Optimization of the l -tyrosine metabolic pathway in Saccharomyces cerevisiae by analyzing p -coumaric acid production

In this study, we applied a series of genetic modifications to wild-type S. cerevisiae strain BY4741 to address the bottlenecks in the l -tyrosine pathway. A tyrosine ammonia-lyase (TAL) gene from Rhodobacter capsulatus , which can catalyze conversion of l -tyrosine into p -coumaric acid, was overexpressed to facilitate the analysis of l -tyrosine and test the strain’s capability to synthesize heterologous derivatives. First, we enhanced the supply of precursors by overexpressing transaldolase gene TAL1 , enolase II gene ENO2 , and pentafunctional enzyme gene ARO1 resulting in a 1.55-fold increase in p -coumaric acid production. Second, feedback inhibition of 3-deoxy- d -arabino-heptulosonate-7-phosphate synthase and chorismate mutase was relieved by overexpressing the mutated feedback-resistant ARO4 K229L and ARO7 G141S , and a 3.61-fold improvement of p -coumaric acid production was obtained. Finally, formation of byproducts was decreased by deleting pyruvate decarboxylase gene PDC5 and phenylpyruvate decarboxylase gene ARO10 , and p -coumaric acid production was increased 2.52-fold. The best producer—when TAL1 , ENO2 , ARO1 , ARO4 K229L , ARO7 G141S , and TAL were overexpressed, and PDC5 and ARO10 were deleted—increased p -coumaric acid production by 14.08-fold (from 1.4 to 19.71 mg L −1 ). Our study provided a valuable insight into the optimization of l -tyrosine metabolic pathway.