Improvement of the riboflavin production by engineering the precursor biosynthesis pathways in Escherichia coli

大肠杆菌中核黄素的底物合成途径改造及生产（英文）

3,4-Dihydroxy-2-butanone 4-phosphate （DHBP） and GTP are the precursors for riboflavin biosynthesis. In this research, improving the precursor supply for riboflavin production was attempted by overexpressing ribB and engineering purine pathway in a riboflavin-producing Escherichia colt strain. Initially, ribB gene was overexpressed to increase the flux from ribulose 5-phosphate （Ru-5-P） to DHBP. Then ndk and grnk genes were overexpressed to enhance GTP supply. Subsequently, a R419L mutation was introduced into purA to reduce the flux from IMP to AMP. Finally, co-overexpression of mutant purF and prs genes further increased riboflavin production. The final strain RF18S produced 387.6 mg riboflavin · L-1 with a yield of 44.8 mg riboflavin per gram glucose in shake-flask fermentations. The final titer and yield were 72.2% and 55.6% higher than those of RF01S, respectively. It was concluded that simultaneously engineering the DHBP synthase and GTP biosynthetic pathway by rational metabolic engineering can efficiently boost riboflavin production in E. coll.

3,4-Dihydroxy-2-butanone 4-phosphate(DHBP) and GTP are the precursors for riboflavin biosynthesis.In this research,improving the precursor supply for riboflavin production was attempted by overexpressing ribB and engineering purine pathway in a riboflavin-producing Escherichia coli strain.Initially,ribB gene was overexpressed to increase the flux from ribulose 5-phosphate(Ru-5-P) to DHBP.Then ndk and gmk genes were overexpressed to enhance GTP supply.Subsequently,a R419 L mutation was introduced into purA to reduce the flux from IMP to AMP.Finally,co-overexpression of mutant purF and prs genes further increased riboflavin production.The final strain RF18 S produced 387.6 mg riboflavin ·L^(-1) with a yield of 44.8 mg riboflavin per gram glucose in shake-flask fermentations.The final titer and yield were 72.2%and 55.6%higher than those of RF01 S,respectively.It was concluded that simultaneously engineering the DHBP synthase and GTP biosynthetic pathway by rational metabolic engineering can efficiently boost riboflavin production in E.coli.