Characterization of microbial degradation of oxytetracycline in river water and sediment using reversed phase high performance liquid chromatography

The fate of oxytetracycline (OTC) in river water and sediment and control experiments was investigated. A high-performance liquid chromatography (HPLC) separation and identification method was used to separate, identify and quantify OTC and its major degradation products. Minimum degradation of OTC was observed in control experiments. Non microbial degradation observed up to day 26 contributed slightly above 20% of the degradation in exposed distilled water experiment. Increase in degradation of OTC after day 26 for both the covered and exposed distilled water experiments were attributed to microbial degradation due to contamination through the openings left in the set ups. Microbial degradation was observed in the river water and sediment experiment and two major degradation products were identified: 4-epi-oxytetracycline (4-epi-OTC) and β-apo-oxytetracycline (β-apo-OTC). β-apo-OTC was found to be the most stable degradation product as compared to the other main degradation products 4-epi-oxytetracycline (4-epi-OTC) and α-apo-oxytetracycline, (α-apo-OTC). The present results have shown that microbial degradation plays a major role in the removal of OTC in natural environments.    Key words: Oxytetracycline, microbial degradation, rephrased phase HPLC, river water and sediment.