The Separation Of1,3-Prapanediol From Medium

1,3-prapanediol is an important chemical which attacts intrests recently. The production of1,3-prapanediol by microbial fermentation using the renewable material was regarded as an important method. The current methods for the separation of1,3-prapanediol include reactive-extraction, the adsorption using resin and zeolite, distillation and so on. In our paper, we tried to use zeolite adsorption and distillation for separation1,3-prapanediol.Comparing some zeolites, the FX-Ⅱ-type zeolite was used whose hydrophobicity and heat resistance is propitious to adsorb non-ionic organic compound in water. The saturation adsorption capacity for1,3-propanediol in single component solution was121.1mg/g. The adsorption capacity for1,3-propanediol was102.5mg/g in a neutral solution. With using50%ethanol, desorption yield of1,3-propanediol is86%. The selectivity of1,3-propanediol and glycerol using FX-Ⅱ-type zeolite is better. Comparing with the molar concentration ratio between1,3-propanediol and glycerol, the desorption result was127, and the ratio in raw fermentation was5. The dynamic adsorption of1,3-propanediol was67.4mg/g, and the desorption ratio for1,3-propanediol is83.7%. the molar concentration ratio of1,3-propanediol to glycerol in dynamic desorption was55.The separation of1,3-propanediol from fermerntation broth was influenced by the concentration of glycerol. In our paper, removing residual glycerol in flocculated fermentation broth by immobilized Klebsiela pneumoniae with Na-alginate bead was investigated. Under the optimal conditions which were that the ratio of biomass to Na-alginate was1:10, the concentration of Na-alginate solution was3%, the concentration of CaCl2solution was4%and the time of immobilization was24h, the residual glycerol was reduced by91%after16h. The glycerol concentration was1.2g/L. The immobilization cell can be used for three times.The distillation is a conventional method for separating the compound which has different boiling points. A techical route was conformed which included flocculation, ultra filtration, adjusting pH by Ca(OH)2, concentration and decompression distillation or molecule distillation. Through flocculation and ultra filtration, the thalli was removed mostly, and the protein was removed by88.6%. After concentration, the ratio of removal salt was60%. The fermentation liquor after concentration was separated by decompression distillation and molecule distillation. The results separated by decompression distillation showed that the 1,3-propanediol purity was97.5%and the recovery was51.1%between140～165℃. The result separated by molecule distillation showed that the1,3-propanediol purity was97.6%and the recovery was26%using the molecule distillation equipment which vaporing area was0.1m2.