Fig. 6

Co-expression of key genes ribB, ribC, NfStyA2B, and CAT by different promoter combinations. a 9-OHAD product and cell growth. b Intracellular FAD level, c NAD+ level, and ratio of NADH/NAD+ in engineered strains with combinations of different promoters and genes. All engineered strains were cultivated in fermentation medium containing 4 g/L phytosterols at 30 °C for 144 h. The data represent the mean ± standard deviation of three measurements