Exopolysaccharides of Lactobacillus rhamnosus GG ameliorate Salmonella typhimurium-induced intestinal inflammation via the TLR4/NF-κB/MAPK pathway

Background Salmonella typhimurium(S.T),as an important foodborne bacterial pathogen,can cause diarrhea and gastroenteritis in humans and animals.Numerous studies have confirmed that exopolysaccharides(EPSs)have various biological functions,but the mechanism through which EPSs improve the immunity of animals against the invasion of pathogenic bacteria is unclear.Here,we explored the protective effect of EPSs of Lactobacillus rhamnosus GG(LGG)on the S.T-infected intestine.Methods Mice received adequate food and drinking water for one week before the start of the experiment.After 7 d of prefeeding,2×108 CFU/mL S.T solution and an equivalent volume of saline(control group)were given orally for 1 d.On the fourth day,the mice were treated with 0.5 mg/mL EPSs,1.0 mg/mL EPSs,2.0 mg/mL EPSs,or 2.0 mg/mL penicillin for 7 d.Finally,the body and relative organ weight,histological staining,and the levels of antioxidant enzyme activity and inflammatory cytokines were determined.Results The S.T-infected mice exhibited symptoms of decreased appetite,somnolence,diarrhea and flagging spirit.Treatment with EPSs and penicillin improved the weight loss of the mice,and the high dose of EPSs showed the best therapeutic effect.EPSs significantly ameliorated S.T-induced ileal injury in mice.High-dose EPSs were more effective than penicillin for alleviating ileal oxidative damage induced by S.T.The mRNA levels of inflammatory cytokines in the ileum of mice showed that the regulatory effects of EPSs on inflammatory cytokines were better than those of penicillin.EPSs could inhibit the expression and activation of key proteins of the TLR4/NF-κB/MAPK pathway and thereby suppress the level of S.T-induced ileal inflammation.Conclusions EPSs attenuate S.T-induced immune responses by inhibiting the expression of key proteins in the TLR4/NF-κB/MAPK signaling pathway.Moreover,EPSs could promote bacterial aggregation into clusters,which may be a potential strategy for reducing the bacterial invasion of intestinal epithelial cells.

Exopolysaccharides from Marine Bacteria

Microbial polysaccharides represent a class of important products of growing interest for many sectors of indus- try. In recent years, there has been a growing interest in isolating new exopolysaccharides (EPSs)-producing bacteria from marine environments, particularly from various extreme marine environments. Many new marine microbial EPSs with novel chemical compositions, properties and structures have been found to have potential applications in fields such as adhesives, textiles, Pharmaceuticals and medicine for anti-cancer, food additives, oil recovery and metal removal in mining and indus- trial waste treatments, etc This paper gives a brief summary of the information about the EPSs produced by marine bacteria, including their chemical compositions, properties and structures, together with their potential applications in industry.

Antioxidant Activities of Exopolysaccharides Produced by Lactic Acid Bacteria Isolated from Commercial Yoghurt Samples

