Metabolism of the veterinary fluoroquinolone sarafloxacin by the fungus Mucor ramannianus

To investigate the microbial biotransformation of veterinary fluoroquinolones, Mucor ramannianus was grown in sucrose/peptone broth with sarafloxacin for 18 days. Cultures were extracted with ethyl acetate and extracts were analyzed by liquid chromatography. The two metabolites (26% and 15% of the A(280), respectively) were identified by mass and H-1 nuclear magnetic resonance spectra as N-acetylsarafloxacin and desethylene-N-acetylsarafloxacin, The biological formation of desethylene-N-acetylsarafloxacin has not been previously observed.