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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Korean Society for Biotechnology and Bioengineering
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Volume & Issues
Volume 21, Issue 6 - Dec 2006
Volume 21, Issue 5 - Oct 2006
Volume 21, Issue 4 - Aug 2006
Volume 21, Issue 3 - Jun 2006
Volume 21, Issue 2 - Apr 2006
Volume 21, Issue 1 - Feb 2006
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Enhancement of L-lysine Productivity by Strain Improvement and Optimization of Fermentation Conditions in Corynebacterium glutamicum
Seo, Jin-Mi ; Hyun, Hyung-Hwan ;
KSBB Journal, volume 21, issue 2, 2006, Pages 79~84
In order to minimize the reduction of lysine productivity by accumulation of lysine and byproducts in the end of fed-batch fermentations, a salt-tolerant mutant C14-49-3-15-7-3-20, which could grow at high concentrations of NaCl was isolated through mutagenesis from the Corynebacterium glutamicum mother strain I. In the evaluation of L-lysine productivity by fed-batch fermentations using a 5 L jar fermenter, the salt-tolerant mutant strain C14-49-3-15-7-3-20 produced 130.6 g/L of L-lysine with a 48.6% of yield. The mother strain I produced L-lysine concentration only 104.9 g/L with a yield 41.8%, implying the improvement of L-lysine productivity by introduction of salt-tolerance character.
and Ferulic Acid on Laccase and Manganese Peroxidase Production by Funalia trogii
Park, Chul-Hwan ; Han, Eun-Jung ; Lee, Byung-Hwan ; Lee, Jin-Won ; Kim, Sang-Yong ;
KSBB Journal, volume 21, issue 2, 2006, Pages 85~89
Typical property of the white-rot fungi is their ability to degrade lignin and other aromatic compounds with non-specific extracellular enzyme. In this work, the modification of the strain(Funalia trogii ATCC 200800) and the culture condition was performed to enhance enzyme productivity. Single cell was separated by the protoplasts formation and several putative laccase and manganese peroxidase inducers were tested. By adopting the modified strain, enzyme productivity increased comparing with that of the original strain. Extracellular enzyme formation was highly stimulated by the addition of copper and various aromatic compounds in the glucose-based culture medium.
Enhanced Lycopene Production in Recombinant Escherichia coli by Random Transposon and NTG Mutagenesis
Yoon, Sang-Hwal ; Ko, Min-Su ; Park, Kyoung-Ae ; Jung, Kyung-Hwa ; Shin, Yong-Chul ; Lee, Young-Mi ; Lee, Sook-Hee ; Kim, Seon-Won ;
KSBB Journal, volume 21, issue 2, 2006, Pages 90~95
Escherichia coli harboring pAC-LYCO4 and pDdxs was used for lycopene production. Three wild type strains of E. coli OW1, MG1655, and W3110 were compared with DH5
used before for lycopene production. Lycopene productivity of E. coli MG1655 was similar to DH5
and the highest among those wild type strain. Therefore, MG1655 strain was used for random transposon and NTG mutagenesis to increase lycopene productivity. Through transposon mutation, five transposon mutants with increased lycopene productivity were obtained. It was found that genes knocked out by transposon insertion were treB in Tn1 mutant, B2436 in Tn2 mutant, and rfaH in Tn3, 4, and 5 mutants. Lycopene productivity was the highest in Tn4 mutant among the Tn mutants, which was 6-fold and 8-fold higher in lycopene concentration and content, respectively, in comparison with those obtained with wild type strain. NTG4 mutant was acquired with NTG mutation. The highest lycopene productivity of 6 mg/L and 4 mg/g DCW was obtained from the NTG4 mutant when arabinose of 0.013 mM was added for induction of dxs, rate-limiting gene of MEP pathway. The lycopene productivity of NTG4 mutant was increased 18-fold and 12-fold in lycopene concentration and content, respectively when comparing with the wild type strain.