An antioxidant is a substance that inhibits the oxidation of other molecules caused by free radicals. The inbuilt antioxidant systems possessed by living organisms are generally not enough to prevent them from oxidative damages and the uses of synthetic antioxidants also have some harmful effects. This study was aimed at evaluating the antioxidant activities of exopolysaccharides produced by lactic acid bacteria isolated from yoghurt. Lactic acid bacteria (LAB) were isolated from six different brands of commercially available yoghurt using deMan Rogosa Sharpe (MRS) agar. The LAB isolates were identified based on morphological and biochemical analyses and were screened for exopolysaccharide (EPS) production. The LAB isolates screened positive were used for EPS production in a liquid medium and the EPS produced were purified and quantified using standard methods. Antioxidant activities of the EPS were evaluated by determining the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, ferric ion reducing power, and total phenolic contents. Data obtained were analysed using Analysis of Variance. Total lactic acid bacterial count obtained from the yoghurt samples ranged from 0 - 3.9 × 104 CFU/mL with sample A (Fan Yoghurt) having the highest LAB count (3.9 × 104 CFU/mL). The isolated LAB and their incidence rate were Lactobacillus plantarum (25.49%), L. delbrueckii (19.61%), L. fermentum (15.69%), L. acidophilus (13.73%), Leuconostoc mesenteroides (11.76%), Lactococcus lactis (7.84%), and Lactobacillus casei (5.88%). Fifty-one out of the 64 LAB isolates were screened positive for EPS production and only six were able to produce substantial quantity of EPS ranging from 127.4 - 208.5 mg/L. The exopolysaccharides produced by L. fermentum had the highest DPPH radical scavenging activity (62.90%) while that of L. plantarum had the lowest (23.10%) at a concentration of 1000 μg/mL. Also, the EPS produced by L. fermentum recorded the highest ferric ion reducing power (12.89 mg AAE/mL) at 1000 μg/mL while that of L. plantarum had the lowest (5.62 mg AAE/mL). At 1000 μg/mL, the total phenolic contents of the EPS samples ranged from 1.41 - 1.58 mg GAE/mL, and the EPS produced by L. fermentum had the highest (1.58 mg GAE/mL) while those produced by L. paracasei had the lowest (1.41 mg GAE/mL). This study revealed that the exopolysaccharides produced by the LAB isolates showed high antioxidant activities with respect to their DPPH free radical scavenging activity, ferric ion reducing power and total phenolic contents.

Exopolysaccharides Produced from <i>Lactobacillus delbrueckii</i>subsp. <i>bulgaricus</i>

Lactobacillus delbrueckii subsp. bulgaricus, which has been widely used as a fermented milk starter, is a type of probiotic, and certain strains are able to produce exopolysaccharide (EPS). EPS produced from L. bulgaricus contributes to the physical and biological function of dairy products by regulating immune response, and this tendency seems to place EPS with acidic groups. To date, six types of chemical structure have been determined and are basically composed from glucose (Glc), galactose (Gal), and rhamnose (Rha). Eps clusters on chromosome DNA control the EPS synthesis and are transcribed as one mRNA 14 genes with 18kb on L. bulgaricus Lfi5. Furthermore, L. bulgaricus is able to utilize lactose (Lac) as carbohydrate source, repeating units of EPS are synthesized from Glc 6-phosphate, generated by an Embden-Meyerhof (EM) pathway in cellular carbohydrate assimilation. This review discusses EPS produced from L. bulgaricus.

Studies on the optimal culture conditions of <i>Aureobasidium pullulans</i>to produce exopolysaccharides

In the current study, in order to change the permeability of cell membrane and solve the problem of linked group of fungi mycelium, the method of adjusting osmotic pressure of medium and adding tween-80 was established. The utilized strain with relatively high exopolysaccharide (EPS) yield and low pigment level was obtained after the rejuvenation and sifting of long-preserved Aureobasidium pullulans strain. The optimal proportion of substrate was determined by means of orthogonal test. The transformation ratio of EPS was increased by 10% - 20% and the pigment content was greatly reduced. The fermenting liquor is between creamy white and pale yellow, and the white primary product can be gained without decolourization step. Furthermore, to magnify to 5 L bioreactor can get the similar result.

Potential Application of Exopolysaccharides from Lactobacillus delbrueckii FASHADFF1 (LDYG2) and Weissella confusa FASHADFF1 (WCFF1) in Sourdough Bread Production

