In vitro metabolic engineering: current status and recent progress

Abstract In vitro metabolic engineering refers to the assembly of multiple purified/partially purified enzymes as well as nonenzyme components such as cofactors according to the designed pathways for the conversion of certain substrates into target compounds without the utilization of cells. Resembling an ingenious machine, in vitro metabolic engineering biosystems (ivMEB) are usually modularized, so that their design, assembly, and regulation processes are highly controllable. Upon rational optimization of reaction conditions for improved system adaptation, ivMEBs can function with high efficiency. Recently, the advantages of ivMEBs on the precise control of reaction process and the enhancement of product yield have suggested their great application potential in biomanufacturing. Studies on ivMEBs have become an important branch of synthetic biology, and are gaining increasing attentions. This chapter systematically reviews the module-based construction strategy of ivMEBs as well as the research progress on improving the adaptability of enzymes and other non-enzyme components within the ivMEBs. The current challenges and future prospects of ivMEBs are also discussed.