Fig. 2: Enzyme and pathway engineering for efficient production of 3-HP.

a Genes encoding of split MCR enzymes were either integrated in the chromosome or expressed using the plasmid system. b MCR-N domain and MCR-C*** domain co-expressed with the high copy plasmid could produce 4.12 g/L 3-HP. c Homologous modelling structure of the domains in malonate semialdehyde reductase and malonyl-CoA reductase from C. aurantiacus. d Swapping of native MCR domains with Ora1 and YdfG improved 3-HP production to 5.2 g/L and 5.3 g/L, respectively. e Carbon flux rewiring from fatty acids to 3-HP. f Downregulation of FAS1 combined with upregulation of POX2 and POX1 improved the production of 3-HP. g Nile red staining demonstrated that the size and the number of lipid droplets decreased in the fatty acid oxidation strain QLW36 compared with that of QLW26. (h) The fluorescence intensity of neutral lipids stained with Nile red in QLW26 and QLW36 was quantified in Relative Fluorescence Units (RFU). The RFU values were corrected by subtracting both the inherent autofluorescence of the samples and the fluorescence contributed by the solvent in the presence of Nile red (blank). Abbreviations were defined in Supplementary Data 5 and 6. The defined minimal medium with 10 mM NaHCO₃ was used for the 3-HP production. All data were presented as mean ± SD of biological triplicates. Significant comparisons of two groups were indicated in the graphs statistical analysis performed using a two-tailed unpaired Student’s t-test (*p < 0.05, **p < 0.01, ***p < 0.001). Source data are provided as a Source Data file.