Production of phenylpropanoids and flavonolignans from glycerol by metabolically engineered Escherichia coli.

Phenylpropanoids are a group of plant natural products with medicinal importance derived from aromatic amino acids. Here, we report the production of two representative phenylpropanoids-coniferyl alcohol (CA) and dihydroquercetin (DHQ)-from glycerol by engineered Escherichia coli. First, an E. coli strain capable of producing 187.7 mg/L of CA from glycerol was constructed by the introduction of hpaBC from E. coli and OMT1, 4CL4, and CCR1 from Arabidopsis thaliana to the p-coumaric acid producer. Next, an E. coli strain capable of producing 239.4 mg/L of DHQ from glycerol was constructed by the introduction of F3H, TT7, and CPR from A. thaliana to the naringenin producer, followed by engineering the signal peptide of a cytochrome P450 TT7. Furthermore, to demonstrate the production of flavonolignans, a group of heterodimeric phenylpropanoids, from glycerol, ascorbate peroxidase 1 from Silybum marianum was employed and engineered to produce 0.04 µg/L of silybin and 1.29 µg/L of isosilybin from glycerol by stepwise culture. Finally, a single strain harboring all the 16 necessary genes was constructed, resulting in 0.12 µg/L of isosilybin production directly from glycerol. The strategies described here will be useful for the production of pharmaceutically important yet complex natural products.