Efficient production of 1,3-propanediol from glycerol upon constitutive expression of the 1,3-propanediol oxidoreductase gene in engineered Klebsiella pneumoniae with elimination of by-product formation

In the present study, we developed an efficient method of 1,3-propanediol (1,3-PD) production from glycerol by genetic engineering of Klebsiella pneumoniae AK mutant strains. The proposed approach eliminated by-product formation and IPTG induction resulted in maximal production of 1,3-PD. A series of recombinant strains was designed to constitutively express the dhaB and/or dhaT genes, using the bacteriophage T5 P-DE20 promoter and the rho-independent transcription termination signal of the Rahnella aquatilis levansucrase gene. Among these strains, AK/pConT expressing dhaT alone gave the highest yield of 1,3-PD. Fed-batch fermentation resulted in efficient production of 1,3-PD from either pure or crude glycerol, without by-product formation.