Baking of sourdough is a common practice and has the advantage of improving the nutritional value, sensory qualities and increasing the shelf life of the bread. This study therefore focus on the antimicrobial and antioxidant capacity of exopolysaccharides form Lactic Acid Bacteria (LAB) and its application in sourdough production. The Lactobacillus delbrueckii LDYG2 and Weissella confusa WCFF1 were collected from the culture collection Centre and the LABs were maintained in De Man, Rogosa and Sharpe (MRS) broth. Modified Exopolysaccharide Selection Medium (mESM) was used to produce the EPS while the total sugar concentration was determined using phenol-sulfuric acid method. The antibacterial, antioxidant, proximate, physical, organoleptic properties and the shelf life of the SDB produced were also evaluated. The quantity of EPS produced by LDYG2 and WCFF1 ranged from 4743.75 - 5090.03 g/L. Eight different sugars were present in both EPSLD and EPSWC with high antibacterial activity (24 mm and 23 mm) against B. cereus and S. aureus respectively. EPSLD and EPSWC had antioxidant capacity increased in a dose dependent (0.5 - 10 mg/mL) manner. EPSWCSDB had the highest proximate content except for moisture content. There was a significantly different (P ≤ 0.05) in the shelf life extension of the sourdough bread. WCEPSSDB was generally accepted in terms of colour, aroma, taste, texture and palatability. EPS produced by L. delbrueckii (EPSLD) and W. confusa (EPSWC) has antimicrobial and antioxidant capacity and can be used in production of nutraceutical sourdough bread with an improved shelf life and high consumer acceptability.

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

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

Prospecting Exopolysaccharides Produced by Selected Bacteria Associated with Marine Organisms for Biotechnological Applications

In this study, bacteria associated with marine organisms were screened for the production of exopolysaccharides（EPSs） on MY media containing sea salts（2.5%-10%）. Three selected isolates were identified as Alteromonas sp. PRIM-21, Nitratireductor sp. PRIM-24 and Enterobacter sp. PRIM-26 using 16 S r RNA gene sequencing. Optimization of the growth and EPS production kinetics in relation to incubation time were assessed. The purified EPS yield was 590, 650 and 540 mg·L-1 culture media respectively in Alteromonas sp. PRIM-21, Nitratireductor sp. PRIM-24 and Enterobacter sp. PRIM-26. Biochemical and FTIR analyses revealed the presence of biologically important functional groups in the EPS produced by all the three isolates. The EPS produced by Nitratireductor sp. PRIM-24 and Alteromonas sp. PRIM-21 showed 2.0% sulfate content. These bacterial EPS also showed antioxidant and emulsifying activities and the EPS produced by Enterobacter sp.PRIM-26 showed significantly higher antioxidant activities in terms of superoxide（IC50 0.33 mg·mL -1） and DPPH（IC50 0.44 mg·mL -1） radical scavenging. It also showed higher emulsifying activities against selected hydrophobic substrates with EI24 values above 60%. From the results of the study, it can be concluded that the isolated bacteria produce EPS that can be investigated in detail for biotechnological applications.

Identification of Anamorph Yeast of Tremella aurantialba and Optimization of Medium Composition for Production of Exopolysaccharides

A yeast-like fungus strain B1 isolated from wild fungus Tremella aurantialba was identified and initially characterized. Two phylogenetic trees were generated based on the sequences of large subunit ribosomal RNA gene D1/D2 regions and internal transcribed spacer (ITS) regions of related fungi, respectively. The analysis of D1/D2 regions and ITS sequences showed that fungus B1 was clustered together with T. aurantialba, T. aurantia and T. microspore in the phylogenetic trees. Both the morphological characteristic and phylogenetic analysis established that fungus B1 was one of the anamorph strains of T. aurantialba and belongs to Tremella genus. A fermentation medium for exopolysaccharides (EPS) production by T. aurantialba B1 . Plackett-Burmen design was used to evaluate the effects of different components in the culture medium. Glucose and yeast extract have significant influence on the EPS production. The concentrations of two factors were optimized subsequently using central composite design and response surface analysis. The results showed that 49.2 g/L glucose and 10.4 g/L yeast extract could lead to the maximum production of EPS (4.99 g/L). The optimized medium led to a 1.5-fold enhancement of the production of EPS by T. aurantialba B1 , as compared with that without optimization.

