Fig. 2

Biosynthetic pathway of scopoletin from glucose or lignin-derived aromatics. The compounds in the purple box are the two major monomers derived from lignin after pretreatment. The compound in the orange box is scopoletin, which is the target product produced by the microbial cell factory in this paper. TAL: tyrosine ammonia lyase; PAL: phenylalanine ammonia lyase; 4CL: 4-coumarate CoA ligase; FCS: feruloyl-CoA synthase; C4H: cinnamate-4-hydroxylase; HHA: 4-hydroxyphenylacetic acid 3-hydroxylase A; C3H: coumarate-3-hydroxylase; F6’H: feruloyl-CoA 6'-hydroxylase; C2'H: coumaroyl CoA 2'-hydroxylase; COSY: coumarin synthase; S8H: scopoletin 8-hydroxylase; CCoAOMT: caffeoyl-CoA O-methyltransferase; CYP82C4: cytochrome P450 family B2 subfamily C polypeptide 4 enzyme. Three consecutive arrows indicate multiple biosynthetic steps