Study Of Erythromycin Separation And Purification Process Using Resin Adsorption-Aqueous Crystallization Method

Erythromycin is an important kind of macrolide antibiotics, which is obtained from microbial fermentation in industry. The downstream separation and purification process is the key to production of erythromycin. Existing erythromycin separation processes are yet unable to recover principal product, erythromycin A, with high yield and remove the main byproduct, erythromycin C, at the same time. For this reason, this article developed a new erythromycin recovery process, which employs macroporous resin HZ816fixed-bed to adsorb erythromycin from fermentation liquid filtrated by50nm ceramic membrane, uses butyl acetate to desorb erythromycin from resin after washing resin with alkali buffer solution, then transfers erythromycin to phosphate buffer solution by carrying out heterogeneous azeotropic distillation of butyl acetate and water after adding immiscible phosphate buffer solution to erythromycin butyl acetate solution, and then crystalizes erythromycin by adding alkali to this phosphate buffer solution to increase pH.It turned out that:(1) Adams-Bohart adsorption model could fit erythromycin adsorption onto resin fixed-bed. Adsorption breakthrough loss was the function of adsorption amount, feeding flow velocity and feeding erythromycin concentration. When the adsorption amount was60%of the saturated amount, the adsorption yield could be98%at appropriate feeding flow velocity for different feeding erythromycin concentrations.(2) Protonized erythromycin could be converted to erythromycin alkali by washing resin with alkali buffer solution, thus the erythromycin desorption rate and yield increased and the consumption of desorbing agent, butyl acetate, decreased. Ammonia-ammonium chloride solution was a suitable choice for this process. After washing, desorption was carried out by butyl acetate at feeding flow rate of0.5fixed-bed volume per hour, and the yield of desorbed erythromycin in the first1.2fix-bed volume butyl acetate elution could be98%. The erythromycin concentration in butyl acetate elution was about61.5mg/ml.(3) Erythromycin could be transferred into aqueous solution after azeotropic distillation of butyl acetate and water and the yield could be96%. Then,4%ammonia water was added into the erythromycin aqueous solution until pH was9.6-9.8at temperature of50-55℃. The crystallization yield of erythromycin A could be96%while that of erythromycin C was only about50%.A whole erythromycin separation and purification process which consists of erythromycin adsorption, desorption and aqueous crystallization was established. It can recover erythromycin with yield of erythromycin A of89%and erythromycin C of46%, therefore can obtain high quality erythromycin from fermentation filtrate.