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Liu Y.,Tianjin University of Science and Technology | Zhao L.,East China University of Science and Technology | Zhang J.,University of Shanghai for Science and Technology | Zheng Y.,Key Laboratory of Industrial Fermentation Microbiology
Lecture Notes in Electrical Engineering | Year: 2015

Glycerol dehydrogenase (GDH) was a key enzyme for 1,3-propanediol fermentation from glycerol. In this report, gene gdh, encoding GDH of Klebsiella pneumoniae KG1 was gained by PCR with genomic DNA as template. The open reading frame (ORF) of gdh consisted of 1,143 bp and encoded 380 amino acids with a deduced molecular mass of 42 kDa. The gene gdh was overexpressed in E. coli BL21 (DE3) and produced 886-fold higher activity of GDH than that of KG1. The optimum temperature of recombinant GDH was 37 °C and glycerol was the optimum substrate. © Springer-Verlag Berlin Heidelberg 2015. Source


Jia Y.,Key Laboratory of Industrial Fermentation Microbiology | Jia Y.,Tianjin University of Science and Technology | Huo M.,Key Laboratory of Industrial Fermentation Microbiology | Huo M.,Tianjin University of Science and Technology | Jia S.,Tianjin University of Science and Technology
Lecture Notes in Electrical Engineering | Year: 2014

The preparation and characterization of bacterial cellulose (BC)/hyal-uronic acid (HA) nanocomposites are presented in this paper. BC/HA composites have been prepared by solution immersion method, biosynthesis method, and crosslink method. HA concentration (1, 10, and 12.5 g/L) was used as a variable factor. These materials were characterized by Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared (FTIR) spectroscopy, and X-ray Diffraction (XRD). And tensile strength and young's modulus were tested for composites from solution immersion and biosynthesis. SEM graphs of the composites show that HA penetrated inside the cellulose network, filling the space of the network, and keeping a close interaction with the nanofibrils. FTIR spectra illustrate the integration of HA in the composites derived by solution immersion and crosslink method. The crystallinity index of all three composites was reduced slightly compared with pristine BC, known from XRD spectra. For composites from solution immersion and biosynthesis, the young's modulus and tensile strength of BC/HA have been improved compared with the pure BC. This is due to the enhanced hydrogen bonds offered by the interaction between HA and BC. In summary, all the three methods can provide composites of BC and HA. Further, biocompatibility tests will be carried out to evaluate these materials in terms of the potential applications on the biomedical field. © Springer-Verlag Berlin Heidelberg 2014. Source


Liu Y.,Key Laboratory of Industrial Fermentation Microbiology | Liu Y.,National Engineering Laboratory for Industrial Enzymes | Liu Y.,Tianjin Key Laboratory of Industrial Microbiology | Liu Y.,Tianjin University of Science and Technology | And 13 more authors.
Biotechnology Letters | Year: 2012

The gene encoding a novel alkaline pectate lyase (Apel) from Bacillus subtilis was cloned and expressed in B. subtilis WB600. Apel contained an ORF of 1,260 bp, encoding a signal peptide of 21 amino acids and a mature protein of 399 amino acids with a calculated molecular mass of 45497.9 Da. The mature Apel was structurally related to the enzymes in the polysaccharide lyase family 1. After purification, the recombinant Apel had a specific activity of 445 U mg -1. The enzyme was optimally active at 50°C and pH 9. © 2011 Springer Science+Business Media B.V. Source


Zhong C.,Key Laboratory of Industrial Fermentation Microbiology | Zhong C.,Tianjin University of Science and Technology | Wang R.,Key Laboratory of Industrial Fermentation Microbiology | Wang R.,Tianjin University of Science and Technology | And 9 more authors.
Journal of Agricultural and Food Chemistry | Year: 2012

Seeking cheap, sustainable protein sources greatly facilitates in alleviating the dependence upon expensive animal-based protein in many developing countries. Caragana korshinskii Kom. offers a good alternative feedstock because of its high-content of protein, low fertilizer and pesticide requirements, excellent stress (high salty and less water) tolerance, wide adaptability, etc. The functional properties of C. korshinskii Kom. protein isolates by three different extraction methods were investigated. The extraction processes greatly influenced the physiological characteristics of protein isolates. C. korshinskii Kom. protein isolate by traditional alkaline extraction (Al-CPI) exhibited good performance on emulsifying activity index, oil and water absorption capacity, and foaming property compared to A-CPI (C. korshinskii Kom. protein isolate by the acetone precipitation method) and TCA-CPI (C. korshinskii Kom. protein isolate by trichloroacetic acid-acetone precipitation). The water and oil adsorption capacities of Al-CPI were observed at 4.99 and 3.45 g/g, respectively, even much higher than those of soy protein isolate (SPI) (3.94 and 2.95 g/g, respectively). The highest foaming capacity was observed by Al-CPI at 185.0%, followed by A-CPI (177.5%), TCA-CPI (142.5%), and SPI (141.9%), respectively. It has to be noted that A-CPI showed good solubility at acidic pH and excellent in vitro digestibility. After sequential pepsin-trypsin digestion, the percentage of N release of A-CPI reached up to 83.7%, which was 1.63 times that of Al-CPI (51.2%), 1.19 times that of TCA-CPI (70.1%), and slightly higher than that of the commercial SPI (82.5%). These results indicate that C. korshinskii Kom. holds great potential for application in the animal feed and food additive industry. © 2012 American Chemical Society. Source


Sun M.-Z.,Key Laboratory of Industrial Fermentation Microbiology | Zheng H.-C.,CAS Tianjin Institute of Industrial Biotechnology | Meng L.-C.,China Agricultural University | Sun J.-S.,Chinese Academy of Agricultural Sciences | And 8 more authors.
Biotechnology Letters | Year: 2015

Objectives: To acquire a thermostable xylanase, that is suitable for xylooligosaccharide production from pretreated corncobs, the metagenomic method was used to obtain the gene from an uncultured environmental microorganism. Results: A thermostable xylanase-encoding gene (xyn10CD18) was cloned directly from the metagenomic DNA of cow dung compost. When xyn10CD18 was expressed in Bacillus megaterium MS941, extracellular xylansae activity at 106 IU/ml was achieved. The purified recombinant Xyn10CD18 was optimally active at pH 7 and 75 °C as measured over 10 min. It retained over 55 % of its initial activity at 70 °C and pH 7 after 24 h. Its action on birchwood xylan for 18 h liberated xylooligosaccharides with 2°–4° of polymerization, with xylobiose and xylotetraose as the main products. When pretreated corncobs were hydrolyzed by Xyn10CD18 for 18 h, the xylooligosaccharides (DP 2–4) products increased to 80 % and the xylose was just increased by 3 %. Conclusion: Xyn10CD18 is a thermostable endoxylanase and is a promising candidate for biomass conversion and xylooligosaccharide production. © 2015, Springer Science+Business Media Dordrecht. Source

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