Study On Crystallization Of Kelimycin

Kelimycin, a group of 4"-o-acylated spiramycins with 4"-o-isovalerylspiramycins I, II, III as main components, is produced by genetic engineering bacteria. Its separation and purification from fermentation broth and quality control is difficult due to the low content and proportion of major components. Aqueous crystallization of Kelimycin was studied both theoretically and experimentally in this paper to improve product quality and yield, which was of great significance for industrial production of Kelimycin.Processes of separation and purification involved in this paper are as follow:micro-filtration, ion-exchange resin discoloration, macro porous resin absorption, petroleum ether desorption, phosphate solution extraction, crystallization, drying. Extraction, the preparation process for crystallization, transfers and concentrates Kelimycin from organic phase (Petroleum ether) to aqueous phase (0.7%NaH2PO4-H3PO4 buffer solution). The extraction process and crystallization process were studied in detail in this paper.1. The solubility of Kelimycin in phosphate solution at different temperature, pH and concentration of NaH2PO4 and petroleum ether were determined. Mathematical correlation equations were obtained by curve fitting. The experimental results demonstrated that all these three factors had significant effect on the solubility of Kelimycin. The dissolution process had components selectivity.2. The effect of stirring speed, pH and concentration of NaH2PO4 on extraction rate was studied from the aspect of kinetics. Extraction kinetic models were developed on the basis of experimental data and kinetic constants were calculated.The effect of temperature, pH and the concentration of NaH2PO4on the extraction was studied from the aspect of thermodynamics. The process conditions were optimized. The extraction distribution coefficient mathematical model was derived and established based on experimental data.3. The effect of temperature and crystallization end pH on crystallization yield, percentage of components, crystalline grain size was studied in detail. Aqueous warming crystallization was compared with reactive crystallization. Optimum crystallization conditions were determined.So far, no similar research reports were found in literatures.