Optimization of Submerged Cultivation of Hericium erinaceum
Jung, Jae-Hyun ; Lee, Keun-Eok ; Lee, Shin-Young ;
KSBB Journal, volume 21, issue 2, 2006, Pages 96~102
Recently, it has been known that Hericium erinaceum is a one of the very useful functional materials with great attention in mushroom processing industry. In present study, a liquid culture which was not studied systematically until now, was conducted as a method of cultivation for H. erinaceum, and also examined the characteristics of the liquid culture and conditions of process optimization. A good basal medium was selected through the cultivation of 16 species mushroom media and the optimum condition for medium and cultivation were chosen by response surface method. From these results, the optimum condition of medium for mushroom was 3% glucose, 0.2% yeast extract/peptone(1:1) and 0.1%
(1:1) and also the optimal culture condition was obtained at inoculum of 13.42%, temperature of
and pH of 5.7. The mycelial dry weight of 9 g/I was obtained under these conditions and this amount was about 1.7 times higher than that which were cultivated in basal medium for 8 days.
Cultural Characteristics and Scale-up for Submerged Cultivation of Hericium erinaceum Through Air-lift and Jar Fermenter System
Jung, Jae-Hyun ; Lee, Keun-Eok ; Lee, Shin-Young ;
KSBB Journal, volume 21, issue 2, 2006, Pages 103~109
For the study of Hericium erinaceum as a useful functional foods and materials, liquid cultivation under two different bioreactors(air-lift fermenter and jar fermenter) which was not studied systematically until now, was conducted as a method of mass cultivation for H. erinaceum. A batch cultivation in an air-lift fermenter and a jar fermenter was examined for enhancing the productivity because of small amounts of mycelial weight and slow growth in case of a liquid culture for H. erinaceum. We found that air lift fermenter system was more effective than jar fermenter for mycelial production of H. erinaceum, and mycelial morphology was a critical factor of the growth. By scale-up and cultivation based on morphological analysis, the conditions for mass production with 30 L and 500 L jar fermenter was 200 and 150 rpm of agitation speed at 1 vvm of aeration rate, respectively, and mycelial dry weight under these conditions was enhanced to about
Cryopreservation of CHO Cell using Serum-Free Media
Kim, Yoo-Kang ; Park, Hong-Woo ; Choe, Tae-Boo ;
KSBB Journal, volume 21, issue 2, 2006, Pages 110~117
During routine maintenance, animal cell lines are commonly cryopreserved in growth medium containing serum with 10% DMSO. But, in case of bioprocess under the serum-free conditions, including cultivation of cell lines and producing of pharmaceuticals, the cryopreservation should be executed without serum to prevent a cross-contamination. This experiments were performed to investigate the effects of the serum-free cryopreservation on the CHO cells. To improve the survival rates of the cryopreserved CHO cells in serum-free condition, first, the effects of permeable and non-permeable additives for substitute serum on cell viability were investigated. The combination of 10% DMSO and 0.03 M raffinose in MEM-
without serum indicated 76% of cell viability. However, it did not reach the survival rates(more than 95%) of the conventional cryopreservation. In the second, to evaluate the cryopreservative ability of the serum-free medium(SFM) we compared viability of the CHO cells cryopreserved in the SFMs(Sigma C5467, C4726, and C1707, JBI SF486 and PF486), the cryoprotectant(Genenmed CAN-1000) and the MEM-
with serum. All solution contained 10% DMSO. As a result of the comparison, cryopreserved cells in the SFMs showed over 95% of viability and appeared predominant viability better than cryoprotectant CAN-1000. Finally, we assessed the stability of the CHO cells in the long-term cryopreservation(LTC) using SFM. Every three months, the cryopreserved CHO cells were thawed to estimate the cell viability and the recovery rates. Then, real-time RT-PCR analyzed the inserted CHO DHFR gene. All results for the LTC appeared the same stability as the serum containing cryopreservation. In the conclusion, it could be seen that the LTC in the SFM can substitute for serum using methods in the bioprocess proceeded by CHO cells for more than 18 months.