White-rot Fungus Growth Conditions and Its Metabolic Kinetic Models

To investigate the growth conditions of white-rot fungus and simulate its metabolism kinetic models, the rules how the factors such as biomass, culture fluid, pH value, glucose consumption and exopolysaccharides generation, etc., changed during the batch culture process of white-rot fungi by using an air-lift fermenter, as well as metabolic kinetics of white-rot fungi were studied. Based on Logistic equation, Luedeking-Piret equation and experimental data, the correlation model parameters of mycelia biomass, glucose consumption and exopolysaccharide generation were obtained and found to be change with time in metabolism process. Detailedly, μm=0.071 8 h-1,α= 0.831 8 g/(g·h), β= 0.002 g/(g·h), b1=0.016 3 g/(g·h) and b2=3.023 3 g/(g·h). Hence the mycelial growth kinetic model, exopolysaccharide generation kinetic model and substrate consumption kinetic model which describe fermentation process of white-rot fungi were established. Meanwhile, the experimental data were verified by this model, and a good fitting result with an average relative error less than 10% between the data obtained from experiments and the model was yielded. The results show that these models can predict the growth and metabolic rules of white-rot fungus, the fermentation process of exopolysaccharides and the kinetic mechanism of white-rot fungus accurately.

Therapeutic effect of Streptococcus thermophilus CRL 1190-fermented milk on chronic gastritis

AIM: To investigate the potential therapeutic effect of exopolysaccharide (EPS)-producing Streptococcus thermophilus (S. thermophilus) CRL 1190 fermented milk on chronic gastritis in Balb/c mice. METHODS: Balb/c mice were fed with the fermented milk for 7 d after inducing gastritis with acetyl-salicylic acid (ASA, 400 mg/kg body weight per day for 10 d). Omeprazole was included in this study as a positive therapeutic control. The gastric in? ammatory activity was evaluated from gastric histology and in? ammation score, number of interleukin-10 (IL-10), interferon-γ (INFγ) and tumor necrosis factor-α (TNF-α) cytokine-producing cells in the gastric mucosa, and thickness of the mucus layer. RESULTS: Animals receiving treatment with the EPS-producing S. thermophilus CRL 1190 fermented milk showed a conserved gastric mucosa structure similar to that of healthy animals. In? ammation scores of the fermented milk-treated mice were lower than those of mice in the gastritis group (0.2 ± 0.03 vs 2.0 ± 0.6, P < 0.05). A marked decrease in INFγ+ (15 ± 1.0 vs 28 ± 1.2, P < 0.05) and TNF-α+ (16 ± 3.0 vs 33 ± 3.0, P < 0.05) cells and an increase in IL-10+ (28 ± 1.5 vs 14 ± 1.3, P < 0.05) cells compared to the gastritis group, was observed. Also, an increase in the thickness of the mucus gel layer (2.2 ± 0.6 vs 1.0 ± 0.3; 5.1 ± 0.8 vs 1.5 ± 0.4 in the corpus and antrum mucosa, respectively, P < 0.05) compared with the gastritis group was noted. A milk suspension of the purif ied EPS from S. thermophilus CRL1190 was also effective as therapy for gastritis.

Biofilm three-dimensional architecture influences in situ pH distribution pattern on the human enamel surface

To investigate how the biofilm three-dimensional(3D) architecture influences in situ pH distribution patterns on the enamel surface. Biofilms were formed on human tooth enamel in the presence of 1% sucrose or 0.5% glucose plus 0.5% fructose. At specific time points, biofilms were exposed to a neutral pH buffer to mimic the buffering of saliva and subsequently pulsed with 1% glucose to induce re-acidification. Simultaneous 3D pH mapping and architecture of intact biofilms was performed using two-photon confocal microscopy. The enamel surface and mineral content characteristics were examined successively via optical profilometry and microradiography analyses. Sucrose-mediated biofilm formation created spatial heterogeneities manifested by complex networks of bacterial clusters(microcolonies). Acidic regions(pH<5.5) were found only in the interior of microcolonies,which impedes rapid neutralization(taking more than 120 min for neutralization). Glucose exposure rapidly re-created the acidic niches, indicating formation of diffusion barriers associated with microcolonies structure. Enamel demineralization(white spots),rougher surface, deeper lesion and more mineral loss appeared to be associated with the localization of these bacterial clusters at the biofilm-enamel interface. Similar 3D architecture was observed in plaque-biofilms formed in vivo in the presence of sucrose. The formation of complex 3D architectures creates spatially heterogeneous acidic microenvironments in close proximity of enamel surface, which might correlate with the localized pattern of the onset of carious lesions(white spot like) on teeth.

