Biosynthesis Of 2,3-butanediol By Klebsiella Pneumonia ZH-1

2,3-butanediol?2,3-BD?is a valuable chemical fuel and liquid fuel which is wide range of applications such as chemical engineering,daily chemicals,food,medicine,and aerospace.This experiment is based on laboratory-preserved Klebsiella pneumonia ZH-1strains that have been separated from the sludge of Fenhe River.The 2,3-BD culture medium,the fermentation conditions,the byproducts of the metabolic process,and the process of extracting 2,3-BD were studied in order to increase the production of 2,3-BD by K.pneumonia ZH-1.The main results of this experiment are as follows:1.The effects of carbon sources,nitrogen sources,inorganic salts,and metal ions in the culture medium on fermentation production of 2,3-BD by K.pneumonia ZH-1 were investigated.On the basis of the above single-factor inquiry experiments,four factors that greatly influence the production of the target product 2,3-BD were selected to conduct an orthogonal test of four factors and three levels,and the best medium was finally determined?g/L?:glucose 60;yeast extract 10;KH₂PO₄ 4;K₂HPO₄ 24;?NH₄?₂SO₄ 2;sodium citrate 1;CuSO₄ 0.04;EDTA 0.05.2.Exploring the effects of nutrients:organic acids,alcohols,amino acids,and vitamins on fermentation production of 2,3-BD by K.pneumonia ZH-1,in which lactic acid and acetic acid produce 2,3-BD in the fermentation of K.pneumonia ZH-1.The effect of2,3-BD is relatively large;methanol has a greater influence on the fermentation of 2,3-BD;glycine,aspartate and valine have a greater influence on the metabolic production of 2,3-BD;in the medium,the addition of folic acid had the best effect on the production of 2,3-BD by K.pneumonia ZH-1.3.Based on the best medium formulation,the initial pH,temperature,dissolved oxygen?shaker speed and liquid volume?,the time of static culture after shaker culture and the inoculum amount were studied on K.pneumonia ZH-1 fermentation.The effect of producing 2,3-BD.Based on the above single factor experiments,several key factors such as pH,temperature,and shaker rotation speed were selected.Based on the Central-Composite Design-response surface optimization method,the production of 2,3-BD for K.pneumonia ZH-1 fermentation was designed.The optimum fermentation conditions model was determined to determine the optimal theoretical fermentation conditions:temperature 37°C,pH 7,shaker speed 140 r/min,at this time the yield of 2,3-BD can reach 22.04 g/L.The forecasted value increased by 2.32%.4.The effects of metabolic by-products ethanol,lactic acid,acetic acid and succinic acid on the production of 2,3-BD by K.pneumonia ZH-1 were investigated.From the results,it can be seen that when the ethanol concentration is 0-7 g/L,the yield of 2,3-BD first increases and then decreases,and the optimal concentration of ethanol is 3 g/L;when lactic acid and acetic acid are added,The trend of yield change of 2,3-BD was the same as that of ethanol.The optimal concentrations of lactic acid and acetic acid were 1.5 g/L and 2.5 g/L,respectively;succinic acid inhibited the growth of the strain and the production of 2,3-BD.5.Explore the effects of common liquid-liquid extraction and aqueous two-phase extraction on the purification of 2,3-BD.The extraction rate of 2,3-BD was higher when ethyl acetate was used as the extractant,using different extractants and two aqueous systems,respectively.A single factor study was carried out on the three extraction conditions:extraction time,extraction temperature and extraction times.Based on this,a Box-Behnken Design-response surface optimization method was used to design the optimal extraction conditions for 2,3-BD.The optimum theoretical extraction conditions were as follows:extraction time 2 h,extraction temperature 60°C,and extraction times 3.The extraction rate of 2,3-BD at this time could reach 77.28%,which was 2.61%higher than the predicted value.