Optimization of the l-tyrosine metabolic pathway in by analyzing -coumaric acid production.

In this study, we applied a series of genetic modifications to wild-type strain BY4741 to address the bottlenecks in the l-tyrosine pathway. A tyrosine ammonia-lyase (TAL) gene from , which can catalyze conversion of l-tyrosine into -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 , enolase II gene , and pentafunctional enzyme gene resulting in a 1.55-fold increase in -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 and , and a 3.61-fold improvement of -coumaric acid production was obtained. Finally, formation of byproducts was decreased by deleting pyruvate decarboxylase gene and phenylpyruvate decarboxylase gene , and -coumaric acid production was increased 2.52-fold. The best producer-when , , , , , and were overexpressed, and and were deleted-increased -coumaric acid production by 14.08-fold (from 1.4 to 19.71 mg L). Our study provided a valuable insight into the optimization of l-tyrosine metabolic pathway.