Nutrient Requirements and Fermentation Conditions for Mycelia and Crude Exo-Polysaccharides Production by <i>Lentinus squarrosulus</i>

Lentinus squarrosulus Mont. is an emerging tropical white rot basidiomycete, with nutritional and medicinal benefits. Low levels of commercial cultivation of the mushrooms limit their availability for use as food and medicine. Mycelia from submerged fermentation are a suitable alternative to the mushroom from L. squarrosulus. Three strains, 340, 339 and 218, were studied to determine optimum growth conditions for mycelia mass and crude exo-polysaccharides (CEPS) production. The experiments were conducted in a completely randomized design (CRD) with a factorial structure. Nutrients involving 8 carbon and 8 nitrogen sources were screened, and concentrations of the best sources were optimized. Optimized nutrients, interaction between strains and other parameters such as agitation and medium volume were investigated to obtain optimum fermentation conditions for biomass and CEPS production. Biomass yield varied among strains depending on carbon or nitrogen nutrient sources. Starch and yeast extract at 30 and 25 g/L were identified as the most important nutrients in mycelia and CEPS production. Nutrient optimization resulted in a 3-fold increase in mycelia mass: 12.8, 10.0 and 15.3 g/L in strains 340, 339 and 218 respectively. There was a significant interaction between strain, agitation, and volume (p p = 0.02). Static conditions favored more polysaccharide production. Optimized fermentation conditions resulted in very high increase in biomass: 238.1, 266.9 and 185.0 g/L in strains 340, 339 and 218 respectively. Results obtained could be useful in modeling fermentation systems for large-scale production of mycelia mass, CEPS and other bio-products from L. squarrosulus.

Azospirillum brasilense and Saccharomyces cerevisiae as Alternative for Decrease the Effect of Salinity Stress in Tomato(Lycopersicon esculentum)Growth

The salinity stress is one of the most relevant abiotic stresses that affects the agricultural production.The present study was performed to study the improvement of the salt tolerance of tomato plants which is known for their susceptibility to salt stress.The present study aimed to assess to what extent strain Azospirillum brasilense(N040)and Saccharomyces cerevisiae improve the salt tolerance to tomato plants treated with different salt concentration.The inoculant strain A.brasilense(N040)was previously adapted to survive up to 7%NaCl in the basal media.A greenhouse experiment was conducted to evaluate the effect of this inoculation on growth parameter such as:plant height,root length,fresh and dry weight,fruits fresh weight,chlorophyll content,proline and total soluble sugar in tomato plants under salt stress condition.The results revealed that co-inoculation of Azospirillum brasilense(N040)and Saccharomyces cerevisiae significantly increased the level of proline(8.63 mg/g FW)and total soluble sugar(120 mg/g FW)of leaves under salinity condition comparing to non-inoculated plants(2.3 mg/g FW and 70 mg/g FW,respectively).Plants co-inoculated with adapted strain of A.brasilense and S.cerevisiae showed the highest significant(p<0.01)increase in fruit yield(1166.6 g/plant),plant high(115 cm)and roots length(52.6)compared whit un-inoculated control plants(42 g/pant,43.3 cm and 29.6 cm,respectively).In contrast,Na^(+)ion content was significantly decreased in the leaves of salt stressed plants treated with the A.brasilense(N040)and S.cerevisiae.Finally,the results showed that dual benefits provided by both A.brasilense(N040)and S.cerevisiae can provide a major way to improve tomato yields in saline soils.

