Crude Extracellular Polysaccharides Research Articles

Structural insight into a glucomannan-type extracellular polysaccharide produced by a marine Bacillus altitudinis SORB11 from Southern Ocean

Extracellular polysaccharide (EPS) produced by a deep-sea, psychrotolerant Bacillus altitudinis SORB11 was evaluated by considering physiochemical nature and structural constituents. The productivity of crude EPS was measured ~ 13.17 g L−1. The surface topography of the crude EPS showed a porous, webbed structure along with a branched coil-like configuration. The crystalline crude EPS contained a high amount of sulfur. Further, the crude EPS was subjected for purification. The molecular weight of purified EPS was determined ~ 9.8 × 104 Da. The purified EPS was appeared to show glucomannan-like configuration that is composed of → 4)-β-Manp-(1 → and → 4)-β-Glcp-(1 → residues. So, this polysaccharide was comparable to the structure of plant-derived glucomannan. Subsequently, EPS biosynthesis protein clusters like EpsC, EpsD, EpsE, and glycosyltransferase family proteins were predicted from the genome of strain SORB11, which may provide an insight into the production of glucomannan-type of polysaccharide. This low molecular weight linear form of glucomannan-type EPS might be involved to form a network-like unattached aggregation, and helps in cell-to-cell interaction in deep-sea microbial species.

Structural features of the bioactive cyanobacterium Nostoc sp. exopolysaccharide

Microalgal biopolymers are studied mainly in terms of physico-chemical characterization, biological effects as well as possible biotechnological applications. Due to the significant antitussive, bronchodilator, anti-inflammatory and immunomodulatory effects of the previously isolated crude extracellular polysaccharide (EPS) produced by the cyanobacterium Nostoc sp., the purified biopolymer and its oligosaccharides, obtained after partial acid hydrolysis, were subjected to an in-depth NMR structural study. Analyses of the data obtained by chemical methods and NMR showed that the EPS backbone is composed of the repeating unit [→4)-β-D-Xylp-(1 → 4)-β-D-Glcp-(1 → 4)-α-L-Arap-(1 → 3)-β-D-Manp-(1→]n, in which about 60% of glucose units are substituted at C6 by uronic acids, in particular by the unusual unsaturated 3-O-lactyl-4-deoxy-α-erythro-hex-4-enopyranuronic acid, and to a lesser extent by β-D-glucuronic acid and 3-O-lactyl-β-D-glucuronic acid. These findings, structural features and identified biological effects, suggest the potential use of this biopolymer in the medical-pharmaceutical field.

Structural Analysis and Antioxidant Activity of Extracellular Polysaccharides Extracted from Culinary-Medicinal White Jelly Mushroom Tremella fuciformis (Tremellomycetes) Conidium Cells.

Using Tremella fuciformis conidium cells for submerged fermentation is a cost-effective way to harvest bioactive compounds. In this study, we emphasized the structural and functional analysis of extracellular polysaccharides (EPS) extracted from T. fuciformis conidium cells. An EPS high-yield strain tyc63 was selected and a 6-day optimum fermentation period was determined. Crude EPS was extracted and three high molecular weight (5189, 171.6, and 661 kDa) polysaccharides TFP-1, TFP-2, and TFP-3 were isolated and purified. TFP-1 is mainly composed of glucose, xylose, mannose, and fucose, while both TFP-2 and TFP-3 are mainly composed of rhamnose, arabinose, mannose, galactose, and glucose. FT-IR analysis revealed that TFP-1, TFP-2, and TFP-3 have typical polysaccharide structure. The antioxidant assay revealed that the crude EPS, TFP-1, TFP-2, and TFP-3 presented high free radical scavenging activities but low ferric reducing power, suggesting that the EPS produced by liquid fermentation could be used as a potent radical scavenger.

