11-32: Optimization of culture conditions to increase 1,3-propanediol production from glycerol using engineered Klebsiella pneumoniae

1,3-propanediol (1,3-PD) is of commercial attention as an important monomer to synthesize a new type of polyester, polytrimethylene terephthalate (PTT) which has excellent properties in textile and fiber industries.Recently we engineered mutant strains of K. pneumoniae to eliminate the formation of by-products hindering the downstream process, typically 2,3-butanediol, during the production of 1,3-propanediol (1,3-PD) from glycerol by inactivating the oxidative branch of the glycerol metabolic pathway. Although the by-product formation was successfully eliminated, production yield and productivity of 1,3-PD was severely diminished in the mutant strains. This study presents optimization of culture conditions to improve the 1,3-PD production using the recombinant strain defective of the glycerol oxidative pathway eliminating by-product formation. The fed-batch fermentation by K. pneumoniae AK-VOT from glycerol with starch was achieved leading to 28.1 g/L of 1,3-PD with a yield of 0.64 mol/mol and productivity of 0.51 g/Lh.