Production, Detection and Cross-Reactivity of Anti-Polysaccharide Antibodies from Environmental Fungi

The diagnosis of Invasive Fungal Disease (IFD) is difficult because the sensitivity of conventional culture and cytology methods for the detection of Aspergillus is poor, and because serological methods exhibit cross-reactivity with environmental fungi. Fungal polysaccharides are of particular interest in the serologic diagnosis of IFD, especially galactomannan (GM) and glucan, which have been recognized as useful tools for the diagnosis of fungal infections. Further investigation into polysaccharide antibody cross-reactivity is important in improving diagnostic tests. Our aim was to verify the production of antibodies against fungal antigens in mice immunized with exopolysaccharides (EPS) obtained from three fungal species (Aspergillus terreus, Paecilomyces variotii and Curvularia brachyspora). ELISA assays were performed to evaluate homologous and heterologous reactions and showed anti-polysaccharide antibodies production. EPS from A. terreus was immunogenic enough to immunize the animal and lead to antibody production against this EPS. In addition, no cross-reactivity was observed with EPS obtained from P. variotii and C. brachyspora. The EPS from P. variotii did not exhibit good immunogenicity, whereas EPS from C. brachyspora showed good immunogenicity, and heterologous reactions were detected on the ELISA assays performed using the EPS from this species. The results indicate that immunization can occur for environmental fungal polysaccharides, generating antibodies may be interfere in serological diagnosis that are based on detection of fungal polysaccharides, mainly glucans and galactomannans.

Extracellular Polymeric Substance (EPS) Production by Nostoc minutum under Different Laboratory Conditions

A study of the influence of different laboratory growth conditions on the biomass and EPS production by Nostoc minutum, a diazothophic cyanobacterium locally isolated, was carried out. Two culture media were tested, with or without NaNO3 addition, and three luminous intensities: low (4530 lux), intermediate (7300 lux) and high (9860 lux). BW3 medium was better than BG11 for N. minutum growth, with maximal values of biomass concentration (4.98 DO) and the highest growth rate (0.019 h-1) at 9860 lux of light intensity. A progressive increase in culture viscosity of N. minutum cultures was observed, for stirred condition and non-diazotrophic growth in BG11 medium, together with the production of maximal EPS concentration (2.485 g/L). On the other hand, the EPS production in BW3 medium was maximal in diazotrophic conditions, both for still (1.66 g/L) and stirred (2.56 g/L) cultures. The different yields of EPS reported for each condition, results in the requirement of a species-specific optimization of the cultivation conditions for the exploitation of an efficient technology for the production of N. minutum EPS.

A New Pullulan-Producing Yeast and Medium Optimization for Its Exopolysaccharide Production

Yeast strain Y68 producing high level of pullulan was isolated from the phyton collected in Toulouse, France. This strain was identified to be Rhodotorula bacarum by BIOLOG analysis. This is the first report that pullulan was produced by Rhodotorula bacarum. The optimal medium (g L -1) for pullulan production by this strain was 80 glucose, 20 soybean cake hydrolysate, 5 K 2HPO 4, 1 NaCl, 0.2 MgSO 4·7H 2O, 0.6 (NH 4) 2SO 4, pH 7.0. Under this condition, 54 g L -1 pullulan was produced within 60 h at 30 ℃. Pullulan is a better starting material for producing marine prodrugs.

