(228bf) Engineering E. coli for Methanol Metabolism

Authors: 
Stephanopoulos, G., Massachusetts Institute of Technology
King, J., MIT
Reiter, M., MIT
Due to the volatility of sugar prices, growing concerns in the â??food vs fuelâ? debate, and the recent relatively low cost of natural gas, methanol has emerged as a promising feedstock for bio-based manufacturing of fuels and chemicals. Organisms that natively efficiently metabolize methanol are not generally amenable to metabolic engineering, owing to poorly developed genetic tools, and an incomplete understanding of their physiology, biochemistry and regulation. By contrast, E. coli, the workhorse of metabolic engineering, does not natively consume methanol. Here we present progress in engineering E. coli to grow and produce a variety of target molecules toward from methanol. Using isotopically labeled methanol, we demonstrate the ability of an engineered strain to assimilate methanol into central carbon metabolism. We further demonstrate the improvement of the assimilation rate through rational strain engineering based on sensitivity analysis of an experimentally parameterized kinetic model. Finally, we report on the effects of methanol supplementation on growth rate, yield, and product titer. The results lay the foundation for the development of an E. coli strain that can be â??dropped inâ? to existing bioprocesses to enable the utilization of the alternative substrate.