Fig. 3

De novo synthesis of vanillin using 3DSD-mediated pathway in S. cerevisiae. a Representative HPLC results showing vanillin levels in different strains and product distribution profile. Plasmid pRS423-AroZ/OMT and pRS425-CAR/PPTase were transformed into strain JS-CR(2 M) and JS-MARE3, respectively. Peak 1, protocatechuic alcohol; peak 2, vanillyl alcohol; peak 3, PCAL; peak 4, vanillin. The relevant standard curves are shown in Additional file 1: Figure S3. b The vanillin and PCA levels in strains with chromosomal 3DSD-mediated pathway. 3DSD encoded by AroZ from P. anserina and AsbF from B. cereus. c Schematic illustration of different strategies in improving the NADPH supply. d The vanillin and PCA levels in strains with engineered NADPH metabolism. e The vanillin and PCA levels in strains with engineered SAM cycle. Cells were grown in SC medium with 2% glucose, and samples were measured after 120 h of cultivation. All experiments were performed in triplicate and the data represent the mean value with standard deviation. Statistical analysis was carried out by using two-tailed unpaired Student’s t-test (*P < 0.05, **P < 0.01, ***P < 0.001)