Extracellular polysaccharide from Ralstonia solanacearum; A strong inducer of eggplant defense against bacterial wilt

Ralstonia solanacearum a phytopathogenic bacterium produces virulence factor via production of extracellular polysaccharides (EPS). We have isolated EPS from R. solanacearum and characterized this by AFM, SEM, FTIR, LC-MS and NMR spectroscopy. Interestingly, the result showed pore size distribution, topology, rheological and pseudoplastic behaviour of EPS and three major monosaccharides, glucuronic acid, N-acetylglucosamine and glucose associated with EPS. Eggplant treated with intact crude EPS showed a significant 51% decrease in bacterial wilt incidence for both in vitro and greenhouse conditions. In eggplant cultivars EPS induces significant up-regulation of guaiacol peroxidase and ascorbate peroxidase defense genes, providing screen resistance against bacterial wilt.

Bioprospecting of Traditional Sweet Manufacturing Effluent for Exopolysachharide Producing Bacteria and Their Biotechnological Applications

This work was aimed to isolate, purify, characterize and to study the biological applications of extracellular polysaccharide (EPS) produced by Agrobacterium fabrum strain C 58 isolated from effluent of a traditional sweet manufacturing unit. The isolated bacterium Agrobacterium fabrum strain C 58 was found to produce 16.21 g/L crude EPS in terms dry weight at 28 0C when brown sugar was supplemented as the source of carbon. The polysachharide was further purified by anion exchange chromatography on a column of DEAE Cellulose -52 yielding one fraction which eluted at 0.2M NaCl. The monosachharide composition of EPS by TLC indicated it to be a hetero polysachharide composed of glucose, galactose, mannose and rhamnose. The FT-IR analysis proves the presence of biologically important functional groups and alpha glycosidic linkage between individual glycosyl residues. The biopolymer at a concentration of 1 % exhibited significant lipid emulsifying capacity against various vegetable oils. The effectiveness of polysaccharide in inhibiting free radicals evaluated by DPPH radical scavenging appeared to be significant. This is the first report about isolation of potent EPS producers from a traditional sweet manufacturing unit effluent which confirms that these samples can be used as a potential habitat for bioprospecting extracellular polymer producing bacteria. The diversity offered by microorganisms in these diverse habitats thus renders a hope for screening new habitats for isolating and developing new polysaccharides with properties superior to those of the existing polymers.Int J Appl Sci Biotechnol, Vol 3(3): 520-527

Biochemistry of TBT-Degrading Marine Pseudomonads Isolated from Indian Coastal Waters

Tributyltin (TBT) is a very effective biocide and an active ingredient in antifouling paints. Screening along the Indian coast yielded 49 bacterial isolates capable of TBT assimilation. The screening was done based on the ability of bacteria to grow in mineral salt medium (MSM) containing TBT as the sole source of carbon. All the isolates produced exopolysaccharides (biosurfactants) in the medium which aid in emulsification and thus ease bioavailability of TBT. Five isolates were identified as potent TBT degraders (namely, Pseudomonas pseudoalcaligenes, Pseudomonas stutzeri, Pseudomonas mendocina, Pseudomonas putida, and Pseudomonas balearica) based on their biomass production in MSM containing TBT as the sole source of carbon. In addition to evaluating the potential of individual bacterial strains, the study also focused on using a consortium of bacteria to explore their synergistic effect when grown on TBT. Further tests like growth profile, rhamnolipid secretion profile, extracellular protein secretion profile, and detection of siderophores were performed on these isolates when grown in MSM supplemented with 2 mM TBT concentration. Emulsification activity of the crude extracellular polysaccharides against kerosene was evaluated. It can be therefore inferred that TBT degradation by these marine pseudomonads is a two-step process: (a) dispersion of TBT in the aqueous phase and (b) tin–carbon bond cleavage by siderophores affecting debutylation of TBT. The consortium of bacteria may be effective in the treatment of TBT-contaminated waste water in dry docks.

