Isolation and purification of novel antifungal antibiotic from streptomyces ahygroscopicus

A technically feasible purification process for a novel pyrimidine nucleoside antifungal antibiotic produced by a Streptomyces strain(Streptomyces ahygroscopicus ZJUIB001) was conducted.The centrifugated culture broth was extracted with chloroform and then with petroleum ether.The water phase solution was adjusted to pH=2 and further isolated by cation-exchange chromatography,which was followed by macroporous resin adsorption.Dowex 50 × 16 was screened as the most suitable cation-exchange resin for removing the impurity from the crude extract under the optimized operating conditions as follows: sample loading flow rate of 2 bed volume(BV) per hour and eluting flow rate of 1 BV per hour using 0.6 mol/L NH3·H2O as the mobile phase.Amberlite XAD7HP was selected as the most suitable macroporous adsorption resin for the further purification of the antibiotic.The optimized desorbing condition of macroporous resin adsorption chromatography was multi-step gradient elution with ethanol solutions of 10% and 70% volume fraction,respectively.Then the purified antifungal compound was subjected to high-performance liquid chromatographu(HPLC) system with a YMC-C18(5 μm,Φ4.6 mm×250 mm) column.The mobile phase was 0.01 mol/L ammonium acetate buffer(pH 4.3).The flow rate was 1 mL/min and the elution was detected at 220 nm.HPLC results show that the purified antibiotic compound has a purity of 93.0% with antifungal activity of 21 632 U/mg.