Chunping Xu

Fermentation optimization, characterization and bioactivity of exopolysaccharides from Funalia trogii

Optimization of culture conditions for exopolysaccharide (EPS) by Funalia trogii in submerged culture was investigated using one-factor-at-a-time method and uniform design (UD). Under the optimized conditions, the maximum concentration of EPS was 8.68 g/l. After EPS was deproteinized by Sevag method, two groups of EPSs (designated as Fr-I and Fr-II) were obtained from the culture filtrates by gel filtration chromatography on Sepharose CL-6B. Furthermore, EPSs were characterized by size exclusion chromatography (SEC) coupled with a multiangle laser-light scattering (MALLS) and refractive index (RI) detector system. The weight-average molar masses of the Fr-I and Fr-II were determined to be 1.007 × 10(5) and 2.393 × 10(4)g/mol, respectively. The root mean square (RMS) radii for both peaks ranged from 9.7 to 10.8 nm with no clear trends. Pharmacology experiments indicated F. trogii EPS were useful to the therapy of free radical injury and cancer diseases.

Production, fractionation, characterization of extracellular polysaccharide from a newly isolated Trametes gibbosa and its hypoglycemic activity.

The submerged fermentation for extracellular polysaccharide (EPS) production from Trametes gibbosa was optimized. An optimal medium for EPS production was obtained through central composite design (CCD) as follows: 53.12 g/L maltose and 4.21 g/L polypeptone in distilled water. Furthermore, four groups of EPSs (designated as Fr-I, Fr-II, Fr-III and Fr-IV) were obtained from the culture filtrates by size exclusion chromatography (SEC), and their molecular characteristics were examined by a multiangle laser-light scattering (MALLS) and refractive index (RI) detector system. The weight-average molar mass of Fr-I was determined to be 3.872 x 10(5)g/mol and its molecular shape was revealed to be a rigid rod in an aqueous solution. Finally, the hypoglycemic effect of the EPS, investigated in streptozotocin induced diabetic mice, decreased plasma glucose, total cholesterol and triacylglycerol concentrations by 17.4%, 14.0% and 12.6%, respectively. The results indicate the potential of this EPS to prevent hyperglycemia in diabetic patients.

PRODUCTION, PRELIMINARY CHARACTERIZATION, AND BIOACTIVITIES OF EXOPOLYSACCHARIDES FROM Pleurotus geesteranus 5 #

The optimal culture conditions of exopolysaccharides (EPS) production in submerged culture medium by Pleurotus geesteranus 5 # were determined using an orthogonal matrix method. The optimal defined medium (per liter) was 60.0 g maltose, 5.0 g tryptone, 1 mM NaCl, 5 mM KH2PO4, and initial pH 6.0 at 28 °C. In the optimal culture medium, the maximum EPS production was 16.97 g/L in a shake flask. Two groups of EPSs (designated as Fr-I and Fr-II) were obtained from the culture filtrates by size exclusion chromatography (SEC), and their molecular characteristics were examined by a multiangle laser-light scattering (MALLS) and refractive index (RI) detector system. The approximate weight-average molar masses of the Fr-I and Fr-II of EPS were determined to be 3.263 × 104 and 5.738 × 103 g/mol, respectively. The low values of polydispersity ratio (1.176 and 1.124 for Fr-I and Fr-II, respectively) of EPSs mean that these EPS molecules exist much less dispersed in aqueous solution without forming large aggregates. Furthermore, the experiments in vitro indicated that P. geesteranus 5# EPS exhibit high antitumor and antioxidative effects.

Preparation and bioactivity of exopolysaccharide from an endophytic fungus Chaetomium sp. of the medicinal plant gynostemma pentaphylla