Hypoglycemic effect of polysaccharides produced by submerged mycelial culture of Laetiporus sulphureus on streptozotocininduced diabetic rats

The hypoglycemic effect of the crude extracellular polysaccharides (EPS) produced from submerged mycelial culture of an edible mushroom Laetiporus sulphureus var. miniatus in streptozotocin (STZ)-induced diabetic rat was investigated. Hypoglycemic effect of EPS was evaluated in STZ-induced diabetic rats, and its possible mechanism was suggested by the results of western blot analysis and immunohistochemical staining. The results revealed that orally administrated EPS, when given 48 h after STZ treatment exhibited an excellent hypoglycemic effect, lowering the average plasma glucose level in EPS-fed rats to 43.5% of STZ-treated rats. The plasma levels of total cholesterol and triglyceride were significantly increased upon STZ treatment and they were markedly reduced by oral administration of EPS to near-normal levels. The results of immunohistochemical staining of the pancreatic tissues showed that EPS treatment considerably increased the insulin antigenesity of diabetic islet β-cells, suggesting the possibility of β-cell proliferation or regeneration by EPS therapy. Moreover, immunoblotting study revealed that protein levels of iNOS was increased and SOD2, catalase, GPx were significantly increased after EPS treatments, suggesting alleviated oxidative stress mediated by STZ. Orally administrated EPS exhibited considerable hypoglycemic effect in STZ-induced diabetic rats and that these EPS may be useful for the management of diabetes mellitus.

Isolation and antioxidant property of the extracellular polysaccharide from Rhodella reticulata

The extracellular polysaccharide from Rhodella reticulata was separated from the culture medium followed by concentration and ethanol precipitation, and purified by anion exchange chromatography on DEAE-Sepharose Fast Flow. This study compared the free radical-scavenging property and antioxidant activity with various treatments of crude extracellular polysaccharides of R. reticulata. The results showed that both the crude extracellular polysaccharide and deproteinized crude extracellular polysaccharide gave evidence of the free radical scavenging and antioxidant activity in a dose-dependent manner. The crude extracellular polysaccharide exhibited higher free radical scavenging capacity and better antioxidant activity than the various treatments of crude extracellular polysaccharide samples. The superoxide anion radical scavenging ability of various samples was significantly higher compared to standard antioxidant (α-tocopherol). These results indicate that the extracellular polysaccharide of R. reticulata is a potent natural antioxidant.

Tumor-inhibitory and liver-protective effects of Phellinus igniarius extracellular polysaccharides

The tumor-inhibitory and liver-protective effects of crude extracellular polysaccharides (EPS) extracted from the liquid mycelial culture of the mushroom Phellinus igniarius were studied in mice. The mice were injected with murine sarcoma S180 and murine hepatoma H22. Crude EPS at 100, 200, 400 mg kg−1 body weight was administered to EPS groups each day in the twelve consecutive days. The result showed that EPS 200 mg kg−1 body weight significantly inhibited S180 and H22 at 65.0 and 46.3%, respectively. Moreover, EPS could not only keep the numbers of WBC, RBC, PLT and the concentration of HGB in a normal range, but also normalize the activities of AST, ALT and ALP. For example, in EPS-treated mice, AST significantly reduced with the percentage of A/G reverse in S180 (P < 0.05) and H22 (P < 0.01) when the mice took EPS 200 mg kg−1 body weight. In conclusion, it was remarkable that P. igniarius EPS exhibited antitumor activity related to dosage and protected liver function by sustaining the blood routine as well as keeping the blood biochemical indexes normal.

Immunomodulatory Effects of Polysaccharides Produced by Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1

