Optimization For1,3-propanediol Production By Fermentation

1,3-propanediol (1,3-PDO) is an important chemical material and can be used as monomer to produce polyesters, polyethers and polyurethanes. Its biosynthetic method arouses our more and more interests.Two main parts were investigated as follows:PartA The optimization for fermentation technology of1,3-propanediol production by wild-type Klebsiella pneumoniae.The concentration of substrate restraint was lowered through the optimization for the concentration of glycerol. The concentration of1,3-propanediol (62.03g·L-1), molar yield of glycerol(mol·mol-1) and the productivity (1.94g·(L·h)-1) were increased44.3%,4%and79.6%respectively, than the original method.Soybean powder which was a kind of Low-cost nitrogen was found to decreased the cost of the fermentation.A controlling method of media-metabolin online fedback was constituted for conquering the disadvantage of the delay and the blindness of feeding. The online controlling of the substrate(glucose and glycerol) without measuring the substrate concentration was realized by the feeding method which was based on the mathematic connection between the consumption of the substrate and the consumption of the media-metabolin. So the controlling method was simplified.PartB The elementary study for fermentation of the recombinant Klebsiella pneumoniae.The technology of the fermentation of the recombinant Klebsiella pneumoniae was studied. Though microaerobic fermentation, the molar yield was lower than anaerobic fermentation the concentration of1,3-propanediol and the productivity were increased.In order to improve the tolerance to product inhibition of recombinant Klebsiella pneumoniae so as to increase the yield of1,3-propanediol, UV/LiCl mutaiton associating with domestication was performed. The excellent mutant M-5, which could tolerate high1,3-propanediol concentration(95g·L-1) was obtained. The fed-batch fermentation fo1,3-propanediol by mutant M-5was studied. The1,3-propanediol concentration of mutant M-5was24%higher than that of parent strain, the acetate acid concentration increased while the ethanol concentration decreased.The30L fed-batch culture of recombinant Klebsiella pneumoniae under microaerobic condition was studied. The glucose was used for assiatant carbon source and the the glucose was fed in the beginning and the feeding process.The concentration of1,3-propanediol, molar yield and productivity were87.1g·L-1,0.65mol·mol-1and2.9g·(L·h)-1respectively, which were 40.4%,25%and49.5%higher than the wild-type Klebsiella pneunoniae. The concentration of1,3-propanediol, molar yield and productivity were83.8g·L-1,0.65mol·mol-1and2.79g·(L·h)-1respectively in150L fed-batch culture. The productivity was steady and made substaintial foundation for pilot-scale production and industrialisation.