Escherichia coli is engineered to grow on CO and formic acid.

We engineered Escherichia coli to grow on CO and formic acid alone by introducing the synthetic CO and formic acid assimilation pathway, expressing two formate dehydrogenase genes, fine-tuning metabolic fluxes and optimizing the levels of cytochrome bo and bd-I ubiquinol oxidase. Our engineered strain can grow to an optical density at 600 nm of 7.38 in 450 h, and shows promise as a platform strain growing on CO and formic acid alone.