•We develop a novel process for erythromycin A separation from fermentation broth.•Pore diffusion limits the rate of fixed-bed adsorption of erythromycin onto resins.•Erythromycin recovery efficiency from filtrated broth into butyl acetate is over 96%.•Selectivity of Erythromycin A over Erythromycin C is 2.2 in aqueous crystallization.This work developed a novel process for erythromycin (EM) separation from fermentation broth, in which fixed-bed adsorption onto macroporous resins and aqueous crystallization were employed, aiming at efficient recovery of EM and effective removal of erythromycin C (EC) which is an analogue of desired erythromycin A (EA). Breakthrough curves of fixed-bed adsorption of EM were investigated, and the experimental data were correlated with Adams–Bohart model. The results showed that pore diffusion was the rate-limiting step of the adsorption, and the adsorption rate constant would decrease as inlet EM concentration increases. Through adsorption and subsequent desorption by butyl acetate (BA), more than 96% of EM could be recovered from filtrated fermentation broth into BA elution, where EM concentration was more than 65 mg/ml. EM in the BA elution was then transferred into KH2PO4–K2HPO4 buffer solution (pH 7.0) through evaporating azeotrope of BA and water. An aqueous crystallization in this buffer solution was then performed to remove EC. The effects of pH and temperature on this crystallization were studied. The results showed that, with the increase of pH from 9.0 to 10.0 or temperature from 35 °C to 55 °C, the crystallization yield of EA increased while that of EC increased first and then decreased. At pH 9.8 and temperature 50 °C, crystallization yields of EA and EC were 92.3% and 41.9%, respectively, thus the ratio of EA to EC in the product was increased 2.2 times.

(Liquid–liquid) equilibrium (LLE) data of the solubility curves and tie-line compositions have been determined for mixtures of (water + 3-hydroxy-2-butanone + ethyl ethanoate) at 298.15 K, 308.15 K and 318.15 K and 101.3 kPa. Distribution coefficients and separation factors have been evaluated for the immiscibility region. The reliability of the experimental tie-lines has been confirmed by using Othmer–Tobias correlation. The LLE data of the ternary systems have been predicted by UNIFAC method.Highlights► We examined LLE data of water + 3-hydroxy-2-butanone + ethyl ethanoate. ► Distribution coefficients and separation factors have been evaluated. ► We confirmed the reliability of experimental tie-lines. ► The LLE data of the ternary systems have been predicted by UNIFAC methods.

Liquid−liquid equilibrium (LLE) data of the solubility curves and tie-line compositions have been determined for mixtures of (water + 3-hydroxy-2-butanone +1-butanol) at 298.15 K, 308.15 K, and 318.15 K and 101.3 kPa. Distribution coefficients and separation factors have been evaluated for the immiscibility region. The reliability of the experimental tie-lines has been confirmed by using Othmer−Tobias correlation. The LLE data of the ternary systems have been predicted by the UNIFAC method.

Liquid−liquid equilibrium (LLE) data of the solubility curves and tie-line compositions have been determined for mixtures of (water + 3-hydroxy-2-butanone + butyl ethanoate) at (298.15, 308.15, and 318.15) K and 101.3 kPa. Distribution coefficients and separation factors have been evaluated for the immiscibility region. The reliability of the experimental tie-lines has been confirmed by using the Othmer−Tobias correlation. The LLE data of the ternary systems have been predicted by UNIFAC methods.

•We develop a novel process for erythromycin A separation from fermentation broth.•Pore diffusion limits the rate of fixed-bed adsorption of erythromycin onto resins.•Erythromycin recovery efficiency from filtrated broth into butyl acetate is over 96%.•Selectivity of Erythromycin A over Erythromycin C is 2.2 in aqueous crystallization.This work developed a novel process for erythromycin (EM) separation from fermentation broth, in which fixed-bed adsorption onto macroporous resins and aqueous crystallization were employed, aiming at efficient recovery of EM and effective removal of erythromycin C (EC) which is an analogue of desired erythromycin A (EA). Breakthrough curves of fixed-bed adsorption of EM were investigated, and the experimental data were correlated with Adams–Bohart model. The results showed that pore diffusion was the rate-limiting step of the adsorption, and the adsorption rate constant would decrease as inlet EM concentration increases. Through adsorption and subsequent desorption by butyl acetate (BA), more than 96% of EM could be recovered from filtrated fermentation broth into BA elution, where EM concentration was more than 65 mg/ml. EM in the BA elution was then transferred into KH2PO4–K2HPO4 buffer solution (pH 7.0) through evaporating azeotrope of BA and water. An aqueous crystallization in this buffer solution was then performed to remove EC. The effects of pH and temperature on this crystallization were studied. The results showed that, with the increase of pH from 9.0 to 10.0 or temperature from 35 °C to 55 °C, the crystallization yield of EA increased while that of EC increased first and then decreased. At pH 9.8 and temperature 50 °C, crystallization yields of EA and EC were 92.3% and 41.9%, respectively, thus the ratio of EA to EC in the product was increased 2.2 times.