Production of kaempferol 3-O-rhamnoside from glucose using engineered Escherichia coli.

Flavonoids are ubiquitous phenolic compounds and at least 9,000 have been isolated from plants. Most flavonoids have been isolated and assessed in terms of their biological activities. Microorganisms such as Escherichia coli and Saccharomyces cerevisiae are efficient systems for the synthesis of flavonoids. Kaempferol 3-O-rhamnoside has notable biological activities such as the inhibition of the proliferation of breast cancer cells, the absorption of glucose in the intestines, and the inhibition of the self-assembly of beta amyloids. We attempted to synthesize kaempferol 3-O-rhamnoside from glucose in E. coli. Five flavonoid biosynthetic genes [tyrosine ammonia lyase (TAL), 4-coumaroyl CoA ligase (4CL), chalcone synthase (CHS), flavonol synthase (FLS), and flavonol 3-O-rhamnosyltransferase (UGT78D1)] from tyrosine were introduced into E. coli that was engineered to increase tyrosine production. By using this approach, the production of kaempferol 3-O-rhamnoside increased to 57 mg/L.