Bioconversion, purification and characterization of tylvalosin

Tylvalosin is a new macrolide antibiotic for veterinary use. The study reported in this paper dealt with the systematic bioconversion, purification and characterization of tylvalosin. In this work, tylvalosin was synthesized by a bioconversion using Streptomyces thermotolerans with tylosin as the substrate, in which the final yield was 8148 U mL −1 . Subsequently, the crude tylvalosin was obtained from an acid and alkali recrystallization of the fermentation broth. High-purity tylvalosin was subsequently obtained from silica gel column chromatography separation. In the advanced separation, silica gel was the separation medium and a mixture of ethyl acetate and petroleum ether (contained 0.1% triethylamine) was used as the eluent. The activity of the pure tylvalosin was 996 U mg −1 as determined by microbiological assay and the purity of the product was 96.0% as determined by high-performance liquid chromatography. The tylvalosin product was qualitative analysed using ultra performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry. The structure of the tylvalosin product was characterized using infrared spectroscopy and nuclear magnetic resonance analysis. The crystal structure of the tylvalosin was determined using by X-ray single crystal diffraction. In summary, this study established a complete method for the biotransformation, separation, purification and characterization of tylvalosin.