their ability to chelate metals and that reduce free radical damage. This paper presents the classification of antioxidants and non-enzymatic methods of testing antioxidant capacity in vitro, with particular emphasis on methods based on nanoparticles. Examples of recent studies on the antioxidant activity of natural extracts obtained from different species such as plants, fungi, bacteria, algae, lichens, actinomycetes were collected, giving evaluation methods, reference antioxidants, and details on the preparation of extracts.

Anticancer potential of an exopolysaccharide from Lactobacillus helveticus MB2-1 on human colon cancer HT-29 cells via apoptosis induction

This study aimed at investigating the anticancer activity of an exopolysaccharide (EPS) isolated from Lactobacillus helveticus MB2-1. The crude EPS from L. helveticus MB2-1 (LHEPS) was fractionated into three fractions, namely LHEPS-1, LHEPS-2 and LHEPS-3. LHEPS-1 exhibited the most effective anti-proliferative activity, which was associated with a stronger inhibition rate and increased lactate dehydrogenase leakage of human colon cancer HT-29 cells. Flow cytometry analysis and colorimetric assay revealed that LHEPS-1 induced cell cycle arrest by preventing G1 to S transition and increased the apoptosis rate. Furthermore, LHEPS-1 enhanced the production of intracellular reactive oxygen species (ROS) and the activity of caspases-8/9/3, increased the levels of pro-apoptotic Bax and mitochondrial cytochrome c, while decreased the anti-apoptotic Bcl-2 level, indicating that LHEPS-1 might induce the apoptosis of HT-29 cells through a ROS-dependent pathway and a mitochondria-dependent pathway. These findings suggest that LHEPS-1 may be developed as an effective food and/or drug for the prevention and therapeutics of cancer, especially human colon cancer.

Microbial exopolysaccharide production of Streptococcus thermophilus and its antiquorum sensing activity

Interest in the production of exopolysaccharides by microorganisms has increased in the recent years. Using low-cost product is the main step of microbial production to reduce cost and compete with chemical production. In this work, EPS production of Streptococcus thermophilus isolates from yogurt (S2), kefir (S3), and S. thermophilus ATCC 19258 (S1) isolate which was used as control strains were investigated by using different fruit pulps. S. thermophilus isolates were identified by morphological and 16S sequence analysis. The amount of EPS obtained was measured spectrophotometrically using glucose as standard with phenol sulfuric acid method. All three isolates produced higher amounts of EPS on M17 medium than Nutrient medium. When the fruit pulp was added to the medium, EPS production increased in all three isolates. When different nitrogen sources were added together with fruit pulp juice, EPS production increased. The highest amount of EPS produced by ATCC 19258 strain (21.570 mg/L) and S3 isolate (29.131 mg/L) is the medium where mixed fruit pulp juice and nitrogen source is tryptophan. It has been shown that EPS production is increased by adding fruit pulps to the prepared media. It is thought that apricot pulp can be a good alternative in EPS production especially in the evaluation of wastes. Also, antiquorum sensing activity of the highest amount EPS was determined by using Chromobacterium violaceum CV026 strain and found effective on violacein pigment inhibition and C6-AHL production of biosensor strain.

Production, Characterization, and Antioxidant Activities of an Exopolysaccharide Extracted from Spent Media Wastewater after Leuconostoc mesenteroides WiKim32 Fermentation

Bacterial exopolysaccharides (EPSs) are important alternatives to plant polysaccharides in fermented products and exhibit antioxidant activity, which is particularly desirable for functional foods. This study evaluated the use of spent media wastewater (SMW) derived from kimchi fermentation for the production of an EPS and analyzed the characterization and antioxidant activity of the resulting EPS. The EPS concentration and conversion yields of sequential purification were 7.7-9.0 g/L and 38.6-45.1%, respectively. Fourier transform infrared spectra and NMR spectra indicated that the EPS was a linear glucan with α-(1 → 6) linkages. The EPS also exhibited thermal tolerance to high temperatures. In vitro antioxidant activity analyses indicated the scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, thiobarbituric acid reactance (TBAR), and ferric ion reducing antioxidant power (FRAP) values of 71.6-79.1, 28.2-33.0%, and 0.04-0.05 mM FeCl3, respectively. These results reveal that the EPS extracted from SMW has potential as a thermally tolerant, nontoxic, and natural antioxidant for industrial applications.

