Production Of Ferulic Acid And Coniferyl Alcohol In Engineered Escherichia Coli

L-tyrosine is one of the aromatic amino acids,which can be used as nutritional additive and raw material for the preparation of some important pharmaceutical and chemical products.It has been widely used in the fields of medicine,food,feed and chemical industry.At the same time,it is also an important platform compound,for many aromatic compounds with high added value can be biosynthesized from L-tyrosine.Starting from Escherichia coli BL21（DE3）strain,a tyrosine-producing chassis strain was constructed by metabolic engineering strategy.Hydroxycinnamic acid modules and coniferyl alcohol module were constructed and optimized to realize the de novo biosynthesis of important tyrosine derivatives in Escherichia coli.First,the biosynthesis pathway of tyrosine in E.coli strain was modified.On the one hand,the feedback suppressor gene tyr R and phenylalanine competition pathway gene phe A were knocked out.On the other hand,tyrosine module containing aro G^fbr,tyr A^fbr and aro E genes were constructed.In addition,the global regulatory gene met J in the methyl donor biosynthesis pathway was knocked out to increase the supply of methyl donor to achieve the biosynthesis of different tyrosine derivatives.After 24 h,the titer of L-tyrosine reached 713.52 mg/L,which provided a chassis for efficient downstream biosynthesis of tyrosine derivatives.After studying the effects of his tag on exogenous genes,the biosynthesis modules of coumaric acid,caffeic acid and ferulic acid were reconstructed,and the supply of methyl donors in the biosynthesis of ferulic acid was optimized.The adaptability of the bipsynthesis module to tyrosine chassis strains was studied.The yield of coumaric acid,caffeic acid and ferulic acid reached 424.24 mg/L,147.22 mg/L and 50.97 mg/L after24 h,respectively.The coniferyl alcohol module was modified and optimized.The combination of coniferyl alcohol module with ferulic acid module and the suitability of chassis strain were studied.The fermentation process and medium conditions were optimized.The titer of coniferyl alcohol reached 166.24 mg/L from simple glucose in E.coli.In this paper,a tyrosine-producing chassis strain was constructed by synthetic biology and metabolic engineering strategy,and the biosynthesis modules of coumaric acid,caffeic acid,ferulic acid and coniferyl alcohol were constructed and optimized,which provided new ideas for the biosynthesis of other important L-tyrosine derivatives in Escherichia coli.