Fig. 1
Metabolic pathways associated with terpenoid biosynthesis in B. subtilis and engineering strategies for the production of yellow C30 carotenoids 4,4’-diaponeurosporene and 4,4’-diapolycopene (C30 pathway). Foreign genes are marked in red. Yellow arrows outlined in black indicate the reactions reinforced by chromosomic overexpression of the fpps gene (farnesyl diphosphate synthase) from B. megaterium DSM 319, crtM (squalene desaturase) and crtN (dehydrosqualene desaturase or diapophytoene desaturase) genes from S. aureus, and deletion of the yisP (farnesyl diphosphate phosphatase) gene, yielding the C30 carotenoid pigments 4,4’-diaponeurosporene and 4,4’-diapolycopene. Enzymes in the MEP (Methylerythritol 4-phosphate) pathway: 1-deoxy-D-xylulose-5-phosphate synthase (Dxs); 1-deoxy-D-xylulose-5-phosphate reductoisomerase or 2-C-methyl-D-erythritol 4-phosphate synthase (Dxr, also known as IspC); 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase (IspD); 4-(cytidine 5′-diphospho)-2-C-methyl-D-erythritol kinase (IspE); 2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase (IspF); (E)-4- hydroxy-3-methylbut-2-enyl-diphosphate synthase (IspG); 4-hydroxy-3- methylbut-2-enyl diphosphate reductase (IspH); and isopentenyl-diphosphate delta-isomerase (Idi). Geranyltransferase (IspA, also known as YqiD) refers to the B. subtilis gene responsible for the supply of GPP (geranyl diphosphate) and FPP (farnesyl diphosphate) precursors