The Research And Development Of Ramoplanin

Ramoplanin is one of the compounds under clinical trial, which is effective to MRSA (Methicillin resistant Staphylococcus aureus) and VRE (Vancomycin resistant Enterococcus).A strain (Actinoplanes sp.), ATCC33076, was used in this study. After natural isolation, the fermentation technology of strain ATCC33076 was further improved: single factor experiments showed that starch and glucose were the best carbon source, soybean powder was the best nitrogen source. Many conditions of ramoplanin fermentation were investigated including culture volume, inoculation ratio, initial pH of fermentation medium and cultural temperature. And more addition of precursor L-Leu was also investigated. The results showed that a 750ml shake flask containing 100ml medium was suitable, the best inoculation ratio was 6%, the best initial pH of fermentation medium was 7.0, suitable cultural temperature was 25℃ .On the other hand, feeding of L-leucine into the broth before cultivation increased the fermentation potency. Compared with that of basal condition without any addition of precursor, the productivity was increased by 150%.The broth was obtained in a large volume, using methnol extraction, silica gel column chromatography and reverse chromatography, compounds SIPI411040801, SIPI411040802 and SIPI411040803 were isolated from the broth; by the analyses of their physico-chemical properties, MS, UV and IR spectra data, their structures were identical with Ramoplanin A₁, Ramoplanin A₂ and A₃, respectively.