The extracellular polysaccharides (EPS) produced by lactic acid bacteria (LAB) are associated with the rheology, texture, and mouthfeel of fermented milk products, including yogurt. This study investigated the immunomodulatory effects of EPS purified from the culture supernatant of Lactobacillus delbrueckii ssp. bulgaricus (L. bulgaricus) OLL1073R-1. The crude EPS were prepared from the culture supernatant of L. bulgaricus OLL1073R-1 by standard chromatographic methods, and were fractionated into neutral EPS and acidic EPS (APS). Acidic EPS were further fractionated into high molecular weight APS (H-APS) and low molecular weight APS (L-APS). High molecular weight APS were shown to be phosphopolysaccharides containing D-glucose, D-galactose, and phosphorus. Stimulation of mouse splenocytes by H-APS significantly increased interferon-γ production, and, moreover, orally administered H-APS augmented natural killer cell activity. Oral administration of yogurt fermented with L. bulgaricus OLL1073R-1 and Streptococcus thermophilus OLS3059 to mice showed a similar level of immunomodulation as H-APS. However, these effects were not detected following administration of yogurt fermented with the starter combination of L. bulgaricus OLL1256 and S. thermophilus OLS3295. We conclude from these findings that yogurt fermented with L. bulgaricus OLL1073R-1, containing immunostimulative EPS, would have an immunomodulatory effect on the human body.

Structure and antitumor activity of extracellular polysaccharides from mycelium

Two heteropolysaccharides coded as EPF1 and EPF2 were obtained from the crude extracellular polysaccharide (CEP) of Ganoderma tsugae mycelium by elution with DEAE-Sepharose CL-6B column. Their chemical structures and molecular mass were characterized by infrared, gas chromatography, 13C NMR and size exclusion chromatography combined with laser light scattering (SEC-LLS). The results indicated that they were mainly composed with mannose, fucose, xylose, galactose and glucosamine. EPF2 was confirmed to be mainly a β- d-galacto-α- d-mannan. The weight-average molecular mass of the samples EPF1, EPF2 and CEP were 92.0×10 4, 8.35×10 4 and 23.8×10 4, respectively. The EPF1 existed as a compact coil chain in 0.2 M NaCl aqueous solution at 25 °C, while EPF2 as a flexible chain. The antitumor activities against Sarcoma 180 were tested both in vitro and in vivo. All the samples exhibited high inhibition ratio against Sarcoma 180 in mice, and the CEP has higher inhibition effect both in vivo and in vitro than EPF1 and EPF2. In view of these results, the presence of bound protein and mannose, and relatively expanded chain would be helpful to the enhancement of antitumor activities. This study suggested that the extracellular polysaccharides had a potential application as natural antitumor drugs.

Heteropolysaccharide Formation by Arthrobacter viscosus Grown on Xylose and Xylose Oligosaccharides

Arthrobacter viscosus NRRL B-1973 produces its viscous extracellular polysaccharides (EPS) when grown on media containing xylose or enzymatic xylan hydrolysates. Crude EPS formation from xylose averaged 12 g/liter when initial culture pH was adjusted to 8.0 and total nitrogen was limited to 0.03%. Purified EPS from pentose and hexose substrates were analyzed for their monosaccharide, acetyl, and uronic acid components, intrinsic viscosities, and average molecular masses. Differences were apparent in degrees of acetylation, molecular masses, and intrinsic viscosities of the heteropolysaccharides produced on different carbon sources.

Levan and levansucrase synthesized by the fireblight pathogen Erwinia amylovora

The fireblight pathogen Erwinia amylovora synthesizes two different types of extracellular polysaccharide (EPS) when cultured in vitro, an acidic and a neutral compound. Neutral EPS was prepared from culture supernatants by cross-flow ultrafiltration and molecular washing, and purified by column chromatography. This material represented most of the crude EPS, which was produced in high-sucrose medium. It was entirely composed of fructose. The signals obtained from the EPS-preparation by 13C-NMR spectroscopy were identical with those of levan from Aerobacter levanicum indicating a β-2,6 linkage of the sugar residues. The neutral component of the EPS was thus identified as levan (β-2,6- d-fructofuranan). In the protein fraction associated with crude EPS, the levan polymerizing enzyme levansucrase (β-2,6- d-fructan: d-glucose 6-fructosyltransferase, EC 2.4.1.10) was detected. The enzyme was also produced at similar levels with several carbon sources by the bacterium. In polyacrylamide gel eletrophoresis its molecular weight under completely denaturating conditions was 46 kDa, when purified to apparent homogeneity by membrane-exchange chromatography. However, in isoelectric focussing, the enzyme preparation produced two bands at pI 4·0 and pI 3·6, respectively. Both bands displayed enzyme activity in an in situ levansucrase assay. Secretion of levansucrase may play an important role for multiplication of E. amylovora in sucrose containing plant tissue.

