Autonomous production of 1,4-butanediol via a de novo biosynthesis pathway in engineered Escherichia coli

• A de novo 1,4-butanediol (BD) biosynthesis pathway was designed and constructed.
• The whole system consists of an enzymatic reactor and a genetic controller.
• Carbon sources were orthogonally utilized for cellular growth and BD production.
• Autonomous BD production was achieved using a quorum sensing system.
• This work showcases the synergy between metabolic engineering and synthetic biology.

1,4-Butanediol (BD) is an important chemical that is widely used in industry with an annual demand of one million metric tons. Here we report a modular development of engineered bacteria for successful BD bio-production. Using a systems engineering concept, we partitioned our development into two parts: namely BD biosynthesis and production control. The former was implemented through a de novo pathway that functions as an enzymatic reactor, while the latter was accomplished via synthetic circuits serving as genetic controllers. To facilitate development, the carbon utilizations were also partitioned into two routes. d-xylose was exclusively designated for BD production with other carbon sources utilized for cellular growth. Additionally, a quorum-sensing mechanism was exploited for production control, and the resulting strain was capable of autonomous production of BD. This study represents an example of the synergy between synthetic biology and metabolic engineering, affirming the need for deeper integration of the two fields.