Fermentative Production Of 1, 3-propanediol From Glycerol By Clostridium Butyricum

Propanediol(1,3-PDO) is an important materials in chemical industries, Which is widely used not only as solvent,cryoprotectcont and lubricant, but also as a potential intermediate in finechemistry, cosmetic and pharmacy industries. Up todays, chemical industrial routes for the production of 1,3-PDO has been reported though the hydration of acrolein or the hydroformylation of ethylene. Chemical routes are expensive and pollute the environment. Because of the difficulties in the materials supplement and equipment, the chemical routes hasn't be industrialized in china. The productions of 1,3-PDO by microbes are increasing interested due to the environment reasons, industrial safety and renewable sources. The present studies were designed to optimize the cultures of producing 1,3-PDO by Clostridium butyricum and analysis the effects on fermentation in order to produce 1,3-PDO effectively. The property, structure, applications, the current production situation of 1,3-PDO and the fermentation processes of glycerol producing 1,3-PDO by C.butyricum are introduced in this dissertation. The optimal conditions of 1,3-PDO fermentation using shaking-flask were investigated. The effects of temperature, pH, and agitation rate on fermentation were studied. The effects of medium composition on the production of 1,3-PDO were also studied in shaking-flask culture. Under optimized conditions, 41.3g/L of 1,3-PDO was produced from 6%glycerol, with the mass yield of 68.8%. In the experiment of amplification, the parameters of aeration of stirring in the 3L fermenter were studied. It is an attempt to set up a foundation of industry production of 1,3-PDO. Stoichiometric analysis is applied to calculate the theoretical yields of glycerol fermentation by C.butyricum under different conditions. The acetic acid pathway for the production of 1,3-PDO is more efficient than the butyrate pathway. The theoretical maximum yield of 1,3-PDO (0.72mol/mol glycerol), is calculated for the fermentation without hydrogen and butyric acid formation. The kinetic equation of culture in the batch has been obtained. And according to this,the kinetic model combined with material balance of fermentation process is established to set up a theoretical foundation for increasing the yield of 1,3-PDO.