Correspondence

Curcuminoids, which are produced specifically by plants of the order Zingiberales, have long been used as food additives because of their aromatic, stimulant and colouring properties and as traditional Asian medicines because of their anti-tumour, antioxidant and hepatoprotective activities. Curcuminoids are therefore attractive targets for metabolic engineering. An artificial curcuminoid biosynthetic pathway, including reactions of phenylalanine ammonia-lyase (PAL) from the yeast Rhodotorula rubra, 4-coumarate:CoA ligase (4CL) from Lithospermum erythrorhizon and curcuminoid synthase (CUS) from rice (Oryza sativa), a type III polyketide synthase, was constructed in Escherichia coli for the production of curcuminoids. Cultivation of the recombinant E. coli cells in the presence of tyrosine or phenylalanine, or both, led to production of bisdemethoxycurcumin, dicinnamoylmethane and cinnamoyl-p-coumaroylmethane. Another E. coli system carrying 4CL and CUS genes was also used for high-yield production of curcuminoids from exogenously supplemented phenylpropanoid acids: p-coumaric acid, cinnamic acid and ferulic acid. The yields of curucminoids were up to ~100 mg l”1. Furthermore, this system gave approximately 60 mg curcumin l”1 from 10 g rice bran pitch, an industrial waste discharged during rice edible oil production, as a source of ferulic acid