Structural Characterization of Glucan Produced by Lactobacillus sake L-7 from Sausage

A linear glucan was produced by Lactobacillus sake L-7 isolated from homemade sausage. Cultivation of the strain in Man–Rogosa–Sharpe(MRS) medium containing 50 g/L sucrose yielded 5.3 g/L of purified exopolysaccharide(EPS). The EPS was characterized by gas chromatography(GC), Fourier-transform infrared(FT-IR) spectroscopy, high-performance sizeexclusion chromatography(HPSEC), nuclear magnetic resonance(NMR) spectroscopy, and scanning electron microscopy(SEM). The monosaccharide composition of the EPS was glucose, and its molecular weight was 1 × 10~7 Da. The FT-IR and NMR spectra revealed that the L-7 EPS was a linear glucan with α-(1 → 6) glucosidic bonds. SEM images of the dried EPS revealed a hollow tubular structure. The water solubility index and water holding capacity of L-7 EPS were 96 and 272%, respectively. The results of hydrolysis indicated that L-7 EPS was not susceptible to hydrolysis by physiological barriers and can be used as a soluble dietary fiber with health benefits. All these characteristics suggest that L-7 EPS might have potential applications in the food, cosmetic, and pharmaceutical industries.

Production and characterization of insoluble α-1,3-linked glucan and soluble α-1,6-linked dextran from Leuconostoc pseudomesenteroides G29

Exopolysaccharides can be produced by various bacteria and have important biological roles in bacterial survival depend on molecular weight,linkage,and conformation.In this study,Leuconostoc pseudomesenteroides G29 was identified and found to produce two types of exopolysaccharides from sucrose including soluble and insoluble a-glucans.By regulation of pH above 5.5,soluble a-glucan production was increased to 38.4 g∙L^(-1) from 101.4 g∙L^(-1) sucrose with fewer accumulation of lactic acid and acetic acid.Simultaneously,the quantity of thick white precipitate,that is insoluble a-glucan,was also increased.Then,a-glucans were prepared by enzymatic reaction with crude glucansucrases from the supernatant of G29 fermentation broth and purified for structure analysis.Based on the integration analysis of FT-IR and NMR,it was observed that soluble a-glucan is a highly linear dextran with α-1,6 glycosidic bonds while the insoluble a-glucan has 93%of α-1,3 and 7%of α-1,6 glycosidic bond.The results extend our understanding of exopolysaccharides production by L.pseudomesenteroides,and this water insoluble α-1,3-glucan might have potential application as biomaterials and/or biochemicals.

Production,characterization and biological activities of acidic exopolysaccharide from marine Bacillus amyloliquefaciens 3MS 2017

Objective: To evaluate in-vitro antioxidant, anti-inflammatory and antitumor abilities against human breast adenocarcinoma(MCF7) and human prostate cancer(PC3) as well as the suppressor effect of bacterial exopolysaccharide(BAEPS) on Ehrlich ascites carcinoma(EAC). Methods: In-vitro antioxidants characters of BAEPS were determined using various methods, while anti-inflammatory activity was estimated against cyclooxygenase(COX-1 and COX-2). In-vitro study, anticancer against MCF7 and PC3 were assessed by the mitochondrial dependent reduction of yellow MTT. In in-vivo study against EAC progression, mice were inoculated with EAC cells and then were orally administered BAEPS at 200 mg/kg after 24 h(equals to 0.10 of determined LD50)/10 d. Results: BAEPS was acidic exopolysaccharide contained uronic acid(12.3%) and sulfate(22.8%) with constitution of glucose, galactose and glucuronic acid in a molar ratio1.6: 1.0: 0.9, respectively, with a molecular mass of 3.76伊104 g/mol. BAEPS appeared potent antioxidant characters as free radical scavenging, oxygen reactive species scavenging and metal chelation, while its reducing power was low. BAEPS showed selective anti-inflammatory activity against COX-2 than COX-1, COX-2 selective. BAEPS exhibited potent and selective effect to breast cell cancer MCF7, the death percentage was 65.20% with IC_(50)=70 μg/m L and IC_(90)=127.40 μg/m L. BAEPS decreased counted viable EAC cells and induced non-viable cells. BAEPS improved all assessed hematological parameters. These improvements were reflected in the increasing median survival time and significant increment(P<0.05) in life span. Conclusions: BAEPS has anti-tumor activity with a good margin of safety. The anti-tumor activity of BAEPS may be due to its content from sulfated groups and uronic acids and they have antioxidant and anti-inflammatory properties.