Daqu microbiota exhibits species-specific and periodic succession features in Chinese baijiu fermentation process

Daqu, a brick-shaped product spontaneously fermented under an open environment, has been regarded as the starter of fermentation, raw enzyme preparation and raw materials for baijiu production. However, its contribution in baijiu fermentation has not been fully elaborated yet. Here, the effects of daqu microbiota on baijiu fermentation were investigated under both field-scale and lab-scale conditions. In field-scale baijiu fermentation, the dominant daqu microbes (average relative abundance>10.0%), including unclassified_Leuconostocaceae, Thermoascus, and Thermomyces, tended to dominate the early stage (0-7 d). However, the rare daqu microbes (average relative abundance <0.1%, e.g., Kazachstania) tended to dominate the middle and late stages (11-40 d). In addition, some genera showed differences in species diversity between daqu and fermented grains. The average relative abundance of Lactobacillus was over 75% during baijiu fermentation, and most of them were affiliated with Lactobacillus acetotolerans, while Lactobacillus crustorum dominated the Lactobacillus OTUs in daqu. The similar patterns were also observed during lab-scale baijiu fermentation. The results of function prediction showed the enriched metabolic pathways were associated with glycolysis and long-chain fatty acid esters in baijiu fermentation. These results improved the understanding of daqu microbiota function during baijiu fermentation and provided a basic theory to support the regulation of baijiu production.

Weissella: An Emerging Bacterium with Promising Health Benefits

Weissella strains have been the subject of much research over the last 5 years because of the genus' technological and probiotic potential. Certain strains have attracted the attention of the pharmaceutical, medical, and food industries because of their ability to produce antimicrobial exopolysaccharides (EPSs). Moreover, Weissella strains are able to keep foodborne pathogens in check because of the bacteriocins, hydrogen peroxide, and organic acids they can produce; all listed have recognized pathogen inhibitory activities. The Weissella genus has also shown potential for treating atopic dermatitis and certain cancers. W. cibaria, W. confusa, and W. paramesenteroides are particularly of note because of their probiotic potential (fermentation of prebiotic fibers) and their ability to survive in the gastrointestinal tract. It is important to note that most of the Weissella strains with these health-promoting properties have been shown to be save safe, due to the absence or the low occurrence of virulence or antibiotic-resistant genes. A large number of scientific studies continue to report on and to support the use of Weissella strains in the food and pharmaceutical industries. This review provides an overview of these studies and draws conclusions for future uses of this rich and previously unexplored genus.

Optimization of ultrasound-assisted extraction of polysaccharides from perilla seed meal by response surface methodology: Characterization and in vitro antioxidant activities

In this study, response surface methodology was employed to optimize the ultrasound-assisted extraction (UAE) process of perilla seed meal polysaccharides (PSMP). The optimal conditions for UAE of PSMP were: liquid-solid ratio of 26.00 mL/g, ultrasonic temperature of 43.00 °C, ultrasonic time of 52.00 min, and ultrasonic power of 229.00 W, the optimal conditions lead to an yield of 6.137 ± 0.062%. The structural characteristics of molecular weight, compositional monosaccharides, and glycosidic linkages were determined by size exclusion chromatography with multiangle light scattering, gas chromatography-mass spectrometry, Fourier-transfer infrared spectroscopy, and nuclear magnetic resonance detections. Scanning electron microscopy analysis showed that many holes were formed on the surface of PSM after UAE. The antioxidant activities of PSMP were investigated using various assays in vitro. The results suggested that PSMP is potential natural resource of antioxidants for medicine and functional foods. PRACTICAL APPLICATION: The selection of raw material perilla seed meal is conducive to the comprehensive utilization of edible resources. With consumer demands for newly developed foods with natural, wholesome ingredients are increasing nowadays. This study provides effective reference for in-depth research on other medicine-food dual-use resources. Ultrasound-assisted extraction (UAE) is a promising alternative method for hot water reflux extraction (HWRE) of polysaccharides for advantages of high efficiency and energy saving. In this work, the UAE process optimized by response surface methodology is more suitable for industrial application that can effectively decrease total cost of production by reducing the extraction temperature, shortening extraction time, and increasing raw material utilization.

Enzymatically synthesized exopolysaccharide of a probiotic strain Leuconostoc mesenteroides NTM048 shows adjuvant activity to promote IgA antibody responses

Leuconostoc mesenteroides strain NTM048 produces an exopolysaccharide (EPS; glucose polymers 94% and fructose polymers 6%) with adjuvanticity for mucosal vaccination. Strain NTM048 includes three putative EPS-synthesizing genes, gtf1 and gtf2 for synthesizing glucose polymers, and lvnS for synthesizing fructose polymer. To elucidate the key polymer structure for adjuvanticity, two genes, gtf1 and gtf2, which were annotated as glycoside hydrolase family 70 enzyme genes, were expressed in Escherichia coli. Glycosyl-linkage composition analysis and NMR analysis showed that the recombinant enzyme Gtf1 produced a soluble form of α-1,6-glucan, whereas the recombinant enzyme Gtf2 produced glucans with approximately equal percentages of α-1,6- and α-1,3-glucose residues both in the supernatant (S-glucan) and as a precipitate (P-glucan). Comparison of polysaccharides synthesized by Gtf1, Gtf2, and LvnS revealed that Gtf2-S-glucan, which was produced in the supernatant by Gtf2 and formed particles of 7.8 µm, possessed 1.8-fold higher ability to stimulate IgA production from murine Peyer's patch cells than native NTM048 EPS. Evaluation of adjuvanticity by intranasal administration of mice with an antigen (ovalbumin) and Gtf2-S-glucan or NTM048 EPS showed that Gtf2-S-glucan induced the production of higher antigen-specific antibodies in the airway mucosa and plasma, suggesting a pivotal role of Gtf2-S-glucan in the adjuvanticity of NTM048 EPS.

