• Title/Summary/Keyword: biochemical characterization

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Conducting and interface characterization of carbonate-type organic electrolytes containing EMImBF4 as an additive against activated carbon electrode

  • Kim, Mingyeong;Kim, Kyungmin;Kim, Seok
    • Carbon letters
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    • v.16 no.1
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    • pp.51-56
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    • 2015
  • Carbonate-type organic electrolytes were prepared using propylene carbonate (PC) and dimethyl carbonate (DMC) as a solvent, quaternary ammonium salts, and by adding different contents of 1-ethyl-3-methyl imidazolium tetrafluoroborate ($EMImBF_4$). Cyclic voltammetry and linear sweep voltammetry were performed to analyze conducting behaviors. The surface characterizations were analyzed by scanning electron microscopy method and X-ray photoelectron spectroscopy. From the experimental results, increasing the $EMImBF_4$ content increased the ionic conductivity and reduced bulk resistance and interfacial resistance. In particular, after adding 15 vol% $EMImBF_4$ in 0.2 M $SBPBF_4$ PC/DMC electrolyte, the organic electrolyte showed superior capacitance and interfacial resistance. However, when $EMImBF_4$ content exceeded 15 vol%, the capacitance was saturated and the voltage range decreased.

Cloning, Characterization of Pichia etchellsii $\beta-Glucosidase$ II and Effect of Media Composition and Feeding Strategy on its Production in a Bioreactor

  • Sethi Benu;Jain Monika;Chowdhary Manish;Soni Yogesh;Bhatia Yukti;Sahai Vikram;Mishra Saroj
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.7 no.1
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    • pp.43-51
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    • 2002
  • The cloning and expression of $\beta-glucosidase$ II, encoded by the gene ${\beta}glu2$, from thermotolerant yeast Pichia etchellsii into Escherichia coli is described. Cloning of the 7.3 kb BamHI/SalI yeast insert containing ${\beta}glu2$ in pUC18, which allowed for reverse orientation of the insert, resulted in better enzyme expression. Transformation of this plasmid into E. coli JM109 resulted in accumulation of the enzyme in periplasmic space. At $50^{\circ}C$, the highest hydrolytic activity of 1686 IU/g protein was obtained on sophorose. Batch and fed-batch techniques were employed for enzyme production in a 14 L bioreactor. Exponential feeding rates were determined from mass balance equations and these were employed to control specific growth rate and in turn maximize cell growth and enzyme production. Media optimization coupled with this strategy resulted in increased enzyme units of 1.2 kU/L at a stabilized growth rate of $0.14\;h^{-l}$. Increased enzyme production in bioreactor was accompanied by formation of inclusion bodies.

Characterization of bacillus thuringiensis isolate HL-15 from Korean soil (토양에서 분리한 bacillus thuringiensis의 특성)

  • 이형환;박미연;이창운
    • Korean Journal of Microbiology
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    • v.24 no.2
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    • pp.175-183
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    • 1986
  • The isolate HL-15 of Bacillus thuringiensis had common biochemical characteristics of the 23 serovarieties of B. thuringiensis. The isolates formed round endotoxin crystals which killed insect larvae, showed independent serological H antigen to the 23 serotypes, and contained two defferect DNA elements with over 100 Mdaltons of molecular weights.

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