The plant polymer lignin is the greatest source of aromatic chemical structures on earth. Hence, the chemically diverse lignin monomers are valuable raw materials for fine chemicals, materials synthesis, and food and flavor industries. However, extensive use of this natural resource is hampered by the large number of different lignin monomers and the complex and irregular structure of lignin, which renders current processes for its chemical or enzymatic degradation inefficient. The microbial production of lignin monomers from renewable resources represents a promising alternative to lignin degradation, which could meet the demand for aromatic chemical structures. In this study, we describe the functional introduction of an artificial phenylpropanoid pathway into Escherichia coli, achieved by transferring several genes from plants and microbes. The established chimeric pathway efficiently converts l-tyrosine into the lignin precursor molecule p-coumaryl alcohol.
