Engineering a Synthetic Pathway for Tyrosol Synthesis in Escherichia coli

Tyrosol is an aromatic compound with great value that is widely used in the food and pharmaceutical industry. In this study, we reported a synthetic pathway for converting p-coumaric acid (p-CA) into tyrosol in Escherichia coli. We found that the enzyme cascade comprising ferulic acid decarboxylase (FDC1) from Saccharomyces cerevisiae, styrene monooxygenase (SMO), styrene oxide isomerase (SOI) from Pseudomonas putida, and phenylacetaldehyde reductase (PAR) from Solanum lycopersicum could efficiently synthesize tyrosol from p-CA with a conversion rate over 90%. To further expand the range of substrates, we also introduced tyrosine ammonia-lyase (TAL) from Flavobacterium johnsoniae to connect the synthetic pathway with the endogenous l-tyrosine metabolism. We found that tyrosol could be efficiently produced from glycerol, reaching 545.51 mg/L tyrosol in a tyrosine-overproducing strain under shake flasks. In summary, we have established alternative routes for tyrosol synthesis from p-CA (a potential lignin-derived biomass), glucose, and glycerol.