http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
이은교,장용근,장호남,김인호 한국산업미생물학회 1995 한국미생물·생명공학회지 Vol.23 No.5
전기투석속도에 영향을 주는 인자로서 전압, 젖산농도, 온도, 젖산염 종류, pH등을 살펴보았다. 전압은 예상대로 전기투석속도에 가장 큰 영향을 주는 인자로 밝혀졌으며, 전압이 높아질수록 전기투석속도가 크게 증가하여 4,6,8 V의 전위차하에서 각각 0.29, 1.81, 4.43 g/h의 평균 전기투석속도를 얻었다. 동일 전압 하에서 source solution 농도가 높아질수록 전기투석속도는 증가하였다. 또한 전기투석실험 말기에 source solution으로부터 침투물 용액으로의 젖산 이동이 두 용액간의 농도차에 의해 제한받는 현상도 관찰되었는데, 이런 현상은 전류에 의한 젖산이온 이동과 농도차에 의한 back-diffusion이 상쇄되기 때문인 것으로 해석되었다. 25℃와 35℃에서의 전기투석실험과에 따르면 10℃ 온도 상승에 대해서 전기투석속도는 약 10% 증가를 보였다. pH를 4.0, 5.0, 6.0로 변화시켜 본 결과, pH 4.0에서의 전기투석속도가 가장 빠르게 나타났고, Na-lactate보다는 NH_4-lactate 형태가 전기투석속도면에서 유리함을 알 수 있었다. 회분식 발효시 전기투석에 의한 in situ 젖산 분리효과를 알아보기 위해 pH 조절만 한 경우, pH 조절없이 전기 투석만 한 경우, pH 조절과 전기투석을 동시에 한 경우 세가지 면에서 살펴보았다. 세가지 경우 중 pH 조절을 하면서 전기투석을 한 발효가 전반적으로 수율이나 생산성 면에서 효과적이었다. 초기 포도당 농도가 50g/l인 경우에는 현저한 차이를 보이지 않았으나, 150g/l인 경우에는 약 1.7배의 생산성 효과를 얻을 수 있었다. Effects of lactate concentration, temperature, counter ions, pH as well as voltage (current) in batch electrodialysis (ED) experiments with a 3-compartment unit were investigated. The applied voltage was found to be the most critical factor as expected. The electrodialysis rate increased with the lactate concentration of the source solution. The amount of lactate transferred was limited by the lactate concentration difference between cathode and permeate compartments. The electrodialysis rate did not heavily depend on temperature change. The electrodialysis rate of NH_4-lactate was faster than that of Na-lactate and both lactates showed the highest electrodialysis rate at a pH of 4.0. A little amount of non-ionic glucose diffused through the anionic membrane to the permeate compartment. To test the effectiveness of the in situ recovery of lactic acid from fermentation broth by ED, three cases of batch culture were carried out; pH control only, ED only, and pH control and ED. The case with both pH control and ED was more efficient than that with pH control only in the aspects of productivity and product yield.
2단계 아세톤 침전법으로부터 얻어진 Candida rugosa Lipase를 이용한(R,S)-Naproxen Methyl Ester의 광학선택성 수화반응
이은교,최순자,정봉현 한국산업미생물학회 2000 한국미생물·생명공학회지 Vol.28 No.4
Candida rugosa 유래 리파제의 광학선택성 증진을 위해 2단계 아세톤 침전법을 개발하였고, 이를 (S)-naproxen의 광학분할에 응용하였다. 2단계 아세톤 처리법에 의해 얻어진 CRL은 아세톤 처리를 하지 않은 효소에 비해 약 2.4배의 활성 증가를 보였고, (R,S)-naproxen methyl ester를 기질로 사용하였을 경우 98%의 enantiomeric excess를 보였다. 2단계 아세톤 침전법으로 얻은 두 번째 분획인 AF-2의 크로마토그램 형태는 crude lipase와 거의 비슷하였고, isoenzyme인 리파제 A와 B가 함께 공존하고 있음을 확인하였다. 광학활성능력이 상대적으로 떨어지는 리파제 B부분만을 2단계 아세톤 침전법으로 분획하여 리파제 B-AF1과 리파제 B-AF2를 얻었고, 이를 naproxen methyl ester의 수화반응에 이용하였다. 그 결과 아세톤 처리후 리파제 B (리파제 B-AF2)의 광학선택성이 급격히 증가하는 것이 확인되었다. A novel two-step acetone treatment method was developed to enhance the enantioselectivity of Candida rugosa lipase (CRL) toward the hydrolysis of racemic naproxen methyl ester. The acetone-treated CRL was considerably more enantioselective than the crude CRL, yielding an enantiomeric excess of 98~100%. The crude and acetone-treated CRLs were subjected to anion exchange chromatography, and their chromatography profiles were compared. In consequence, both chromatography profiles were found to be almost identical, resulting in two separate lipase peaks (lipase A and B). The lipase B. which is known to be less enantioselective, was treated with acetone using a two-step treatment method. The enantioselectivity of acetone-treated lipase B was dramatically increased, yielding an enantiomeric excess of 99%.
프탈이미드계 고수세성 아조 분산염료의 합성과 셀룰로스 아세테이트 섬유에 대한 염색성 연구
이은교,김경학,윤상현,오나현,김상천,고준석 한국섬유공학회 2020 한국섬유공학회지 Vol.57 No.3
In disperse dyeing of polyester fibers, reduction clearing is conducted to improve the wet fastness of the dyed material. However, in the case of disperse dyeing of cellulose diacetate fabrics, when reduction clearing is conducted, the acetyl groups in cellulose acetate fibers may be alkali-hydrolyzed, which leads to a deterioration of their characteristic properties. Therefore, the dyed acetate fabrics are usually after-treated with a soaping agent at a relatively low temperature for better wet fastness, although it fails to meet the customer demands. In this study, high-washable phthalimide-based azo disperse dyes were synthesized, and their dyeing and fastness properties on cellulose diacetate fabrics were investigated. In particular, conventional 4-aminoazobenzene dyes containing a nitro group at the 4-position were synthesized to compare their fastness properties on cellulose acetate with those of phthalimide-based azo disperse dyes.
이은교,장원경,Kyoung Mi Park,Jung Eun Baek,Jin-Ki Park,Joon-Ki Jung,Seung Hui Lee,정봉현 한국생물공학회 2008 Biotechnology and Bioprocess Engineering Vol.13 No.2
The selective removal of impurity proteins and colloidal particles from milk prior to chromatographic purification processes presents a crucial issue in the production of therapeutic proteins from transgenic animals with high recovery yield and purity. We have developed an efficient two-step precipitation method for the recovery of the recombinant human erythropoietin (rhEPO) of interest from transgenic sow milk. Here, rhEPO was partially purified from transgenic sow milk via a two-step precipitation method consisting of ammonium sulfate and divalent metal precipitations, with a yield of approximately 82.1% and a purification fold of 10.4 at a copper concentration of 30 mM. Copper proved to be the strongest flocculating agent among the divalent ions tested for the aggregation of milk proteins under 35%, with ammonium sulfate, zinc, nickel, and calcium demonstrating increasing flocculating capability in the given order. Copper and zinc proved to be appropriate divalent metals for the recovery of rhEPO at high yield and purity, and the optimal concentration ranges of copper and zinc were 20~40 and 40~80 mM, respectively.