Terpenoids represent the largest class of natural products, some of which are resources for pharmaceuticals, fragrances, and fuels. Generally, mass production of valuable terpenoid compounds is hampered by their low production levels in organisms and difficulty of chemical synthesis. Therefore, the development of microbial biosynthetic platforms represents an alternative approach. Although microbial terpenoid-production platforms have been established in Escherichia coli and yeast, an optimal platform has not been developed for Streptomyces species, despite the large capacity to produce secondary metabolites, such as polyketide compounds. To explore this potential, we constructed a terpenoid-biosynthetic platform in Streptomyces reveromyceticus SN-593. This strain is unique in that it harbors the mevalonate gene cluster enabling the production of furaquinocin, which can be controlled by the pathway specific regulator Fur22. We simultaneously expressed the mevalonate gene cluster and subsequent terpenoid-biosynthetic genes under the control of Fur22. To achieve improved fur22 gene expression, we screened promoters from S. reveromyceticus SN-593. Our results showed that the promoter associated with rvr2030 gene enabled production of 212 ± 20 mg/L botryococcene to levels comparable to those previously reported for other microbial hosts. Given that the rvr2030 gene encodes for an enzyme involved in the primary metabolism, these results suggest that optimized expression of terpenoid-biosynthetic genes with primary and secondary metabolism might be as important for high yields of terpenoid compounds as is the absolute expression level of a target gene(s).
|Number of pages||11|
|Journal||ACS Synthetic Biology|
|State||Published - Dec 15 2017|
Bibliographical noteFunding Information:
We thank M. Tanaka for conducting 2-D gel electrophoresis and MALDI-TOF/MS analysis, and Dr. N. Dohmae and T. Suzuki for LC−MS/MS. We are grateful to Dr. S. Okada for providing botryococcene standard. We thank Dr. H. Ikeda and Dr. H. Onaka for pKU492Acos and pTYM19 vectors, respectively. We thank Dr. J. Ishikawa and Dr. A. Toyoda for genome sequence analysis of S. reveromyceticus SN-593. This work was supported by JSPS KAKENHI Grant Number 17H05455 and “Project focused on developing key technologies for discovering and manufacturing drugs for next-generation treatment and diagnosis” from the Japan Agency for Medical Research and Development (AMED).
© 2017 American Chemical Society.
- metabolic engineering
- optimized gene expression
- transcriptional regulator
ASJC Scopus subject areas
- Biomedical Engineering
- Biochemistry, Genetics and Molecular Biology (miscellaneous)