sb7b00249_si_001.pdf (1.1 MB)
Development of a Terpenoid-Production Platform in Streptomyces reveromyceticus SN-593
journal contribution
posted on 2017-10-11, 20:03 authored by Ammara Khalid, Hiroshi Takagi, Suresh Panthee, Makoto Muroi, Joe Chappell, Hiroyuki Osada, Shunji TakahashiTerpenoids
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).