De novo production of benzyl glucosinolate in Escherichia coli.

Microbial production of plant specialised metabolites is challenging as the biosynthetic pathways are often complex and can contain enzymes, which function is not supported in traditional production hosts. Glucosinolates are specialised metabolites of strong commercial interest due to their health-promoting effects. In this work, we engineered the production of benzyl glucosinolate in Escherichia coli. We systematically optimised the production levels by first screening different expression strains and by modification of growth conditions and media compositions. This resulted in production from undetectable to approximately 4.1 μM benzyl glucosinolate, but also approximately 3.7 μM of desulfo-benzyl glucosinolate, the final intermediate of this pathway. Additional optimisation of pathway flux through entry point cytochrome P450 enzymes and PAPS-dependent sulfotransferase increased the production additionally 5-fold to 20.3 μM (equivalent to 8.3 mg/L) benzyl glucosinolate.