Lactic Acid Bacterial Production of Exopolysaccharides from Fruit and Vegetables and Associated Benefits

Microbial polysaccharides have interesting and attractive characteristics for the food industry, especially when produced by food grade bacteria. Polysaccharides produced by lactic acid bacteria (LAB) during fermentation are extracellular macromolecules of either homo or hetero polysaccharidic nature, and can be classified according to their chemical composition and structure. The most prominent exopolysaccharide (EPS) producing lactic acid bacteria are Lactobacillus, Leuconostoc, Weissella, Lactococcus, Streptococcus, Pediococcus and Bifidobacterium sp. The EPS biosynthesis and regulation pathways are under the dependence of numerous factors as producing-species or strain, nutrient availability, and environmental conditions, resulting in varied carbohydrate compositions and beneficial properties. The interest is growing for fruits and vegetables fermented products, as new functional foods, and the present review is focused on exploring the EPS that could derive from lactic fermented fruit and vegetables. The chemical composition, biosynthetic pathways of EPS and their regulation mode is reported. The consequences of EPS on food quality, especially texture, are explored in relation to producing species. Attention is given to the scientific investigations on health benefits attributed to EPS such as prebiotic, antioxidant, anti-inflammatory and cholesterol lowering activities.

Weissella cibaria EIR/P2-derived exopolysaccharide: A novel alternative to conventional biomaterials targeting periodontal regeneration

Healing and regeneration of periodontium are considered as a complex physiological process. Therefore, treatments need to be addressed with highly effective components modulating the multiple pathways. In this study, exopolysaccharide (EPS) produced by Weissella cibaria EIR/P2, was partially purified from the culture supernatant and subjected to characterization within the aim of evaluating its potential for periodontal regeneration. High-Performance Liquid Chromatography analysis revealed a single-peak corresponding to the glucose which identified the EPS as dextran. Fourier transform-infrared spectra were also displayed characteristic peaks for polysaccharides. According to the results of gel permeation/size exclusion-chromatography, the molecular mass was determined to be 8 × 10⁶ Da. To clarify its anti-bacterial activity on Streptococcus mutans, effects on viability and biofilm formation was evaluated. At 50 mg/mL, dextran exhibited a bactericidal effect with 70% inhibition on biofilm formation. Besides, dose-dependent antioxidant effects were also detected. The efficacy of dextran in enhancing the viability of human periodontal ligament fibroblast cells (hPDLFCs) was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) assay, and an increase was observed in the viability of hPDLFCs. In conclusion, dextran derived from W. cibaria can be potentially used as a multi-functional bioactive polymer in the design of new therapeutic strategies to promote healing and regeneration of periodontium.

Overview of exopolysaccharides produced by Weissella genus - A review

Exopolysaccharides (EPS) from lactic acid bacteria (LAB) are much diversed in structure, composition and applications which also adding a great commercial potential due to its generally recognized as safe (GRAS) status. LAB genus such as Lactobacillus, Leuconostoc, Streptococcus, Weissella, Lactococcus are known to produce EPS. Among this genus, Weissella is enormously reported for diversity and high production of EPS with wide range of industrial applications and bio-functional properties. This review summarize in detail about the Weissella EPS from genus to functional application. Physico-chemical characterization from production, purification step to structural elucidation of Weissella EPS is comprehensively discussed along with their properties. Weissella genus has revealed various EPS with significant functional potentials, making massive application in food and pharma industries as viscosifiers, biothickener, emulsifiers and stabilizers. In addition to this, biological properties of these EPS revealed multiple health promoting properties which can be explored for further applications in food and pharmaceutical sectors.

Influences of drying methods on the structural, physicochemical and antioxidant properties of exopolysaccharide from Lactobacillus helveticus MB2-1

In this study, in order to evaluate influences of different drying methods on the structural characteristics, physicochemical properties and antioxidant activities of exopolysaccharides (EPS) from Lactobacillus helveticus MB2-1, three drying methods, including spray-drying (SD), freeze-drying (FD) and spray freeze-drying (SFD), were applied to dry EPS. Results showed that different drying procedures had no significant influence on the primary structure and constituent monosaccharides of EPSs. However, the surface morphology of the three dried EPSs varied greatly in size and shape due to different drying processes. Among three dried EPSs, the particle size distribution of spray freeze-dried EPS (SF-EPS) was relatively narrower and uniform. Additionally, SF-EPS behaved better apparent viscosity and emulsifying property than spray-dried EPS (S-EPS) and freeze-dried EPS (F-EPS). SF-EPS exhibited stronger antioxidant activities when compared with S-EPS and F-EPS, according to the results of scavenging activities on different radicals and chelating activity on ferrous ion. Overall, SFD was the appropriate method for industrial production of EPS from Lactobacillus helveticus MB2-1 with better physicochemical properties and antioxidant activities.