Background: Many exopolysaccharides from the endophytes in medicinal plants possess various potential bioactivities. Materials and Methods: The endophytic fungus JY25 was isolated from the leave of the Chinese medicinal plant Gynostemma pentaphylla and identified as Chaetomium sp. by its phylogenetic and physiological analysis. One exopolysaccharide (EPS) fraction was isolated from the fermentation broth by ethanol precipitation and purified by gel filtration chromatography on Sepharose CL-6B. The molecular characteristics were examined by GC-MS, FT-IR, and multiangle laser light scattering (MALLS). Results: The monosaccharide composition analysis indicated that the purified EPS was mainly composed of glucose, mannose, arabinose, and galactose with the molecular ratio of 78.29: 8.99: 8.64: 4.08. FT-IR spectral analysis of the purified EPS revealed prominent characteristic groups, such as carbonyl bond, pyranose ring, and so on. The weight-average molar mass and the polydispersity ratio of the EPS were revealed to be 1.961×104 g/mol and 1.838, respectively. Furthermore, thermo gravimetric analysis (TGA) indicated that the degradation temperature of the purified EPS was 305°C. The purified EPS from the endophytic fungus Chaetomium sp. displayed antioxidant and antiproliferative activities. Conclusion: The results demonstrated that the EPS could be used as a healthful food and material source in pharmaceutical industries. Abbreviations used: ANOVA: Analysis of variance; DPPH: 2,2-diphenyl-1-picrylhydrazyl; EPS: Exopolysaccharide; FT-IR: Fourier transform infrared spectroscopy; GC-MS: Gas chromatography–mass spectrometry; Mw: Mass weight; MALLS: Multiangle laser light scattering; SEC: Size Exclusion Chomatography; SPSS: Statistical Package of the Social Science; TGA: Thermo gravimetric analysis; TFA: Trifluoroacetic acid.

Characterization and Antiproliferative Effect of Novel Acid Polysaccharides from the Spent Substrate of Shiitake Culinary-Medicinal Mushroom Lentinus edodes (Agaricomycetes) Cultivation

In this study, a high yield of crude polysaccharide (16.73 ± 0.756%) was extracted from the spent mushroom substrate of Lentinus edodes using a hot alkali extraction method. Two groups of polysaccharides (designated as LSMS-1 and LSMS-2) were obtained from the crude extract by size exclusion chromatography (SEC), and their molecular characteristics were examined by a multiangle laser-light scattering (MALLS) and refractive index detector system. The weight-average molar masses of LSMS-1 and LSMS-2 were determined to be 6.842 × 106 and 2.154 × 106 g/mol, respectively. The SEC/MALLS analysis revealed that the molecular shapes of LSMS-1 and LSMS-2 were sphere-like forms in aqueous solution. Carbohydrate composition analysis using chromatography--mass spectrometry revealed that they were both acid heteropolysaccharides. LSMS-1 comprised mainly glucose and galacturonic acid, whereas LSMS-2 mainly consisted of xylose and glucuronic acid. Fourier transform infrared spectral analysis of the purified fractions revealed typical characteristic polysaccharide groups. In addition, MTT assays with refined polysaccharide doses of 25, 50, 100, 200, and 400 µg/mL suggested that both of the polysaccharide fractions exhibited antiproliferative activity against 6 tested human tumor cell lines in a concentration-dependent manner, and LSMS-2 had better anticancer capacity in vitro than LSMS-1. The inhibition ratio of LSMS-2 against A549 human lung cancer cells, the SGC7901 gastric cancer cell line, MCF-7 breast cancer cells, the U937 histiocytic lymphoma cell line, and the MG-63 human osteosarcoma cell line reached 43.55%, 29.97%, 19.63%, 18.24%, and 17.93%, respectively, at a concentration of 400 µg/mL.

Sulfation of the Extracellular Polysaccharide Produced by the King Oyster Culinary-Medicinal Mushroom, Pleurotus eryngii (Agaricomycetes), and Its Antioxidant Properties In Vitro

Extracellular polysaccharide from Pleurotus eryngii was sulfated; the optimum reaction conditions used pyridine as the reaction solvent, a temperature of 80°C, and a reaction time of 90 minutes. The structure and antioxidant activity of the sulfated and original polysaccharides (designated as SF-1 and Fr-1, respectively) were investigated. The main functional groups of polysaccharides were determined by Fourier transform infrared, and the chain conformation was determined by size-exclusion chromatography with laser light scattering and viscometry. Fourier transform infrared spectra indicated that the sulfated group was linked to the polymer. The molecular weight of SF-1 was much lighter than that of Fr-1, which suggested that degradation occurred during sulfation. The stable globular shape conformation of Fr-1 was changed to the random coil conformation of SF-1 in the aqueous solution. Moreover, the sulfated derivative SF-1 was found to have a better scavenging ability on hydroxyl radicals and DPPH free radicals than Fr-1. It seems that the chemical modification of P. eryngii polysaccharides by sulfation effectively enhances their antioxidant activity.

