1, 3-propanediol Production From Glycerol By Klebsiella Pneumoniae

The thesis focuses on and the optimization of fermentation pathway in the production of 1,3-propanediol from glycerol using Klebsiella pneumoniae1.1736 under microaerobic conditions. A fermentation control strategy with high production and efficiency has been obtained.The experiments were carried out under shaking flasks using analytically pure glycerol with only gauze and without pumping nitrogen. Basic fermentation conditions were investigated,including inoculation volume, temperature, initial concentration of glycerol, initial pH, nitrogen sources, glucose and citric acid. Under micriaerobic condition with the optimized medium and culture parameters: initial glycerol concentration 20g/L, Yeast extract powder1g/L, glucose 6g/L, inoculation volume 10%, initial pH 6.7and 37℃; the molar yield of PDO and the utility of glycerol reached 57.03% and 91.65%, respectively. With citric acid added in the fermentation system, the molar yield of PDO was increasing a little.By utilizing the optimized medium and culture conditions in 2L Fermentor, the fermentation conditions of Klebsiella pneumoniae1.1736 were investigated, including pH,different aeration conditons in bath fermentation and different glycerol feed concentration in fed-bath fermentation. the optimized fermentation pathway was pH 7.5, 0.2 vvm air and two-stage of glycerol feed concentration:8~12h, 3.0g/L/h, 12~40h, 4.5g/L/h.the maximum biomass concentration OD650 was 7.26, the concentration of 1,3- propanediol was 58.85 g/L. With CaCO3 added in the fermentation system, the yield of PDO was not Significantly improving.By utilizing the optimized culture conditions in 2L Fermentor with crude glycerol, the fermentation conditions of Klebsiella pneumoniae 1.1736 were investigated. The concentration of 1,3- propanediol with CaCO3 added were moer 9.5% than without CaCO3 in bath fermentation. the maximum biomass and 1,3- propanediol concentration was 7.26 respectively, by pH 7.5 control with CaO solution in fed-bath fermentation.The experiments focuses on the fermentation of 1,3-propanediol to Novozyme 435with pure glycerol by pH 7.5 control with NaOH solution in fed-bath fermentation. In water phase Novozyme 435 was higher catalytic activity to 1, 3 - propanediol than pure glycerol. the concentration of 1, 3-propanediol was 61.42g/L with Novozyme 435 in fed-bath fermentation of 2L fermentor. the concentration of 1, 3-propanediol with Novozyme 435 was higher 4.5% than without Novozyme 435.