Research Projects

The study focuses on the engineering of heterologous sesquiterpenoid production in bacterial systems, but the main challenge is the intracellular accumulation of non-native sesquiterpinoids to toxic levels due to insufficient extracellular transport. Despite attempts to address this issue by expressing native or heterologous efflux pumps in E. coli, no sesquiterpenoid-specific native efflux pumps have been identified in either E. coli or new potential bacterial systems. Azospirillum brasilense, which has an endogenous high-flux isoprenoid pathway, has been engineered to improve the flux, producing more than 2 g/L carotenoids. However, this system only produces 40 mg/L α-humulene and 65 mg/L valencene, which is less than 5% of the carotenoid yield. This suggests that over 95% of the isopreprenoid flux is still available, which can be utilized to improve yields. The study proposes engineering the extracellular transport of sesquiterpenoids in A. brasilense to improve yields by using α-humulene and valencene as model compounds. The main focus will be on transcriptome-based identification of sesquiterpenoid-induced endogenous efflux pumps and optimizing their expression to improve the extracellular transport of non-native sesquiterpenoids.