Enhanced Synthesis of Active rPA in the Continuous Exchange Cell-free Protein Synthesis [CECF] System utilizing Molecular Chaperones
Park, Chang-Gil ; Kim, Tae-Wan ; Choi, Cha-Yong ; Kim, Dong-Myung ;
KSBB Journal, volume 21, issue 2, 2006, Pages 118~122
In this report, we describe that the use of GroEL/GroES-enriched S30 extract remarkably enhances the solubility and enzymatic activity of cell-free synthesized rPA, which requires the correct formation of 9 disulfide bonds for its biological activity. We found that the stable maintenance of redox potential is necessary, but not sufficient for the optimal expression of active rPA. In a control reaction without using additional molecular chaperones, most of the rPA molecules were aggregated almost instantly after their expression and thus failed to exhibit the enzymatic activity. However, by the use of GroEL/GroES-enriched extract, combined with IAM-treatment, approximately
of active rPA was expressed in the cell-free synthesis reaction. This result not only demonstrates the efficient production of complex proteins, but also shows the control and flexibility offered by the cell-free protein synthesis system.
High-Yield Production of Astragalosides from Transgenic Hairy Root Cultures of Astragalus membranaceus
Hwang, Sung-Jin ;
KSBB Journal, volume 21, issue 2, 2006, Pages 123~128
A transgenic hairy root clone AG-04 of Astragalus membranaceus was obtained following co-cultivation of leaf explants with Agrobacterium rhizogenes ATCC15834. This clone was examined for its growth and production of cyclolanostane-type saponins, astragalosides I, II, and III, under various culture conditions. Among the five basal media tested, Shenk and Hildebrandt(SH)(18) medium was best for roots growth and astragalosides production. The maximum root biomass was obtained at inoculum size of 500 mg FRW per flask, initial sucrose concentration of 3%, and shaking speeds of 90 rpm. The astagalosides production was promoted when the hairy root clone AG-04 was cultured at shaking speeds of 120 rpm and light irradiation of 18 h. Astragaloside contents was also stimulated with high initial sucrose concentration, and the maximum astargalosides contents of 6.21 %/g DRW was obtained at initial sucrose concentration of 6%. The addition of chitosan(100 mg/L) to the culture medium was significantly increased astragalosides production. This was 2.1 times higher than that obtained in a control culture without chitosan.
Antimicrobial Activity of Water-soluble Extract from Artemisia princeps var. orientalis
Cho, Hwa-Young ; Yoon, Sung-Yong ; Park, Jeong-Jin ; Yun, Kung-Won ; Park, Jong-Moon ;
KSBB Journal, volume 21, issue 2, 2006, Pages 129~132
The importance of natural preservative has increased in recent years. The natural preservatives have been used in the field of foods, cosmetics and pharmacology. In the present work Artemisia sp., well recognized for their effect of antimicrobial activity, were extracted by methanol and water sequentially for selecting only water-soluble compounds that can be used as additives in food and cosmetics. Antimicrobial activities of water extracts from stem and leaf of Artemisia princeps var. orientalis were investigated by the disc diffusion method. Two gram positive bacteria(Staphylococcus aureus and Bacillus subtilis) and three gram negative bacteria(Escherichia coil, Agrobacterium tumefaciens and Pseudomonas putida) were used for antimicrobial activity studies. The water-soluble compounds from methanol extract showed higher antimicrobial activity than only water extract to these bacteria. Comparative evaluation of water-soluble metabolite profiles with caffeic acid that is known as an antimicrobial compound from Artemisia sp. was performed by high performance liquid chromatography with photo-diode array detection.
