서지주요정보
NADH 동시재생을 이용한 실관효소반응기에서의 L-leucine 생산 = L-leucine production with simultaneous NADH regeneration in a hollow fiber enzyme reator
서명 / 저자 NADH 동시재생을 이용한 실관효소반응기에서의 L-leucine 생산 = L-leucine production with simultaneous NADH regeneration in a hollow fiber enzyme reator / 이윤영.
저자명 이윤영 ; Lee, Yun-Young
발행사항 [대전 : 한국과학기술원, 1992].
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소장정보

등록번호

8003024

소장위치/청구기호

학술문화관(문화관) 보존서고

MCE 92030

SMS전송

도서상태

이용가능

대출가능

반납예정일

초록정보

The use of NAD(H)-dependent oxidoreductases as catalysts for large-scale asymmetric syntheses of a host of specialty chemicals requirs efficient and economical procedure for in situ regeneration of the expensive cofactor. Multienzyme reaction systems with a simultaneous coenzyme regeneration have been developed for the production of several L-amino acids in a continuously operated membrane reactor. For L-leucine production from $\alpha$-ketoisocaproate, leucine dehydronase (L-leucine : NADH oxidoreductase, EC1.4.1.9, from bacillus species), formate dehydrogenase (formate : $NAD^+$ oxidoreductase, EC1.2.1.2, from pseudomonas oxalaticus), and $NAD^+$ covalently bound to water-soluble dextran (dextran-$NAD^+$) as the catalytic enzyme, coenzyme regeneration enzyme, and coenzyme, respectively, were used in a hollow fiber enzyme reactor. The sustrates, formate and $\alpha$-ketoisocaproic acid, were pumped through a membrane reactor containing the FDH, LeuDH, and dextran-$NAD^+$ : the product, L-leucine, was continuously ultrafiltered and collected while the high molecular weight enzymes and cofactor analog were retained in the reactor. The experiment was carried out in phospate buffer containing 30 mmol/L sodium $\alpha$-ketoisocaproate and 0.3 mol/L ammonium formate with a residence time of about 1 h. The activity of LeuDH and FDH used was about 5 unit/mL. The continuous production of L-leucine in a hollow fiber enzyme reactor for 34 hrs resulted in a space-time yield of 78.2 g/L/d (or 596 mmol/L/d) with a mean substrate conversion of 76%. The reaction was finished by loss of enzyme activity. Either the enzymes were degraded or cleaved into subunits. The loss of enzymes would be due to irreverseble adsorption onto the membrane. The turnover number of cofactor-ratio of moles of product to moles of NAD(H) - exceeded 8,500. Without the regeneration system, the $NAD^+$ cost per kg leucine production is \$1215/kg. By mean of the regeneration method, the cost reduced to 14 cents/kg, an enormous 10,000-fold reduction. As a result, the high cofactor costs in oxidoreductases reactor had been overcome with efficient in situ regeneration. The cofactor regeneration scheme for NAD(H) had been succesful to the extent that cofactor was no longer the dominant cost in leucine production.

서지기타정보

서지기타정보
청구기호 {MCE 92030
형태사항 x, 64 p. : 삽도 ; 26 cm
언어 한국어
일반주기 부록 수록
저자명의 영문표기 : Yun-Young Lee
지도교수의 한글표기 : 장호남
지도교수의 영문표기 : Ho-Nam Chang
학위논문 학위논문(석사) - 한국과학기술원 : 화학공학과,
서지주기 참고문헌 : p. 53-59
주제 Catalysts.
효소. --과학기술용어시소러스
촉매. --과학기술용어시소러스
Enzymes.
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