Study On The Production Of 1, 3-Propanediol By Fermentation

The thesis focuses on the selection of culture strain and the optimization of fermentation pathway in the production of 1,3-propanediol via microbial fermentation with glycerol. A fermentation control strategy with high production and efficiency has been obtained。A kind of ideal initial strain which had been mutagenized by ultraviolet light was used. After selection by coupling aerobic with and anaerobic culture, the mutagenized new strain can tolerate high concentrations of substrate and product,and the growth period and production period are shorten greatly.Based on the fedbatch strategy coupling the feeding of glycerol to pH control, the fermentation process was optimized in 15L fermentor anaerobic condition. The effect of auxiliary metabolic intermediate addition on the fermentative efficiency was investigated based on analysis of cell metabolism. The fermentative efficiency increased with additive organic acid such as Fumarate. In addition, effect of alcohol concentration on the fermentative production by Klebsiella pneumoniae was studied regarding to the characteristic of the specific cultivation condition, feasible ethanol-based fermentative manipulation strategy was established.Under these optimized conditions, accumulated concentration of 1,3-propanediol in fermentation broth reached to 80g/L, and mole conversion ratio of 1,3-propanediol based on glycerol consumption increases 65% than that of other feeding stratedies. The result provides a solid foundation for the industrialization of 1, 3-propanediol microbial fermentative production.