9-27: Efficient production of 1,3-propanedion from crude glycerol by constitutive expression of 1,3-propanediol oxidoreductase gene in engineered Klebsiella penumoniae

Klebsiella pneumoniae is one of the well-known microorganisms, which produce 1,3-propanediol (1,3-PD) from glycerol. In this study, we developed an efficient process for 1,3-propanediol (1,3-PD) production from glycerol by genetic engineering of K. pneumoniae AK mutant strains, in which by-products formation was eliminated but IPTG induction was necessary for maximal production of 1,3-PD. A series of recombinant strain was designed to constitutively express dhaB and/or dhaT gene using bacteriophage T5 PDE20 and rho-independent transcription termination signal of Rahnella aquatilis levansurcrase gene. Among them, AK/pConT expressing dhaT alone was the most proper for 1,3-PD production. Fed-batch fermentation showed efficient production of 1,3-PD from both pure or crude glycerol without by-products formation. Further engineering to enhance production level would provide an economical biological process for 1,3-PD production.