• Title/Summary/Keyword: Biological Engineering

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Modeling of Typical Microbial Cell Growth in Batch Culture

  • Jianqiang Lin;Lee, Sang-Mok;Lee, Ho-Joon;Koo, Yoon-Mo
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.5 no.5
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    • pp.382-385
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    • 2000
  • A mathematical model was developed, based on the time dependent changes of the specific growth rate, for prediction of the typical microbial cell growth in batch cultures. This model could predict both the lag growth phase and the stationary growth phase of batch cultures, and it was tested with the batch growth of Trichoderma reesei and Lactobacillus delbrueckii.

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Effects of Silkworm Hemolymph on Cell Viability and hCTLA4Ig Production in Transgenic Rice Cell Suspension Cultures

  • Cheon, Su-Hwan;Lee, Kyoung-Hoon;Kwon, Jun-Young;Ryu, Hyun-Nam;Yu, Da-Hyun;Choi, Yong-Soo;Kim, Dong-Il
    • Journal of Microbiology and Biotechnology
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    • v.17 no.12
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    • pp.1944-1948
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    • 2007
  • Silkworm hemolymph (SH), prepared from fifth-instar larvae of Bombyx mori and heat-treated at $60^{\circ}C$ for 30 min, was used to improve cell viability and the production of human cytotoxic T-lymphocyte antigen 4-immunoglobulin (hCTLA4Ig) in transgenic Oryza sativa L. cell suspension cultures. Even though SH could not elevate cell viability at the concentrations up to 3% (v/v), addition of 0.3% (v/v) SH to a culture medium enhanced the production of hCTLA4Ig by 36.8% over an SH-free medium. Moreover, the production period of hCTLA4Ig could be shortened in a 0.3% (v/v) SH-added medium compared with that in an SH-free culture. As a result, addition of 0.3% (v/v) SH improved the productivity of hCTLA4Ig significantly in transgenic rice cell cultures.

Lithium Bis(oxalate)borate as an Electrolyte Salt for Supercapacitors in Elevated Temperature Applications

  • Madzvamuse, Alfred;Hamenu, Louis;Mohammed, Latifatu;Bon, Chris Yeajoon;Kim, Sang Jun;Park, Jeong Ho;Ko, Jang Myoun
    • Journal of Electrochemical Science and Technology
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    • v.8 no.4
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    • pp.314-322
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    • 2017
  • The electrolyte plays one of the most significant roles in the performance of electrochemical supercapacitors. Most liquid organic electrolytes used commercially have temperature and potential range constraints, which limit the possible energy and power output of the supercapacitor. The effect of elevated temperature on a lithium bis(oxalate)borate(LiBOB) salt-based electrolyte was evaluated in a symmetric supercapacitor assembled with activated carbon electrodes and different electrolyte blends of acetonitrile(ACN) and propylene carbonate(PC). The electrochemical properties were investigated using linear sweep voltammetry, cyclic voltammetry, galvanostatic charge-discharge cycles, and electrochemical impedance spectroscopy. In particular, it was shown that LiBOB is stable at an operational temperature of $80^{\circ}C$, and that, blending the solvents helps to improve the overall performance of the supercapacitor. The cells retained about 81% of the initial specific capacitance after 1000 galvanic cycles in the potential range of 0-2.5 V. Thus, LiBOB/ACN:PC electrolytes exhibit a promising role in supercapacitor applications under elevated temperature conditions.

Molecular Modeling, Synthesis, and Screening of New Bacterial Quorum-sensing Antagonists

  • Kim, Cheol-Jin;Kim, Jae-Eun;Park, Hyung-Yeon;Mclean, Robert J.C.;Kim, Chan-Kyung;Jeon, Jong-Ho;Yi, Song-Se;Kim, Young-Gyu;Lee, Yoon-Sik;Yoon, Je-Yong
    • Journal of Microbiology and Biotechnology
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    • v.17 no.10
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    • pp.1598-1606
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    • 2007
  • A new series comprising 7 analogs of N-(sulfanyl ethanoyl)-L-HSL derivatives, 2 analogs of N-(fluoroalkanoyl)-$_L$-HSL derivatives, N-(fluorosulfonyl)-L-HSL, and 2,2-dimethyl butanoyl HSL were synthesized using a solid-phase organic synthesis method. Each of the 11 synthesized compounds was analyzed using NMR and mass spectroscopies, and molecular modeling studies of the 11 ligands were performed using SYBYL packages. Thereafter, a bacterial test was designed to identify their quorum-sensing inhibition activity and antifouling efficacy. Most of the synthesized compounds were found to be effective as quorum-sensing antagonists, where antagonist screening revealed that 10 among the 11 synthesized ligands were able to antagonize the quorum sensing of A. tumefaciens.

Seed-Conjugated Polymer Bead for ${\beta}2$-Microglobulin Removal at Neutral pH

  • Kim, Mi-Ra;Kang, Sung-Soo;Myung, Eun-Kyung;Ahn, Min-Koo;Choi, Jeong-Hyun;Paik, Seung-R.;Lee, Yoon-Sik
    • Journal of Microbiology and Biotechnology
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    • v.19 no.9
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    • pp.960-965
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    • 2009
  • ${\beta}2$-Microglobulin (${\beta}2m$) is known to be a major factor for dialysis-related amyloidosis. We have studied ${\beta}2m$ removal through an aggregation process, which was initiated by a ligand that could catch the ${\beta}2m$ monomer and promote its aggregation into fibril. As a ligand, we have prepared ${\beta}2m$ fibril fragments and used them as a seed. The seed was coupled to PEGylated-PS beads to remove the monomeric ${\beta}2m$ from solution. The ${\beta}2m$ seed-conjugated resin effectively adsorbed the ${\beta}2m$ monomers with a capacity of 3.6 mg/ml via promoting their aggregation into fibrils on the resin at pH 7.4.

Encapsulation of CdSe/ZnS Quantum Dots in Poly(ethylene glycol)-Poly(D,L-lactide) Micelle for Biomedical Imaging and Detection

  • Lee, Yong-Kyu;Hong, Suk-Min;Kim, Jin-Su;Im, Jeong-Hyuk;Min, Hyun-Su;Subramanyam, Elango;Huh, Kang-Moo;Park, Sung-Woo
    • Macromolecular Research
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    • v.15 no.4
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    • pp.330-336
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    • 2007
  • Luminescent CdSe/ZnS QDs, with emission in the red region of the spectrum, were synthesized and encapsulated in poly(ethylene glycol)-poly(D,L-lactide) diblock copolymer micelles, to prepare water-soluble, bio-compatible QD micelles. PEG-PLA diblock copolymers were synthesized by ring opening polymerization of D,L-lactide, in the presence of methoxy PEG as a macro initiator. QDs were encapsulated with PEG-PLA polymers using a solid dispersion method in chloroform. The resultant polymer micelles, with encapsulated QDs, were characterized using various analytical techniques, such as UV- Vis measurement, light scattering, fluorescence spectroscopy, transmission electron microscopy (TEM) and atomic forced microscopy (AFM). The polymer micelles, with encapsulated QDs, were spherical and showed diameters in the range of 20-150 nm. The encapsulated QDs were highly luminescent, and have high potential for applications in biomedical imaging and detection.