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Multistep-enzymatic synthesis of n-heptanoic acid and omega-hydroxyundec-9-enoic acid from ricinoleic acid

Title
Multistep-enzymatic synthesis of n-heptanoic acid and omega-hydroxyundec-9-enoic acid from ricinoleic acid
Authors
송다현
Issue Date
2013
Department/Major
대학원 식품공학과
Publisher
이화여자대학교 대학원
Degree
Master
Advisors
박진병
Abstract
ω-Aminoundecanoic acid is used for the production of polyamide 11, which is frequently used as a cost effective replacement for metal or rubber in highly technical applications. In this study, the microbial production of ω-hydroxyundec-9-enoic acid, which is a precursor in the synthesis of ω-aminoundecanoic acid and also reported as an antifungal substance from leaves of wild rice (Oryza officinalis), was investigated. The microbial process was based on the multi-step bioconversion, which is achieved by a cascade reaction using an alcohol dehydrogenase, a Baeyer-Villiger monooxygenase, and an esterase. Ricinoleic acid was firstly oxidized to 12-keto oleic acid, which is then further oxidized to ester by the recombinant Escherichia coli expressing the alcohol dehydrogenase from Micrococcus luteus and the Baeyer-Villiger monooxygenase from Pseudomonas putida. The ester was finally hydrolyzed by the esterase of P. fluorescens. Investigation of alcohol dehydrogenase and Baeyer-Villiger monooxygenase expression in E. coli BL21 DE3 and biotransformation conditions enabled ω-hydroxyundec-9-enoic acid to accumulate to a final concentration of ca. 7.6 mM in the reaction medium. The specific product formation rate and product yield reached approximately 3.5 U/g CDW and 76%, respectively. This study will contribute to replacement of dangerous chemical processes to green bioprocesses for the production of versatile carboxyl synthons.;ω-Aminoundecanoic acid 는 polyamide 11의 생산에 이용되고 있으며, 비용 측면에서 효율적이기 때문에 금속이나 고무의 대체제로서 널리 쓰여지고 있다. ω-Hydroxyundec-9-enoic acid은 야생벼(Oryza officinalis)의 잎에서 발견되는 항균 물질로 보고되었으며, ω-aminoundecanoic acid을 합성할 수 있는 전구체로 알려져 있다. 본 연구에서는 미생물을 이용하여 이를 생산하는 방법을 연구 하였다. 이 생합성 경로는 alcohol dehydrogenase, Baeyer-Villiger monooxygenase 그리고 esterase 에 의한 단계적인 생물전환 효소 반응에 기초하였다. 첫 번째로 리시놀레산은 재조합 대장균에서 발현된 Micrococcus luteus 유래의 alcohol dehydrogenase와 Pseudomonas putida 유래의 BVMO에 의하여 12-케토 올레산을 거쳐 에스터로 산화되었다. 마지막 단계에서 에스터는 P. fluorescens 유래의 esterase에 의하여 가수 분해 되었다. 대장균에서의 alcohol dehydrogenase와 Baeyer-Villiger monooxygenase의 효과적인 발현조건을 탐색하여 적용한 결과, 반응액에서 ω-hydroxyundec-9-enoic acid가 약 7.6 mM 정도까지 생산 되었다. 이때 Specific product formation rate 와 반응산물의 수율은 각각 약 3.5 U/g CDW 와 76%이었다. 본 연구결과는 환경오염을 야기시키는 화학적인 합성 방법을 환경 친화적인 방법으로 대체하여 다양한 carboxyl synthon 합성에 기여할 것으로 사료된다.
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