Synthetic biosensor accelerates evolution by rewiring carbon metabolism toward a specific metabolite

Proper carbon flux distribution between cell growth and production of a target compound is important for biochemical production because improper flux reallocation inhibits cell growth, thus adversely affecting production yield. Here, using a synthetic biosensor to couple production of a specific metabolite with cell growth, we spontaneously evolve cells under the selective condition toward the acquisition of genotypes that optimally reallocate cellular resources. Using 3-hydroxypropionic acid (3-HP) production from glycerol in Escherichia coli as a model system, we determine that mutations in the conserved regions of proteins involved in global transcriptional regulation alter the expression of several genes associated with central carbon metabolism. These changes rewire central carbon flux toward the 3-HP production pathway, increasing 3-HP yield and reducing acetate accumulation by alleviating overflow metabolism. Our study provides a perspective on adaptive laboratory evolution (ALE) using synthetic biosensors, thereby supporting future efforts in metabolic pathway optimization.
This research was supported by the C1 Gas Refinery Program (NRF-2018M3D3A1A01055754 and NRF-2015M3D3A1A01064882), the Global Research Laboratory Program (NRF-2016K1A1A2912829), and the Bio & Medical Technology Development Program (NRF-2018M3A9H3020459) through the National Research Foundation of Korea (NRF of Korea), funded by the Ministry of Science and ICT (MSIT). S.W.S. is partially supported by the Creative-Pioneering Researchers Program through Seoul National University (SNU).