Engineering artificial metabolic pathways for biosynthesis

Increasing energy costs and environmental concerns have stimulated the development of sustainable approaches to the replacement of petrochemical processes. Metabolic engineering is a promising strategy that has enormous potential to produce bio-based products from simple, renewable, and inexpensive raw materials. Traditionally, biosynthesis is enabled by overexpressing product-specific enzymes or pathways in organisms that can be easily engineered. To expand the scope of fermentation products, there is a growing trend in designing artificial metabolic pathways through combinatorially screening or engineering enzymes from different sources into a single host. Here we review recent advances in the construction of novel biosynthetic routes, with a particular focus on ketoacid, fatty acid and isoprenoid pathways.

► A summary of recent progress on constructing artificial metabolic pathways.
► Synthetic pathways derived from ketoacids are discussed.
► Strategies to expand the fatty acid pathway are reviewed.
► Advances in artificially manipulating the isoprenoid pathway are summarized.