Solid-phase PEGylation for Site-Specific Modification of Recombinant Interferon
-2a : Process Performance, Characterization, and In-vitro Bioactivity
Lee, Byung-Kook ; Kwon, Jin-Sook ; Lee, E.K. ;
KSBB Journal, volume 21, issue 2, 2006, Pages 133~139
In 'solid-phase' PEGylation, the conjugation reaction occurs as the proteins are attached to a solid matrix, and thus it can have distinct advantages over the conventional, solution-phase process. We report a case study: rhIFN-
-2a was first adsorbed to cation exchange resin and then N-terminally PEGylated by aldehyde mPEG of 5, 10, and 20 kD through reductive alkylation. After the PEGylation, salt gradient elution efficiently recovered the mono-PEGylate in a purified form from the unwanted species such as unmodified IFN, unreacted PEG, and others. The mono-PEGylation and its purification were integrated in a single chromatographic step. Depending on the molecular weight of the mPEG aldehyde used, the mono-PEGylation yield ranged 50-64%. We could overcome the major problems of random, or uncontrollable, multi-PEGylation and the post-PEGylation purification difficulties associated with the solution-phase process. N-terminal sequencing and MALDI-TOF MS confirmed that a PEG molecule was conjugated only to the N-terminus. Compared with the unmodified IFN, the mono-PEGylate showed the reduced anti-viral activity as measured by the cell proliferation assay. The bioactivity was reduced more as the higher molecular weight PEG was conjugated. Immunoreactivity, evaluated indirectly by antibody binding activity using a surface plasmon resonance biosensor, also decreased. Nevertheless, trypsin resistance as well as thermal stability was considerably improved.
Characterization of Formation of Fructose during Acid Hydrolysis and Enzyme Treatment of Fructose Saccharides
Kang, Soon-Ah ; Lee, Eun-Young ; Jung, Sung-Je ; Kim, Sang-Moo ; Lee, Jae-Cheol ; Jang, Ki-Hyo ;
KSBB Journal, volume 21, issue 2, 2006, Pages 140~143
Acid- and enzymatic hydrolysis properties of two fructans(inulin and levan) and their oligofructoses has been investigated. At pH 1, the initial fructose release rate differs and is rapidly hydrolyzed in the order of levan oligosaccharide and inulin oligosaccharide, levan, inulin. At pH 4.5, 7 and 14, no or little amount of fructose are found from four samples. At the presence of inulinase in the reaction mixture, the fructose is rapidly produced from all samples, whilst invertase treatments show low activities. The results allow the estimation of the fructose release rate in many foodstuff processing conditions.
Structural Characteristics of Expression Module of Unidentified Genes from Metagenome
Park, Seung-Hye ; Jeong, Young-Su ; Kim, Won-Ho ; Kim, Geun-Joong ; Hur, Byung-Ki ;
KSBB Journal, volume 21, issue 2, 2006, Pages 144~150
The exploitation of metagenome, the access to the natural extant of enormous potential resources, is the way for elucidating the functions of organism in environmental communities, for genomic analyses of uncultured microorganism, and also for the recovery of entirely novel natural products from microbial communities. The major breakthrough in metagenomics is opened by the construction of libraries with total DNAs directly isolated from environmental samples and screening of these libraries by activity and sequence-based approaches. Screening with activity-based approach is presumed as a plausible route for finding new catabolic genes under designed conditions without any prior sequence information. The main limitation of these approaches, however, is the very low positive hits in a single round of screening because transcription, translation and appropriate folding are not always possible in E. coli, a typical surrogate host. Thus, to obtain information about these obstacles, we studied the genetic organization of individual URF's(unidentified open reading frame from metagenome sequenced and deposited in GenBank), especially on the expression factors such as codon usage, promoter region and ribosome binding site(rbs), based on DNA sequence analyses using bioinformatics tools. And then we also investigated the above-mentioned properties for 4100 ORFs(Open Reading Frames) of E. coli K-12 generally used as a host cell for the screening of noble genes from metagenome. Finally, we analyzed the differences between the properties of URFs of metagenome and ORFs of E. coli. Information derived from these comparative metagenomic analyses can provide some specific features or environmental blueprint available to screen a novel biocatalyst efficiently.