Quality Comparison of Hawthorn Wines Fermented by Saccharomyces cerevisiae with and without Pulp Contact and Pectase Treatment

This study evaluated the chemical and volatile composition of hawthorn wines fermented with Saccharomyces cerevisiae A3.12 with and without pulp contact and pectase treatment during fermentation. The results indicated that the addition of pectase was in favor of pH decrease and clarification. The pectase-treated wines had significantly higher concentrations of acetic acid, ethyl octanoate, and isoamyl acetate than the non-enzyme-treated wines. Furthermore, the nonextracted wines had significantly higher concentrations of isoamyl alcohol, phenylethyl alcohol, ethyl lactate, and isoamyl acetate than the extracted wines. The first principal component separated the wine from the nonextracted juice with pectase from other samples based on the higher concentrations of isoamyl acetate (0.14 μg/g), diethyl butanedioate (0.07 μg/g), 2-phenylethyl acetate (0.23 μg/g), and acetoin (1.47 μg/g). The wine from nonextracted pulpy juice with pectase was significantly more aromatic than the others and 26.2% of the consumers were found to be willing to purchase this product.

Effect of carbon source on production, characterization and bioactivity of exopolysaccharide produced by Phellinus vaninii Ljup

The effect on different three carbon source (i.e. glucose, fructose and sucrose) on production, chemical characterization and antioxidant activity of exopolysaccharide (EPS) produced by Phellinus vaninii Ljup was investigated in this study. Amongst carbon sources examined, glucose and sucrose were favorable for the mycelia growth, while the maximum EPS yield was achieved when sucrose was employed. The predominant carbohydrate compositions in EPSs identified were gluconic acid, glucose, mannose and galactose acid. Then, FT-IR spectral analysis revealed prominent characteristic groups in EPSs. EPSs molecule exist as nearly globular shape form in aqueous solution. The variation also affects antioxidant activities by investigated by using hydroxyl and DPPH radical scavenging assay. Sucrose was best carbon source from the viewpoint of antioxidant activity due to the relatively high contents of galactose in the EPS with moderate molecular weight and polydispersity.

Simultaneous Determination of Furan and Vinyl Acetate in Vapor Phase of Mainstream Cigarette Smoke by GC-MS

A simple and sensitive method for simultaneous determination of furan and vinyl acetate (VA) in vapor phase of mainstream cigarette smoke with cold trap and gas chromatography-mass spectrometry (GC-MS) was developed. A Cambridge filter pad (CFP) was placed in front of the impingers of smoking machine to remove the particle phase from cigarette smoke. Furan and VA in vapor phase of mainstream cigarette smoke were collected in two impingers connected in series by filled with methanol at -78°C. The solutions were added with deuterium-labeled furan-d4 and VA-d6 as internal standards and analyzed by GC-MS. The results showed that the calibration curves for furan and VA were linear (r2 > 0.9995) over the studied concentration range. The intra- and inter-day precision values for furan and VA were <7.07% and <9.62%, respectively. The extraction recoveries of furan and VA were in the range of 94.5-97.7% and 92.3-94.9%, respectively. Moreover, the limits of detection for furan and VA were 0.028 µg mL-1 and 1.3 ng mL-1, respectively. The validated method has been successfully applied to determine the emissions of furan and VA in the vapor phase of mainstream cigarette smoke under International Organization for Standardization (ISO) and Canadian Intense (CI) smoking regimen.

Production, Purification and Physicochemical Properties of an Exo-Polygalacturonase from Aspergillus niger SW06

In this study, exo-polygalacturonase (exo-PG) production from Aspergillus niger SW06 was optimized by central composition design and high amount of 21.51 units mL could be achieved in optimizing growth conditions. Both gel filtration and ion exchange chromatography revealed a single exo-PG activity peak, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the purified protein showed a single band with a molecular mass of 66.2 kDa. The purified enzyme exhibited maximal activity in the presence of 1% citrus pectin at the temperature of 55 °C and pH of 5.0. The enzyme was stable within the pH range of 3.0-5.0 and below 60 °C. The Michaelis constant (Km) and maximum velocity (Vmax) of the enzyme was found to be 0.58 mg mL and 20.66 μmol (mL min), respectively. The thermostable and acidic nature for the activity of this exo-PG make it possible to have wide range of industrial applications.