Biosynthesis of isoprenoids via the 1-deoxy-D-xylulose-5-phosphate (DXP) pathway requires equimolar glyceraldehyde 3-phosphate and pyruvate to divert carbon flux toward the products of interest. Here, we demonstrate that precursor balancing is one of the critical steps for the production of isoprenoids in Escherichia coli. First, the implementation of the synthetic lycopene production pathway as a model system and the amplification of the native DXP pathway were accomplished using synthetic constitutive promoters and redesigned 5′-untranslated regions (5′-UTRs). Next, fine-controlled precursor balancing was investigated by tuning phosphoenolpyruvate synthase (PpsA) or glyceraldehyde 3-phosphate dehydrogenase (GAPDH). The results showed that tuning-down of gapA improved the specific lycopene content by 45% compared to the overexpression of ppsA. The specific lycopene content in the strains with down-regulated gapA increased by 97% compared to that in the parental strain. Our results indicate that gapA is the best target for precursor balancing to increase biosynthesis of isoprenoids.
Bibliographical noteFunding Information:
This research was supported by the National Research Foundation of Korea (NRF-2015R1A2A1A10056126 and ABC-2010-0029800) funded by the Ministry of Science, ICT & Future Planning and the Gyeongbuk Sea Grant Program, funded by the Ministry of Oceans and Fisheries, Korea.
© 2016 International Metabolic Engineering Society
- Precursor balancing
ASJC Scopus subject areas
- Applied Microbiology and Biotechnology