Stability of Vitamin-C Inclusion Comolexes Prepared using a Solvent Evaporation Method
Yang, Jun-Mo ; Lee, Yun-Kyung ; Kim, Eun-Mi ; Jung, In-Il ; Ryu, Jong-Hoon ; Lim, Gio-Bin ;
KSBB Journal, volume 21, issue 2, 2006, Pages 151~156
Vitamin-C is one of the typical bioactive substances widely used in the cosmetic and pharmaceutical applications. It is well known that the bioavailability of vitamin-C decreases with time because it is spontaneously oxidized in the presence of oxygen. In this study, vitamin-C inclusion complexes were prepared by formulating vitamin-C with 2-hydroxypropyl-
-CD) to protect vitamin-C from being oxidized. Vitamin-C inclusion complexes were prepared by a solvent evaporation method using a rotary evaporator and various solvents of different dielectric constant such as ethanol, methanol and distilled deionized water to investigate the effect of solvent polarity on the stability of vitamin-C. To estimate the stability of inclusion complexes, samples were stored in a 50 mM phosphate buffer solution of pH 7.0 for 24 hours at
and the degradation rate of vitamin-C was calculated using a high performance liquid chromatography. The stability of vitamin-C was observed to improve with the increase of solvent polarity.
Stability Evaluation of Vitamin-C Inclusion Complexes Prepared using Supercritical ASES Process
Yang, Jun-Mo ; Kim, Seok-Yun ; Han, Ji-Hyun ; Jung, In-Il ; Ryu, Jong-Hoon ; Lim, Gio-Bin ;
KSBB Journal, volume 21, issue 2, 2006, Pages 157~163
A supercritical fluid process, called aerosol solvent extraction system(ASES), is especially suitable to the pharmaceutical, cosmetic and food industries due to its environmentally-friendly, non-toxic and residual solvent-free properties. In particular, the application of the ASES process to the processing of thermo-labile bioactive compounds has received attention of many scientists and engineers because of its low-temperature operating conditions. Unstable substances such as Vitamin-C and Vitamin-A can be effectively protected from degradation during the preparation process, because the ASES process is free from oxygen and moisture. In this study, Vitamin-C was formulated with 2-hydroxypropyl-
-CD) for enhancement of Vitamin-C stability and bioavailability using the ASES process. To investigate the influence of the preparation process on the stability of Vitamin-C, Vitamin-C/HP-
-CD inclusion complexes were prepared using both conventional solvent evaporation method and ASES process, and stored in a 50 mM phosphate buffer solution of pH 7.0 at
for 24 hours. From the experimental results, the stability of the Vitamin-C/HP-
-CD inclusion complex prepared from the ASES process was found to be much higher than that of pure Vitamin-C and the Vitamin-C/HP-
-CD inclusion complex prepared by the solvent evaporation method. The stability of Vitamin-C was observed to increase with the decrease of temperature at a constant pressure or with the increase of pressure at a constant temperature.
Screening of Antioxidative and Antibacterial Activity from Hot Water Extracts of Indigenous Plants, Jeju-Island
Moon, Yonng-Gun ; Choi, Kwang-Sik ; Lee, Kyeong-Jun ; Kim, Ki-Young ; Heo, Moon-Soo ;
KSBB Journal, volume 21, issue 2, 2006, Pages 164~169
In this study, we investigated the biological activity of antioxidant and antibacterial activity of Indigenous Plants, Jeju-Island., which, using water were extracted. The reducing activity on the 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical and
and OH radical scavenging potential, in search for antioxidation activities of Indigenous Plants, were sequentially screened. Among the ten plant parts, Prunella vulgaris var. aleutica Fernald. flower had the highest antioxidative activity. Hot water extracts of ten indigenous plants were screened for antibacterial activity 13 fish pathogenic bacteria by agar diffusion method. Among the various Hot water extracts, the Prunella vulgaris var. aleutica Fernald, Gleichenia japonica Spreng, Microlepia marginata(panzer) Christ., Perilla frutescens var. japonica Hara. showed relatively strong antibacterial activities in the order.