Metabolic engineering of Escherichia coli for the biosynthesis of various phenylpropanoid derivatives

• Construction of a library of 8 biosynthetic bricks for combinatorial biosynthesis.
• Combinatorial biosynthesis of 12 bioactive molecules in E. coli.
• Total biosynthesis of the bioactive natural products piceatannol and pinosylvin.
• Total biosynthesis of the turmeric components curcumin and bisdemethoxycurcumin.

Plants produce a variety of natural products with promising biological activities, such as the phenylpropanoids resveratrol and curcumin. While these molecules are naturally assembled through dedicated plant metabolic pathways, combinatorial biosynthesis has become an attractive tool to generate desired molecules. In this work, we demonstrated that biosynthetic enzymes from different sources can be recombined like legos to make various molecules. Seven biosynthetic genes from plants and bacteria were used to establish a variety of complete biosynthetic pathways in Escherichia coli to make valuable compounds. Different combinations of these biosynthetic bricks were made to design rationally various natural product pathways, yielding four phenylpropanoid acids (cinnamic acid, p-coumaric acid, caffeic acid, and ferulic acid), three bioactive natural stilbenoids (resveratrol, piceatannol and pinosylvin), and three natural curcuminoids (curcumin, bisdemethoxycurcumin and dicinnamoylmethane). A curcumin analog dicaffeoylmethane was synthesized by removing a methyltransferase from the curcumin biosynthetic pathway. Furthermore, introduction of a fungal flavin-dependent halogenase into the resveratrol biosynthetic pathway yielded a novel chlorinated molecule 2-chloro-resveratrol. This work thus provides a novel and efficient biosynthetic approach to creating various bioactive molecules. Further expansion of the library of the biosynthetic bricks will provide a resource for rational design of various phenylpropanoids via the combinatorial biosynthesis approach.