Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6490826 | Journal of Biotechnology | 2015 | 8 Pages |
Abstract
The ent-kaurene is a dedicated precursor pool and is responsible for synthesizing natural sweeteners such as steviol glycosides. In this study, to produce ent-kaurene in Escherichia coli, we modularly constructed and expressed two ent-kaurene genes encoding ent-copalyl diphosphate synthase (CPPS) and ent-kaurene synthase (KS) from Stevia rebaudiana known as a typical plant producing steviol glycoside. The CPPS and KS from S. rebaudiana were functionally expressed in a heterologous host E. coli. Furthermore, in order to enhance ent-kaurene production in E. coli, six geranylgeranyl diphosphate synthases (GGPPS) from various microorganisms and eight strains of E. coli as host were compared by measuring ent-kaurene production. The highest ent-kaurene production of approximately 41.1Â mg/L was demonstrated in E. coli strain MG1655 co-expressing synthetic CPPS-KS module and GGPPS from Rhodobacter sphaeroides. The ent-kaurene production was further increased up to 179.6Â mg/L by overexpression of the three key enzymes for isoprenoid precursor, 1-deoxyxylulose-5-phosphate synthase (DXS), farnesyl diphosphate synthase (IspA) and isopentenyl diphosphate isomerase (IDI) from E. coli. Finally, the highest titer of ent-kaurene (578Â mg/L) with a specific yield of ent-kaurene of 143.5Â mg/g dry cell weight was obtained by culturing E. coli strain MG1655 co-expressing the ent-kaurene module, DXS, IDI and IspA in 1Â L bioreactor containing 20Â g/L glycerol.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Bioengineering
Authors
Min Kyung Kong, Hyun-Jun Kang, Jin Ho Kim, Soon Hwan Oh, Pyung Cheon Lee,