Studies on the Extracellular Polysaccharides (EPS) Produced in vitro by Pseudomonas phaseolicola III. Kinetics of Levan and Alginate Formation in Batch Culture and Demonstration of Levansucrase Activity in Crude EPS

AbstractIn batch culture Pseudomonas phaseolicola converted ca. 8–11% of the substrate (sucrose) into extracellular polysaccharides (EPS). The percentage of conversion was independent of the concentration of sucrose in the medium. However, the increase of total EPS observed with enhanced substrate concentration was largely due to a drastic stimulation of the levan produced. Production of alginate, in contrast, was stimulated to a much lower extent. EPS production was highest during the middle phaseof exponential growth and gradually terminated as the cultures grew older. With sucrose as substrate, the formation of alginate followed the levan synthesis. With glucose or gluconate, however, there was no production of levan, and the alginate synthesis, started immediately after the lag‐phase of the culture.Levansucrase activity was detected in the protein fraction of crude EPS produced by a culture grown in sucrose containing medium. Enzyme activity was demonstrated both by the release of glucose and the formation of levan from sucrose. Upon ion exchange chromatography on DEAE‐fractogel levansucrase behaved as a rather acidic protein. Native polyacrylamide gel electrophoresis of the enzyme fraction revealed a major band with an apparent molecular weight of ca. 68,000 d. Several grams of levan were synthesized with a partly purified enzyme preparation in the absence of bacteria.

Potential Microbial Utilization of Citrus Oil‐Mill Effluent

ABSTRACT Condida utilis (ATCC 9950) produced an average 0.21g protein per 100 mL citrus oil mill effluent while reducing the sugar content by 92.2% and the BOD by 33.8%. Limonene was removed from the effluent and sugars concentrated to 6.8% by membrane filtration. Saccharomyces cerevisiae (ATCC 4111) produced 3.0% ethanol by volume while reducing the sugar content 90.3% when grown in the concentrated effluent. Hansenula holstii (ATCC 13689) and Rhodosporidium toruloides (ATCC 10788) were grown in the concentrated effluent diluted to 2.7% sugars. Crude lipid produced by R. toruloides was 26.3% of the cell dry weight, while H. holstii produced 0.3 g crude extracellular polysaccharide per 100 mL.

Infectivity of Rhizobium meliloti as affected by extracellular polysaccharides

Olivares, J., Bedmar, E.J. &amp; Martinez‐Molina, E. 1984. Infectivity of Rhizobium meliloti as affected by extracellular polysaccharides. Journal of Applied Bacteriology56, 389–393.The addition of crude extracellular polysaccharide (EPS) preparations from highly infective Rhizobium meliloti increased the infectivity of a poorly infective strain. The addition of crude EPS preparations from another species did not promote nodu‐lation, suggesting the specificity of such an effect. Acid treatment of the crude EPS preparations resulted in total inhibition of nodulation.

Extracellular polysaccharide of Aspergillus flavus

A crude extracellular polysaccharide was isolated by precipitation with ethanol from the culture medium of Aspergillus flavus, where the sole carbon source was D-galactose; purification afforded a homogeneous water-soluble polysaccharide in 0.05% yield on the weight of the employed carbon source. This polysaccharide had the relative molar weight 55 000 and [α]D22 -4.2° (c 0.5, H2O); upon total hydrolysis it afforded D-mannose and D-galactose in a 1 : 0.44 ratio. The products of hydrolysis of the methylated polysaccharide and also the course of partial acid and enzymic hydrolyses of the polysaccharide showed that the main chain was formed by (1 → 2) β-linked D-mannose units, of which each second, on average, was substituted by monomeric D-galactose units at C(6).