Acetoin production in Enterobacter aerogenes by control of PTS independent glucose oxidative pathway
- 주제(키워드) Acetoin , Enterobacter aerogenes , 2-ketogluconate , PTS independent glucose oxidative pathway
- 발행기관 고려대학교 대학원
- 지도교수 오민규
- 발행년도 2016
- 학위수여년월 2016. 8
- 학위구분 석사
- 학과 대학원 화공생명공학과
- 원문페이지 49 p
- 실제URI http://www.dcollection.net/handler/korea/000000069526
- 본문언어 영어
- 제출원본 000045881689
초록/요약
Acetoin, naturally in some fruits and dairy products, is mainly used for flavor enhancer and precursor of platform chemical in many industries. Enterobacter aerogenes was used for acetoin production in this study. budC and dhaD genes encoding acetoin reductase was deleted by metabolic engineering. And then, 2-ketogluconate was removed by deletion of the gcd gene encoding glucose dehydrogenase activated by PTS independent glucose oxidative pathway under continuous aerobic culture condition. In this way, engineered strain was developed to produce acetoin. This completed strain was cultured in flask batch and fed-batch fermentation. As a result, the acetoin reached 62.8g/L in 24h during fed-batch fermentation. This is until now the highest titer of acetoin in Enterobacter species. This research demonstrated the importance of blocking PTS independent glucose oxidative pathway for acetoin production in Enterobacter aerogenes.
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ABSTRACT
1. Introduction
1.1 Application of acetoin
1.2 Ways of acetoin production
1.3 Enterobacter aerogenes is potential strain of acetoin production
1.4 Control of by-products and aeration level
2. Materials and methods
2.1 Strains, plasmids and primers
2.2 Media and culture conditions
2.3 Analytical methods
3. Results
3.1 Control of acetoin production pathway
3.1.1 Deletion of budC gene encoding acetoin reductase
3.1.2 Control of redox balance by aeration level
3.1.3 Deletion of dhaD gene encoding putative acetoin reductase
3.2 Control of PTS independent glucose oxidative pathway
3.2.1 Accumulated 2-ketogluconate in high aerobic condition
3.2.2 Deletion of gcd gene encoding glucose dehydrogenase
3.2.3 Fed-batch fermentation in optimized Enterobacter aerogenes (EJW-03) for acetoin production
4. Discussion
REFERENCES
