From bugs to bioplastics: Total (+)-dihydrocarvide biosynthesis by engineered Escherichia coli

The monoterpenoid lactone derivative (+)‐dihydrocarvide ((+)‐DHCD) can be polymerised to form shape‐memory polymers. Synthetic biology routes from simple, inexpensive carbon sources are an attractive, alternative route over chemical synthesis from (R)‐carvone. We have demonstrated a proof‐of‐principle in vivo approach for the complete biosynthesis of (+)‐DHCD from glucose in Escherichia coli (6.6 mg L−1). The pathway is based on the Mentha spicata route to (R)‐carvone, with the addition of an ′ene′‐reductase and Baeyer–Villiger cyclohexanone monooxygenase. Co‐expression with a limonene synthesis pathway enzyme enables complete biocatalytic production within one microbial chassis. (+)‐DHCD was successfully produced by screening multiple homologues of the pathway genes, combined with expression optimisation by selective promoter and/or ribosomal binding‐site screening. This study demonstrates the potential application of synthetic biology approaches in the development of truly sustainable and renewable bioplastic monomers.