Time filter

Source Type

Cai Y.,Jiangnan University | Wu H.,Jiangnan University | Liao X.,Jiangnan University | Ding Y.,Jiangnan University | And 2 more authors.
Biotechnology and Bioprocess Engineering | Year: 2010

A novel manganese peroxidase of Rhizoctonia sp. SYBC-M3 (R-MnP) was purified by (NH4)2SO4 fractionation, DEAE-cellulose-32 column chromatography, and Sephadex G100 column chromatography. The molecular mass of R-MnP was determined to be approximately 40.4 kDa by SDS-PAGE. The optimum temperature and pH for R-MnP were 55°C and 4.5, respectively. R-MnP was highly stability when the temperature was below 50°C. R-MnP could retain about 60% of its activity when the pH was between 4 and 6.5. However, R-MnP activity was inhibited by Fe3+, Cu 2+, and Co3+ as well as increased by Zn2+ and Ca2+. R-MnP demonstrated oxidation of DMP, ABTS, veratryl alcohol, and guaiacol. The Km values of RMnP for H2O2 and Mn2+ were 25.3 and 53.9 μmol/L, respectively. © 2010 The Korean Society for Biotechnology and Bioengineering and Springer-Verlag.

Wang Z.-X.,Jiangnan University | Wang Z.-X.,Hebei University of Science and Technology | Cai Y.-J.,Jiangnan University | Liao X.-R.,Jiangnan University | And 4 more authors.
Process Biochemistry | Year: 2010

The white-rot fungus Pycnoporus sp. SYBC-L1 produced large amount of laccase in submerged fermentation. Two laccase isozymes (LacI and LacII) were purified using (NH4)2SO4 fractionation, DEAE-cellulose and Sephadex G-100 column chromatography. The molecular masses of LacI and Lac II were 55.89 and 63.07kDa, respectively by SDS-PAGE. Both the laccases showed acidic pH optima and high catalytic activities at low temperature for oxidations of 2,6-dimethoxyphenol (DMP), 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonate acid) (ABTS), syringaldazine and guaiacol. LacI and LacII were not only with high cold adaptation, but also fairly stable at high temperature. The half-lives of LacI at 50, 60 and 70°C were 69.31, 2.58 and 0.13h, respectively, whereas LacII was more stable with half-lives of 256.72, 21.00 and 2.06h respectively. The best substrates for the enzymes were both found to be ABTS, in which the Km values of LacI and LacII were 0.0166 and 0.0435mM and the catalytic efficiencies were 19640.36 and 31172.64S-1mM-1, respectively. EDTA and low concentration of Cu2+ and Mn2+ almost had non-inhibitions on their activities. LacII with syringaldehyde efficiently decolorized Remazol Brilliant Blue R. The high thermostabilities as well as cold adapted properties made Pycnoporus sp. SYBC-L1 laccases to be excellent candidates in harsh industry. © 2010 Elsevier Ltd.

Yuan B.-H.,Jiangnan University | Cai Y.-J.,Jiangnan University | Liao X.-R.,Jiangnan University | Yun L.-H.,Jiangnan University | And 2 more authors.
African Journal of Biotechnology | Year: 2010

A cold-adapted lipase producing strain of mesophilic bacterium, named SYBC LIP-Y, was isolated from the decayed seeds of Ginkgo biloba L. by screening with plates containing Victoria Blue B and with the flask-shaking fermentation. It was identified as a novel Burkholderia species. The properties of its lipase after purification by PEG1000/ potassium phosphate aqueous two-phase system were characterized. The optimal pH and temperature of the enzyme was 10.0 and 30°C, respectively. About 80% of the original activity is maintained by heating at 40°C for 60 min. The lipase could also retained 70% of the maximal activity at the temperature of 0°C and suggested that it may be belonged to the cold-adapted lipase. Thus, it was proved to have good temperature stability and might have wide applicating fields. © 2010 Academic Journals.

Xie R.,China Pharmaceutical University | Xie R.,Shanghai Key Laboratory for Pharmaceutical Metabolite Research | Xie R.,Shanghai Research Center for Drug Chinese Materia Medica Metabolism | Wen J.,China Pharmaceutical University | And 9 more authors.
Journal of Pharmaceutical and Biomedical Analysis | Year: 2010

An automated system using on-line solid-phase extraction and HPLC with UV detection was developed for the determination of faropenem in human plasma and urine. Analytical process was performed isocratically with two reversed-phase columns connected by a switching valve. After simple pretreatment for plasma and urine with acetonitrile, a volume of 100 μl upper layer of the plasma or urine samples was injected for on-line SPE column switching HPLC-UV analysis. The analytes were retained on the self-made trap column (Lichrospher C18, 4.6 mm × 37 mm, 25 μm) with the loading solvent (20 mM NaH2PO4 adjusted pH 3.5) at flow rate of 2 ml min-1, and most matrix materials were removed from the column to waste. After 0.5 min washing, the valve was switched to another position so that the target analytes could be eluted from trap column to analytical column in the back-flush mode by the mobile phase (acetonitrile-20 mM NaH2PO4 adjusted pH 3.5, 16:84, v/v) at flow rate of 1.5 ml min-1, and then separated on the analytical column (Ultimate™ XB-C18, 4.6 mm × 50 mm, 5 μm).The complete cycle of the on-line SPE preconcentration purification and HPLC separation of the analytes was 5 min. Calibration curves with good linearities (r = 0.9994 for plasma sample and r = 0.9988 for urine sample) were obtained in the range 0.02-5 μg ml-1 in plasma and 0.05-10 μg ml-1 in urine for faropenem. The optimized method showed good performance in terms of specificity, linearity, detection and quantification limits, precision and accuracy. The method was successfully utilized to quantify faropenem in human plasma and urine to support the clinical pharmacokinetic studies. © 2009 Elsevier B.V. All rights reserved.

Cai Y.,Jiangnan University | Liao X.,Jiangnan University | Liang X.,Jiangnan University | Ding Y.,Jiangnan University | And 2 more authors.
New Biotechnology | Year: 2011

Hypocrellins are important photodynamic therapy compounds for cancer disease. The effect of surfactants on hypocrellin production of Shiraia sp. SUPER-H168 was evaluated under submerged fermentation condition. The production of hypocrellins could reach 780.6. mg/l with the addition of Triton X-100, confirmed by color reaction, high performance liquid chromatography, electrospray ionization mass spectrometry and nuclear magnetic resonance experiments. According to our observation, treatment of the culture at the beginning of the fermentation was most effective, and the yield of hypocrellins was much lower with the addition of Triton X-100 during the log phase and stationary phase. Shiraia sp. SUPER-H168 could not produce hypocrellin with the addition of other tested surfactants, such as Tween 40, Triton X-114 and SDS. The experimental results indicated that Shiraia sp. SUPER-H168 could not produce hypocrellins without Triton X-100 under submerged fermentation condition. © 2011 Elsevier B.V.

Discover hidden collaborations