Study On Clostridia Pasteuianu Mutation For The High Production Of 1, 3-Propanediol

1,3-propanediol(1,3-PD)is a multi-purpose intermediate and has a wide range of potential use, particularly as a monomer for the production of biodegradable polymers-PTT fiber. Compared with chemical synthesis, microbial fermentation processes to 1,3-PD have many obvious advantages, the environmental friendship and price advantage make it more promising, and become the focuses of reach.Based on ion ray and ultraviolet light mutation methods, the product tolerance capability, the flat-panel screening technique was established, in order to increase the conversion ability of glycerol into 1,3-propanediol by Clostridia pasteuianu. The activities of glycerol dehydratase(GDHt) and 1,3-propanediol oxidoreductase(PDOR) are also studied.Using this approach, two excellent mutants tolerating 1,3-propanediol with high concentration are achieved. Compared to original strain, the 1,3-propanediol production capability of these two mutants was increased by 43% and 40%, increased to 66.84g/L and 65.62g/L.And meanwhile ferment conditions under which Clostridia pasteuianul fermenting Glycerol yield l,3-propanediol were also researched by analysing the influence such as pH, fermentation time, inoculation volume, Mg, Fe, and Trace Elements exert on the production process. The result illustrated that the growth speed of Clostridia pasteuianul was postive related to the pH whereas the final concentration of 1,3-propanediol was negative related with the pH. To obtain a high production of 1,3-propanediol, the fermentation time must persist 24 hours and the inoculation volume must be kept at 6%. Mg, Fe and Trace Elements could be added in the media , whose volume should not be too high to keep 1,3-propanediol as the main ingrediant, and whose volume should not be too low to avoid preventing the growth of Clostridia pasteuianul. Finally, after a series researches, the optimizing media selected for fermentation is that Glycerol 40.0 g/L,KH₂PO₄ 0.5 g/L,K₂HPO₄ 1.0 g/L,(NH₄)₂SO₄ 3.0 g/L,CaCO₃ 2.0 g/L,FeSO₄0.01 g/L,MgSO₄·7H₂O 0.2 g/L, Yeast extract 1.0 g/L,CaCl₂·2H₂O 0.02 g/L,trace elements 2mL /L,pH6.5.