Immobilization of cephalexin semisynthesizing enzyme = 세팔렉신 반합성 효소의 고정화

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To immobilize partially purified cephalosporin acylase from Xanthomonas citri IFO 3835, various immobilization methods were tested. From these experiments, adsorption onto bentonite was selected as cephalosporin acylase immobilization method. From optimization experiments of adsorption conditions, 5 mg betonite/ml and 6-7 mg protein/ml of enzyme concentration were selected as optimum conditions of bentonite adsorption. And adsorption was performed at 20℃ by intermittent stirring at intervals of 5 minutes. Enzyme immobilized by the above method was investigated for its characteristics. The optimum pH and temperature of immobilized enzyme reaction were identical with free enzyme as pH 6.5 and 35℃, respectively. But immobilized enzyme was more stable than free enzyme in pH change and at higher temperature. Thus the pH profile of immobilized enzyme was broader than free enzyme, and the half lives of immobilized enzyme and free enzyme at 35℃ were 360 hours and 8 hours, respectively. The substrate inhibition by 7-ADCA was reduced by immobilization Namely, the maximum initial reaction rates of immobilized enzyme and free enzyme were obtained at 7-ADCA concentration of 50 mM and 40 mM, respectively. In enzyme reactor operation, the immobilized enzyme was repeatedly used in a batch type enzyme reactor of stirred tank. By continuous feeding of PGM into enzyme reactor, the conversion ratio was significantly improved when the flow rate of PGM was 1 mM/min at the enzyme loading of 0.5 uit/ml.
Advisors
Kim, Jung-HoeresearcherRhee, Joon-Shickresearcher김정회researcher이준식researcher
Description
한국과학기술원 : 생물공학과,
Publisher
한국과학기술원
Issue Date
1988
Identifier
66141/325007 / 000861038
Language
eng
Description

학위논문(석사) - 한국과학기술원 : 생물공학과, 1988.8, [ ix, 93 p. ]

URI
http://hdl.handle.net/10203/28299
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=66141&flag=dissertation
Appears in Collection
BS-Theses_Master(석사논문)
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