• 대한약학회:학술대회논문집
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• 대한약학회 2001년도 Proceedings of International Convention of the Pharmaceutical Society of Korea
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• pp.135.1-135.1
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• 2001

• 대한약학회:학술대회논문집
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• 대한약학회 2000년도 춘계총회 및 학술대회
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• pp.113.2-113.2
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• 2000

• Korean Chemical Engineering Research
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• 제55권2호
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• pp.237-241
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• 2017

아세토인(acetoin)은 식품과 화학산업에서 플랫폼 물질로 이용되며 산업적으로 다양한 응용이 가능한 물질이다. 본 연구에서는 대사공학(metabolic engineering)을 이용하여 아세토인의 생산량이 증가한 재조합 Klebsiella pneumoniae를 구축하였다. 우선 2,3-부탄디올(2,3-butanediol)생산을 위해 제작되었던 재조합 K. pneumoniae (KMK-05)에서 두 가지 2,3-butanediol dehydrogenase (budC, dhaD)를 유전체에서 제거하여 아세토인 생산량을 늘리고, 전사인자 중 하나인 AcoK를 제거하여 아세토인을 분해하는 효소의 발현량을 줄였다. 그리고 NADH oxidase를 발현시켜 세포 내 산화 환원 균형(redox balance)을 맞춰 대사흐름을 개선하였다. 이렇게 대사공학을 통해 구축된 재조합 Klebsiella pneumoniae(KJW-03-nox)로 아세토인 생산량과 수율을 높였고, 36시간 동안의 유가식 배양을 진행하여 51 g/L의 아세토인 농도와 최대 생산성 2.6 g/L/h을 달성하였다.

• Journal of Plant Biology
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• 제39권4호
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• pp.295-300
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• 1996

The physiological effects of oligogalacturonic acid (OGA:D. P. 6-7), a product of acid hydrolysis of polygalacturonic acid (PGA), on ethylene biosynthesis in mung bean (Vigna radiata W.) hypocotyl segments was studied. Among PGA, OGA and monogalacturomic acid (MGA), only OGA stimulated ethylene production in mung bean hypocotyl segments, and the most effective concentraton of OGA was 50$\mu\textrm{g}$/mL. Time course data indicated that this stimulatiion effect of OGA appeared after 90 min incubation period and continued until 24 h. When indol-3-acetic acid (IAA) and 1-aminocyclopropane-1-carboxylic acid (ACC) were treated with OGA to investigate the mechanism of OGA on ethylene production, they did not show synergistic effects on ethylene production. The stimulation of ethylene production by OGA was due to the increase of in vivo ACC synthase activity, but OGA treatment had no effect of in vivo ACC oxidase activity. The effect of aminoethoxy vinyl glycine (AVG) and Co2+, the inhibitor of ethylene synthesis, was siminished a little by the OGA, but the treatment of Ca2+, known to increase ACC, with OGA did not increase the ethylene production, this effect seems to be specific for Ca2+ because other divalent cation, Mg2+, did not show the inhibition of OGA-indyuced ethylene production. It is possible that the OGA adopts a different signal transduction pathway to the ethylene bioxynthesis.

• 한국미생물·생명공학회지
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• 제50권4호
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• pp.557-562
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• 2022

본 연구에서는 토양, 담수 및 염수 퇴적물, 슬러지 등 8종의 접종원을 이용하여 배양인자(기질종류, 염농도, 배양온도)에 따른 바이오수소 생산 잠재능을 평가하고 최적조건을 도출하고자 하였다. 각 접종원 별 바이오수소 생산속도는 배양온도와 접종원 종류에 의해 유의한 영향을 받았다. 반면 기질종류와 염농도는 바이오수소 생산속도에 대체로 유의한 영향을 끼치지 않았다. 고온(50°)보다 중온(37℃)의 배양 온도가 수소 생산에 더 적합하였으며, 8종의 접종원 중에서 중에서는 혐기소화슬러지의 수소 생산능이 가장 우수하였다. 혐기소화슬러지의 최대 수소 생산속도는 중온(37℃)과 고온(50℃)에서 각각 2,729.0 및 1,384.7 ml-H₂·l^-1·d^-1였다.

• KSBB Journal
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• 제20권4호
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• pp.278-284
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• 2005

