[Isolation, identification and biodegradation characterization of a novel monensin-degrading bacterial strain]

Biodegradation of antibiotic pollutants by microorganisms has received widespread attention, to which the identification of microorganisms capable of efficiently degrading antibiotics is a key. In this study, a strain DM-1 with high degradation capability was successfully isolated from monensin-contaminated chicken manure by using monensin as the sole carbon source. The strain was further identified basing on morphological, physiological and biochemical characteristics and 16S rRNA gene sequence-based phylogenetic analysis. The degradation efficiency of DM-1 for monensin was determined by HPLC post-column derivatization, and then the degradation conditions of DM-1 were optimized. DM-1 was identified as a strain of Acinetobacter and named as Acinetobacter baumannii DM-1. The optimal conditions for monensin degradation by strain DM-1 were pH 7.0, 30 ℃, and initial monensin concentration of 50 mg/L. The strain DM-1 degraded more than 87.51% of monensin at an initial concentration of 10 mg/L in 28 days, while only a slight decrease in monensin concentration was observed in the control without monensin-degrading strain. This study indicates that the strain DM-1 has a promising application prospect in the bioremediation of monensin-contaminated environment.