Anaerobic biodegradation of spiramycin I and characterization of its new metabolites.

Activated sludge was used to treat the wastewater containing spiramycin I. Three new metabolites were isolated and identified, which produced by oxidation of C6-aldehyde, hydrolysis of C5-mycaminose-mycarose and macrolactone ring-open reaction of spiramycin I in anaerobic digestion. And their antimicrobial activities were inactivated. Our results indicated that anaerobic biodegradation metabolites of spiramycin I could not induce bacterial resistance in environment.