식물세포의 느린 생장과 낮은 생산량의 이유로 지금까지 는 주로 미생물이나 동물세포에서 유전자 재조합 단백질을 생산하여 왔다. 그러나 저렴한 배지 가격, 동물 유래 바이러스 감염 위험성으로부터의 안정성, glycosylation 등의 post-translational modification이 가능하다는 장점들로 인하여 최근 들어 식물세포배양은 생물학적 활성을 가진 고부가가치의 단백질을 생산하는데 많이 이용되고 있다. 본 연구에서는 생장배지에 첨가했던 sucrose의 소비와 induction 배지로의 교환에서 오는 배지내의 삼투압을 조절하여 hCTLA4-Ig의 생산성을 높이고자 하였다. 다양한 삼투압 조절제 첨가 실험을 통해 sorbitol을 선별하고, 40 mM의 sorbitol 첨가에서 상대적으로 높은 생존도와 induction 후 7일째 대조구보다 1.7배 높은 생산성을 확인하였다. 또한, 저농도의 glucose 첨가를 통한 생산성 증대에 있어서는 8 mM glucose에서 induction 이후에도 높은 세포농도를 유지하면서 최대 37.3 mg/L까지 hCTLA4-Ig 생산량을 증가시켰다. 5-L bioreactor에서 회분식 배양과 induction시의 hCTLA4-Ig 생산량을 비교한 결과 induction시 배양 18일째 최고 45.3 mg/L까지 높일 수 있었으며, 회분식 배양에 비해 2.1배 증가됨을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.712-720
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• 2007

To investigate clonal variations of recombinant Chinese hamster ovary(rCHO) clones in response to culture pH and temperature, serum-free suspension cultures of two antibody-producing CHO clones(clones A and B), which were isolated from the same parental clone by the limiting dilution method, were performed in a bioreactor at pH values in the range of 6.8-7.6, and two different temperatures, $33^{\circ}C\;and\;37^{\circ}C$. In regard to cell growth, clone A and clone B displayed similar responses to temperature, although their degree of response differed. In contrast, clones A and B displayed different responses to temperature in regard to antibody production. In the case of clone A, no significant increase in maximum antibody concentration was achieved by lowering the culture temperature. The maximum antibody concentration obtained at $33^{\circ}C$(pH 7.4) and $37^{\circ}C$(pH 7.0) were $82.0{\pm}2.6$ and $73.2{\pm}4.1{\mu}g/ml$, respectively. On the other hand, in the case of clone B, an approximately 2.5-fold increase in maximum antibody concentration was achieved by lowering the culture temperature. The enhanced maximum antibody concentration of clone B at $33^{\circ}C$($132.6{\pm}14.9{\mu}g/ml$ at pH 7.2) was due to not only enhanced specific antibody productivity but also to prolonged culture longevity. At $33^{\circ}C$, the culture longevity of clone A also improved, but not as much as that of clone B. Taken together, CHO clones derived from the same parental clone displayed quite different responses to culture temperature and pH with regards antibody production, suggesting that environmental parameters such as temperature and pH should be optimized for each CHO clone.

• Journal of Applied Biological Chemistry
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• 제56권2호
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• pp.119-129
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• 2013

Thirteen different Streptomyces isolates were evaluated for their ability to produce keratinase using chicken feather as a sole carbon and nitrogen sources under solid state fermentation (SSF). Streptomyces sp. NRC 13S produced the highest keratinase activity [1,792 U/g fermented substrate (fs)]. The phenotypic characterization and analysis of 16S rDNA sequencing of the isolate were studied. Optimization of SSF medium for keratinase production by the local isolate, Streptomyces sp. NRC13S, was carried out using the one-variable-at-a-time and the statistical approaches. In the first optimization step, the effect of incubation period, initial moisture content, initial pH value of the fermentation medium, and supplementation of some agro-industrial by-products on keratinase production were evaluated. The strain produced about 2,310 U/gfs when it grew on chicken feather with moisture content of 75% (w/w), feather: fodder yeast ratio of 70:30 (w/w), and initial pH 7 using phosphate buffer after 8 days. Based on these results, the Box-Behnken design and response surface methodology were applied to find out the optimal conditions for the enzyme production. The corresponding maximal production of keratinase was about 2,569.38 U/gfs.

• 한국미생물·생명공학회지
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• 제50권2호
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• pp.245-254
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• 2022

Cellulases are a group of biocatalyst enzymes that are capable of degrading cellulosic biomass present in the natural environment and produced by a large number of microorganisms, including bacteria and fungi, etc. In the current study, we isolated, screened and characterized cellulase-producing bacteria from soil. Three cellulose-degrading species were isolated based on clear zone using Congo red stain on carboxymethyl cellulose (CMC) agar plates. These bacterial isolates, named as HB2, HS5 and HS9, were subsequently characterized by morphological and biochemical tests as well as 16S rRNA gene sequencing. Based on 16S rRNA analysis, the bacterial isolates were identified as Bacillus cerus, Bacillus subtilis and Bacillus stratosphericus. Moreover, for maximum cellulase production, different growth parameters were optimized. Maximum optical density for growth was also noted at pH 7.0 for 48 h for all three isolates. Optical density was high for all three isolates using meat extract as a nitrogen source for 48 h. The pH profile of all three strains was quite similar but the maximum enzyme activity was observed at pH 7.0. Maximum cellulase production by all three bacterial isolates was noted when using lactose as a carbon rather than nitrogen and peptone. Further studies are needed for identification of new isolates in this region having maximum cellulolytic activity. Our findings indicate that this enzyme has various potential industrial applications.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2006년도 에너지.가스.기후변화학회 연합춘계학술대회 및 특별심포지움
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• pp.198-201
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• 2006