Biosynthesis of 1,3-Propanediol via a New Pathway from Glucose in Escherichia coli

1,3-Propanediol (1,3-PDO), an important dihydric alcohol,is widelyused in textiles, resins, and pharmaceuticals. More importantly, itcan be used as a monomer in the synthesis of polytrimethylene terephthalate(PTT). In this study, a new biosynthetic pathway is proposed to produce1,3-PDO using glucose as a substrate and l-aspartate as aprecursor without the addition of expensive vitamin B-12. We introduced a 3-HP synthesis module derived from l-aspartateand a 1,3-PDO synthesis module to achieve the de novo biosynthesis.The following strategies were then pursued that included screeningkey enzymes, optimizing the transcription and translation levels,enhancing the precursor supply of l-aspartate and oxaloacetate,weakening the tricarboxylic acid (TCA) cycle, and blocking competitivepathways. We also used transcriptomic methods to analyze the differentgene expression levels. Finally, an engineered Escherichiacoli strain produced 6.41 g/L 1,3-PDO with a yieldof 0.51 mol/mol glucose in a shake flask and 11.21 g/L in fed-batchfermentation. This study provides a new pathway for production of1,3-PDO.