Study On Separation Process Of Echinocandin B From Aspergilus Nidulans Zjb09223 Broth

Echinocandin B is a kind of microbial secondary metabolites produced by Aspergillus nidulans.It is the precursor compounds which can synthesize anidulafungin.Now there are some problems on the study about separation of ECB.It includes heavy use of organic solvent complex operation process,lower yield and purity.The main purpose of this thesis is to systematically analyze the static adsorption properties of Echinocandin B on macroporous resin,fixed-bed mass transfer behavior and explore a new process that Echinocandin B is separated from the fermentation broth of A.nidulans ZJB09223.The results of the study were as follows.The adsorption property of dozens of macroporous resin to ECB was studied.It was showed that macroporous resin HP20 had maximum adsorption capacity and desorption rate.Then the static adsorption properties on HP20 macroporous resin were studied.The isotherms data were well fitted to Langmuir model which suggested that it was a physical adsorption and spontaneous exothermic process.The data obtained by adsorption kinetics experiments was fitted via four kinds of dynamics model.The second-order kinetic model had a higher correlation co-efficiency.The value fitted with second-order kinetic model was nearest to the experimental value.The adsorption rate can be promoted by increasing the speed of rotary shaker and initial concentration of ECB.Breakthrough curves through the fixed bed experiments showed that:with the increasing initial concentration of ECB,breakthrough point and saturation point appeared in advnce and adsorption equilibrium time was reduced.The penetrate,saturation volume and penetrate,saturation adsorption capacity were decreased with the increasing flow rate.With the increasing of height-to-diameter ratio of the bed,penetrate,saturation volume and penetrate,saturation adsorption capacity of ECB were increased.The eluted curves was more symmetrical and the desorption rate was higher with 80%(v/v)ethanol eluting.The process on separating ECB from fermentation broth included organic solvent extraction,resin adsorption-desorption,decolouration and precipitation.The extraction process was as follows:extraction agent was ethanol,the solid-liquid ratio was 1:1.5,temperature was 35?,extracted times were 3,the extract yield of ECB can reach more than 90%.Using HP20 macroporous resin to adsorb ECB,then was desorbed with 80%(v/v)ethanol.The decoloring process was confirmed as followings:the adding amount of WD-6 resin was 4%(g/v).Shaking bath speed was 150 rpm.The decoloring temperature was 30 C.The decoloring time was 100 mins.Under this condition,the decolorization rate can reach 88.3%,the loss of rate was 4.8%.The concentration of ECB can be condensed to 25mg/ml.Then the precipitate can be obtained with diluting for 5 times.Under this process,the ECB recovery rate was about 68%and the purity of ECB was above 80%.